Merge Android 12HEADmaster

Bug: 202323961
Merged-In: I64e7be8bd815a3f3bf84277ffb9ea801a5dceb24
Change-Id: Ib2ecaa196b974cec584f6ae5c1e8b4092818d73a

45 files changed, 727 insertions, 318 deletions

diff --git a/src/com/android/documentsui/AbstractActionHandler.java b/src/com/android/documentsui/AbstractActionHandler.java
index 0c612eddd..a310acee2 100644
--- a/src/com/android/documentsui/AbstractActionHandler.java
+++ b/src/com/android/documentsui/AbstractActionHandler.java
@@ -76,6 +76,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.Executor;
+import java.util.concurrent.Semaphore;
 import java.util.function.Consumer;
 
 import javax.annotation.Nullable;
@@ -94,6 +95,7 @@ public abstract class AbstractActionHandler<T extends FragmentActivity & CommonA
 
     private static final String TAG = "AbstractActionHandler";
     private static final int REFRESH_SPINNER_TIMEOUT = 500;
+    private final Semaphore mLoaderSemaphore = new Semaphore(1);
 
     protected final T mActivity;
     protected final State mState;
@@ -745,7 +747,7 @@ public abstract class AbstractActionHandler<T extends FragmentActivity & CommonA
         public void onRootLoaded(@Nullable RootInfo root) {
             if (root == null) {
                 // There is no such root in the other profile. Maybe the provider is missing on
-                // the other profile. Create a dummy root and open it to show error message.
+                // the other profile. Create a placeholder root and open it to show error message.
                 root = RootInfo.copyRootInfo(mOriginalRoot);
                 root.userId = mSelectedUserId;
             }
@@ -767,7 +769,13 @@ public abstract class AbstractActionHandler<T extends FragmentActivity & CommonA
         // For RecentsLoader and GlobalSearchLoader, they do not require rootDoc so it is no-op.
         // For DirectoryLoader, the loader needs to handle the case when stack.peek() returns null.
 
-        mActivity.getSupportLoaderManager().restartLoader(LOADER_ID, null, mBindings);
+        // Only allow restartLoader when the previous loader is finished or reset. Allowing
+        // multiple consecutive calls to restartLoader() / onCreateLoader() will probably create
+        // multiple active loaders, because restartLoader() does not interrupt previous loaders'
+        // loading, therefore may block the UI thread and cause ANR.
+        if (mLoaderSemaphore.tryAcquire()) {
+            mActivity.getSupportLoaderManager().restartLoader(LOADER_ID, null, mBindings);
+        }
     }
 
     protected final boolean launchToDocument(Uri uri) {
@@ -942,10 +950,13 @@ public abstract class AbstractActionHandler<T extends FragmentActivity & CommonA
             assert(result != null);
 
             mInjector.getModel().update(result);
+            mLoaderSemaphore.release();
         }
 
         @Override
-        public void onLoaderReset(Loader<DirectoryResult> loader) {}
+        public void onLoaderReset(Loader<DirectoryResult> loader) {
+            mLoaderSemaphore.release();
+        }
     }
     /**
      * A class primarily for the support of isolating our tests
diff --git a/src/com/android/documentsui/ActionModeController.java b/src/com/android/documentsui/ActionModeController.java
index d8cf59000..89b8ff383 100644
--- a/src/com/android/documentsui/ActionModeController.java
+++ b/src/com/android/documentsui/ActionModeController.java
@@ -46,6 +46,7 @@ public class ActionModeController extends SelectionObserver<String>
 
     private final Activity mActivity;
     private final SelectionTracker<String> mSelectionMgr;
+    private final NavigationViewManager mNavigator;
     private final MenuManager mMenuManager;
     private final MessageBuilder mMessages;
 
@@ -58,11 +59,13 @@ public class ActionModeController extends SelectionObserver<String>
     public ActionModeController(
             Activity activity,
             SelectionTracker<String> selectionMgr,
+            NavigationViewManager navigator,
             MenuManager menuManager,
             MessageBuilder messages) {
 
         mActivity = activity;
         mSelectionMgr = selectionMgr;
+        mNavigator = navigator;
         mMenuManager = menuManager;
         mMessages = messages;
     }
@@ -132,6 +135,8 @@ public class ActionModeController extends SelectionObserver<String>
         // Re-enable TalkBack for the toolbars, as they are no longer covered by action mode.
         mScope.accessibilityImportanceSetter.setAccessibilityImportance(
                 View.IMPORTANT_FOR_ACCESSIBILITY_AUTO, R.id.toolbar, R.id.roots_toolbar);
+
+        mNavigator.setActionModeActivated(false);
     }
 
     @Override
@@ -141,6 +146,7 @@ public class ActionModeController extends SelectionObserver<String>
         mode.setTitle(mActivity.getResources().getQuantityString(R.plurals.selected_count, size));
 
         if (size > 0) {
+            mNavigator.setActionModeActivated(true);
 
             // Hide the toolbars if action mode is enabled, so TalkBack doesn't navigate to
             // these controls when using linear navigation.
diff --git a/src/com/android/documentsui/BaseActivity.java b/src/com/android/documentsui/BaseActivity.java
index 8c0d9693f..b4ab5bdf0 100644
--- a/src/com/android/documentsui/BaseActivity.java
+++ b/src/com/android/documentsui/BaseActivity.java
@@ -167,6 +167,11 @@ public abstract class BaseActivity
 
         mNavigator = new NavigationViewManager(this, mDrawer, mState, this, breadcrumb,
                 profileTabsContainer, DocumentsApplication.getUserIdManager(this));
+        AppBarLayout appBarLayout = findViewById(R.id.app_bar);
+        if (appBarLayout != null) {
+            appBarLayout.addOnOffsetChangedListener(mNavigator);
+        }
+
         SearchManagerListener searchListener = new SearchManagerListener() {
             /**
              * Called when search results changed. Refreshes the content of the directory. It
@@ -934,7 +939,7 @@ public abstract class BaseActivity
                 getMainLooper().getQueue().addIdleHandler(new IdleHandler() {
                     @Override
                     public boolean queueIdle() {
-                        // If startup benchmark is requested by a whitelisted testing package, then
+                        // If startup benchmark is requested by an allowedlist testing package, then
                         // close the activity once idle, and notify the testing activity.
                         if (getIntent().getBooleanExtra(EXTRA_BENCHMARK, false) &&
                                 BENCHMARK_TESTING_PACKAGE.equals(getCallingPackage())) {
diff --git a/src/com/android/documentsui/BreadcrumbHolder.java b/src/com/android/documentsui/BreadcrumbHolder.java
index 68c0e6a0e..4baaf9ca5 100644
--- a/src/com/android/documentsui/BreadcrumbHolder.java
+++ b/src/com/android/documentsui/BreadcrumbHolder.java
@@ -27,14 +27,12 @@ public final class BreadcrumbHolder extends RecyclerView.ViewHolder {
 
     protected TextView mTitle;
     protected ImageView mArrow;
-    protected int mDefaultTextColor;
     protected boolean mLast;
 
     public BreadcrumbHolder(View itemView) {
         super(itemView);
         mTitle = itemView.findViewById(R.id.breadcrumb_text);
         mArrow = itemView.findViewById(R.id.breadcrumb_arrow);
-        mDefaultTextColor = mTitle.getTextColors().getDefaultColor();
         mLast = false;
     }
 
diff --git a/src/com/android/documentsui/CreateDirectoryFragment.java b/src/com/android/documentsui/CreateDirectoryFragment.java
index 9ef58839b..4b066edb6 100644
--- a/src/com/android/documentsui/CreateDirectoryFragment.java
+++ b/src/com/android/documentsui/CreateDirectoryFragment.java
@@ -25,7 +25,6 @@ import android.content.ContentProviderClient;
 import android.content.ContentResolver;
 import android.content.Context;
 import android.content.DialogInterface;
-import android.content.DialogInterface.OnClickListener;
 import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Bundle;
@@ -37,6 +36,7 @@ import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.inputmethod.EditorInfo;
+import android.widget.Button;
 import android.widget.EditText;
 import android.widget.TextView;
 import android.widget.TextView.OnEditorActionListener;
@@ -59,6 +59,9 @@ import com.google.android.material.textfield.TextInputLayout;
  */
 public class CreateDirectoryFragment extends DialogFragment {
     private static final String TAG_CREATE_DIRECTORY = "create_directory";
+    private @Nullable DialogInterface mDialog;
+    private EditText mEditText;
+    private TextInputLayout mInputWrapper;
 
     public static void show(FragmentManager fm) {
         if (fm.isStateSaved()) {
@@ -78,30 +81,20 @@ public class CreateDirectoryFragment extends DialogFragment {
         final LayoutInflater dialogInflater = LayoutInflater.from(builder.getContext());
 
         final View view = dialogInflater.inflate(R.layout.dialog_file_name, null, false);
-        final EditText editText = (EditText) view.findViewById(android.R.id.text1);
+        mEditText = (EditText) view.findViewById(android.R.id.text1);
 
-        final TextInputLayout inputWrapper = view.findViewById(R.id.input_wrapper);
-        inputWrapper.setHint(getString(R.string.input_hint_new_folder));
+        mInputWrapper = view.findViewById(R.id.input_wrapper);
+        mInputWrapper.setHint(getString(R.string.input_hint_new_folder));
 
         builder.setTitle(R.string.menu_create_dir);
         builder.setView(view);
-
-        builder.setPositiveButton(
-                android.R.string.ok,
-                new OnClickListener() {
-                    @Override
-                    public void onClick(DialogInterface dialog, int which) {
-                        createDirectory(editText.getText().toString());
-                    }
-                });
-
+        builder.setPositiveButton(android.R.string.ok, null);
         builder.setNegativeButton(android.R.string.cancel, null);
         final AlertDialog dialog = builder.create();
-
+        dialog.setOnShowListener(this::onShowDialog);
         // Workaround for the problem - virtual keyboard doesn't show on the phone.
         Shared.ensureKeyboardPresent(context, dialog);
-
-        editText.setOnEditorActionListener(
+        mEditText.setOnEditorActionListener(
                 new OnEditorActionListener() {
                     @Override
                     public boolean onEditorAction(
@@ -109,24 +102,39 @@ public class CreateDirectoryFragment extends DialogFragment {
                         if ((actionId == EditorInfo.IME_ACTION_DONE) || (event != null
                                 && event.getKeyCode() == KeyEvent.KEYCODE_ENTER
                                 && event.hasNoModifiers())) {
-                            createDirectory(editText.getText().toString());
-                            dialog.dismiss();
+                            createDirectory(mEditText.getText().toString());
                             return true;
                         }
                         return false;
                     }
                 });
-        editText.requestFocus();
+        mEditText.requestFocus();
 
         return dialog;
     }
 
-    private void createDirectory(String name) {
-        final BaseActivity activity = (BaseActivity) getActivity();
-        final DocumentInfo cwd = activity.getCurrentDirectory();
+    private void onShowDialog(DialogInterface dialog) {
+        mDialog = dialog;
+        Button button = ((AlertDialog) dialog).getButton(AlertDialog.BUTTON_POSITIVE);
+        button.setOnClickListener(this::onClickDialog);
+    }
+
+    private void onClickDialog(View view) {
+        createDirectory(mEditText.getText().toString());
+    }
 
-        new CreateDirectoryTask(activity, cwd, name).executeOnExecutor(
-                ProviderExecutor.forAuthority(cwd.authority));
+    private void createDirectory(String name) {
+        if (name.isEmpty()) {
+            mInputWrapper.setError(getContext().getString(
+                    R.string.add_folder_name_error));
+        } else {
+            final BaseActivity activity = (BaseActivity) getActivity();
+            final DocumentInfo cwd = activity.getCurrentDirectory();
+
+            new CreateDirectoryTask(activity, cwd, name).executeOnExecutor(
+                    ProviderExecutor.forAuthority(cwd.authority));
+            mDialog.dismiss();
+        }
     }
 
     private class CreateDirectoryTask extends AsyncTask<Void, Void, DocumentInfo> {
diff --git a/src/com/android/documentsui/DirectoryLoader.java b/src/com/android/documentsui/DirectoryLoader.java
index 31963962a..816144758 100644
--- a/src/com/android/documentsui/DirectoryLoader.java
+++ b/src/com/android/documentsui/DirectoryLoader.java
@@ -56,8 +56,7 @@ import java.util.concurrent.Executor;
 public class DirectoryLoader extends AsyncTaskLoader<DirectoryResult> {
 
     private static final String TAG = "DirectoryLoader";
-
-    private static final String[] SEARCH_REJECT_MIMES = new String[] { Document.MIME_TYPE_DIR };
+    private static final String[] SEARCH_REJECT_MIMES = new String[]{Document.MIME_TYPE_DIR};
     private static final String[] PHOTO_PICKING_ACCEPT_MIMES = new String[]
             {Document.MIME_TYPE_DIR, MimeTypes.IMAGE_MIME};
 
@@ -178,17 +177,16 @@ public class DirectoryLoader extends AsyncTaskLoader<DirectoryResult> {
             }
             cursor.registerContentObserver(mObserver);
 
-            // Filter hidden files.
-            cursor = new FilteringCursorWrapper(cursor, mState.showHiddenFiles);
-
+            FilteringCursorWrapper filteringCursor = new FilteringCursorWrapper(cursor);
+            filteringCursor.filterHiddenFiles(mState.showHiddenFiles);
             if (mSearchMode && !mFeatures.isFoldersInSearchResultsEnabled()) {
                 // There is no findDocumentPath API. Enable filtering on folders in search mode.
-                cursor = new FilteringCursorWrapper(cursor, null, SEARCH_REJECT_MIMES);
+                filteringCursor.filterMimes(/* acceptMimes= */ null, SEARCH_REJECT_MIMES);
             }
-
             if (mPhotoPicking) {
-                cursor = new FilteringCursorWrapper(cursor, PHOTO_PICKING_ACCEPT_MIMES, null);
+                filteringCursor.filterMimes(PHOTO_PICKING_ACCEPT_MIMES, /* rejectMimes= */ null);
             }
+            cursor = filteringCursor;
 
             // TODO: When API tweaks have landed, use ContentResolver.EXTRA_HONORED_ARGS
             // instead of checking directly for ContentResolver.QUERY_ARG_SORT_COLUMNS (won't work)
@@ -198,7 +196,7 @@ public class DirectoryLoader extends AsyncTaskLoader<DirectoryResult> {
             } else {
                 cursor = mModel.sortCursor(cursor, mFileTypeLookup);
             }
-            result.cursor = cursor;
+            result.setCursor(cursor);
         } catch (Exception e) {
             Log.w(TAG, "Failed to query", e);
             result.exception = e;
@@ -307,8 +305,8 @@ public class DirectoryLoader extends AsyncTaskLoader<DirectoryResult> {
         // Ensure the loader is stopped
         onStopLoading();
 
-        if (mResult != null && mResult.cursor != null && mObserver != null) {
-            mResult.cursor.unregisterContentObserver(mObserver);
+        if (mResult != null && mResult.getCursor() != null && mObserver != null) {
+            mResult.getCursor().unregisterContentObserver(mObserver);
         }
 
         FileUtils.closeQuietly(mResult);
@@ -316,10 +314,10 @@ public class DirectoryLoader extends AsyncTaskLoader<DirectoryResult> {
     }
 
     private boolean checkIfCursorStale(DirectoryResult result) {
-        if (result == null || result.cursor == null || result.cursor.isClosed()) {
+        if (result == null || result.getCursor() == null || result.getCursor().isClosed()) {
             return true;
         }
-        Cursor cursor = result.cursor;
+        Cursor cursor = result.getCursor();
         try {
             cursor.moveToPosition(-1);
             for (int pos = 0; pos < cursor.getCount(); ++pos) {
diff --git a/src/com/android/documentsui/DirectoryResult.java b/src/com/android/documentsui/DirectoryResult.java
index f820db988..15ab0076d 100644
--- a/src/com/android/documentsui/DirectoryResult.java
+++ b/src/com/android/documentsui/DirectoryResult.java
@@ -16,29 +16,97 @@
 
 package com.android.documentsui;
 
+import static com.android.documentsui.base.DocumentInfo.getCursorString;
+
 import android.content.ContentProviderClient;
 import android.database.Cursor;
 import android.os.FileUtils;
+import android.provider.DocumentsContract;
+import android.util.Log;
 
 import com.android.documentsui.archives.ArchivesProvider;
 import com.android.documentsui.base.DocumentInfo;
 
+import java.util.HashSet;
+import java.util.Set;
+
 public class DirectoryResult implements AutoCloseable {
 
-    public Cursor cursor;
+    private static final String TAG = "DirectoryResult";
+
     public Exception exception;
     public DocumentInfo doc;
     ContentProviderClient client;
 
+    private Cursor mCursor;
+    private Set<String> mFileNames;
+    private String[] mModelIds;
+
     @Override
     public void close() {
-        FileUtils.closeQuietly(cursor);
+        FileUtils.closeQuietly(mCursor);
         if (client != null && doc.isInArchive()) {
             ArchivesProvider.releaseArchive(client, doc.derivedUri);
         }
         FileUtils.closeQuietly(client);
-        cursor = null;
         client = null;
         doc = null;
+
+        setCursor(null);
+    }
+
+    public Cursor getCursor() {
+        return mCursor;
+    }
+
+    public String[] getModelIds() {
+        return mModelIds;
+    }
+
+    public Set<String> getFileNames() {
+        return mFileNames;
+    }
+
+    /** Update the cursor and populate cursor-related fields. */
+    public void setCursor(Cursor cursor) {
+        mCursor = cursor;
+
+        if (mCursor == null) {
+            mFileNames = null;
+            mModelIds = null;
+        } else {
+            loadDataFromCursor();
+        }
+    }
+
+    /** Populate cursor-related field. Must not be called from UI thread. */
+    private void loadDataFromCursor() {
+        ThreadHelper.assertNotOnMainThread();
+        int cursorCount = mCursor.getCount();
+        String[] modelIds = new String[cursorCount];
+        Set<String> fileNames = new HashSet<>();
+        try {
+            mCursor.moveToPosition(-1);
+            for (int pos = 0; pos < cursorCount; ++pos) {
+                if (!mCursor.moveToNext()) {
+                    Log.e(TAG, "Fail to move cursor to next pos: " + pos);
+                    return;
+                }
+
+                // Generates a Model ID for a cursor entry that refers to a document. The Model
+                // ID is a unique string that can be used to identify the document referred to by
+                // the cursor. Prefix the ids with the authority to avoid collisions.
+                modelIds[pos] = ModelId.build(mCursor);
+                fileNames.add(
+                        getCursorString(mCursor, DocumentsContract.Document.COLUMN_DISPLAY_NAME));
+            }
+        } catch (Exception e) {
+            Log.e(TAG, "Exception when moving cursor. Stale cursor?", e);
+            return;
+        }
+
+        // Model related data is only non-null when no error iterating through cursor.
+        mModelIds = modelIds;
+        mFileNames = fileNames;
     }
 }
diff --git a/src/com/android/documentsui/DocsSelectionHelper.java b/src/com/android/documentsui/DocsSelectionHelper.java
index b7a720c8b..956527a2e 100644
--- a/src/com/android/documentsui/DocsSelectionHelper.java
+++ b/src/com/android/documentsui/DocsSelectionHelper.java
@@ -37,10 +37,10 @@ public final class DocsSelectionHelper extends SelectionTracker<String> {
 
     private final DelegateFactory mFactory;
 
-    // initialize to a dummy object incase we get some input
+    // initialize to a stub object incase we get some input
     // event drive calls before we're properly initialized.
     // See: b/69306667.
-    private SelectionTracker<String> mDelegate = new DummySelectionTracker<>();
+    private SelectionTracker<String> mDelegate = new StubSelectionTracker<>();
 
     @VisibleForTesting
     DocsSelectionHelper(DelegateFactory factory) {
diff --git a/src/com/android/documentsui/DrawerController.java b/src/com/android/documentsui/DrawerController.java
index cb536162d..56b3a879f 100644
--- a/src/com/android/documentsui/DrawerController.java
+++ b/src/com/android/documentsui/DrawerController.java
@@ -55,7 +55,7 @@ public abstract class DrawerController implements DrawerListener {
         DrawerLayout layout = (DrawerLayout) activity.findViewById(R.id.drawer_layout);
 
         if (layout == null) {
-            return new DummyDrawerController();
+            return new StubDrawerController();
         }
 
         View drawer = activity.findViewById(R.id.drawer_roots);
@@ -76,8 +76,8 @@ public abstract class DrawerController implements DrawerListener {
     /**
      * Returns a controller suitable for {@code Layout}.
      */
-    static DrawerController createDummy() {
-        return new DummyDrawerController();
+    static DrawerController createStub() {
+        return new StubDrawerController();
     }
 
     private static int calculateDrawerWidth(Activity activity) {
@@ -235,9 +235,9 @@ public abstract class DrawerController implements DrawerListener {
     }
 
     /*
-     * Dummy controller useful with clients that don't host a real drawer.
+     * Stub controller useful with clients that don't host a real drawer.
      */
-    private static final class DummyDrawerController extends DrawerController {
+    private static final class StubDrawerController extends DrawerController {
 
         @Override
         public void setOpen(boolean open) {}
diff --git a/src/com/android/documentsui/HorizontalBreadcrumb.java b/src/com/android/documentsui/HorizontalBreadcrumb.java
index 5cfc65e09..94f0e13f9 100644
--- a/src/com/android/documentsui/HorizontalBreadcrumb.java
+++ b/src/com/android/documentsui/HorizontalBreadcrumb.java
@@ -176,7 +176,6 @@ public final class HorizontalBreadcrumb extends RecyclerView implements Breadcru
         public void onBindViewHolder(BreadcrumbHolder holder, int position) {
             final int padding = (int) holder.itemView.getResources()
                     .getDimension(R.dimen.breadcrumb_item_padding);
-            final int enableColor = holder.itemView.getContext().getColor(R.color.primary);
             final boolean isFirst = position == 0;
             // Note that when isFirst is true, there might not be a DocumentInfo on the stack as it
             // could be an error state screen accessible from the root info.
@@ -184,7 +183,7 @@ public final class HorizontalBreadcrumb extends RecyclerView implements Breadcru
 
             holder.mTitle.setText(
                     isFirst ? mEnv.getCurrentRoot().title : mState.stack.get(position).displayName);
-            holder.mTitle.setTextColor(isLast ? enableColor : holder.mDefaultTextColor);
+            holder.mTitle.setEnabled(isLast);
             holder.mTitle.setPadding(isFirst ? padding * 3 : padding,
                     padding, isLast ? padding * 2 : padding, padding);
             holder.mArrow.setVisibility(isLast ? View.GONE : View.VISIBLE);
diff --git a/src/com/android/documentsui/Model.java b/src/com/android/documentsui/Model.java
index 49e3c9b26..fdcebae3c 100644
--- a/src/com/android/documentsui/Model.java
+++ b/src/com/android/documentsui/Model.java
@@ -16,7 +16,6 @@
 
 package com.android.documentsui;
 
-import static com.android.documentsui.base.DocumentInfo.getCursorString;
 import static com.android.documentsui.base.SharedMinimal.DEBUG;
 import static com.android.documentsui.base.SharedMinimal.VERBOSE;
 
@@ -25,7 +24,6 @@ import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
 import android.provider.DocumentsContract;
-import android.provider.DocumentsContract.Document;
 import android.util.Log;
 
 import androidx.annotation.IntDef;
@@ -125,11 +123,21 @@ public class Model {
             return;
         }
 
-        mCursor = result.cursor;
+        mCursor = result.getCursor();
         mCursorCount = mCursor.getCount();
         doc = result.doc;
 
-        updateModelData();
+        if (result.getModelIds() != null && result.getFileNames() != null) {
+            mIds = result.getModelIds();
+            mFileNames.clear();
+            mFileNames.addAll(result.getFileNames());
+
+            // Populate the positions.
+            mPositions.clear();
+            for (int i = 0; i < mCursorCount; ++i) {
+                mPositions.put(mIds[i], i);
+            }
+        }
 
         final Bundle extras = mCursor.getExtras();
         if (extras != null) {
@@ -146,33 +154,6 @@ public class Model {
         return mCursorCount;
     }
 
-    /**
-     * Scan over the incoming cursor data, generate Model IDs for each row, and sort the IDs
-     * according to the current sort order.
-     */
-    private void updateModelData() {
-        mIds = new String[mCursorCount];
-        mFileNames.clear();
-        mCursor.moveToPosition(-1);
-        for (int pos = 0; pos < mCursorCount; ++pos) {
-            if (!mCursor.moveToNext()) {
-                Log.e(TAG, "Fail to move cursor to next pos: " + pos);
-                return;
-            }
-            // Generates a Model ID for a cursor entry that refers to a document. The Model ID is a
-            // unique string that can be used to identify the document referred to by the cursor.
-            // Prefix the ids with the authority to avoid collisions.
-            mIds[pos] = ModelId.build(mCursor);
-            mFileNames.add(getCursorString(mCursor, Document.COLUMN_DISPLAY_NAME));
-        }
-
-        // Populate the positions.
-        mPositions.clear();
-        for (int i = 0; i < mCursorCount; ++i) {
-            mPositions.put(mIds[i], i);
-        }
-    }
-
     public boolean hasFileWithName(String name) {
         return mFileNames.contains(name);
     }
diff --git a/src/com/android/documentsui/MultiRootDocumentsLoader.java b/src/com/android/documentsui/MultiRootDocumentsLoader.java
index e7d09bfd3..7668b0693 100644
--- a/src/com/android/documentsui/MultiRootDocumentsLoader.java
+++ b/src/com/android/documentsui/MultiRootDocumentsLoader.java
@@ -104,8 +104,6 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
      * @param state current state
      * @param executors the executors of authorities
      * @param fileTypeMap the map of mime types and file types.
-     * @param lock the selection lock
-     * @param contentChangedCallback callback when content changed
      */
     public MultiRootDocumentsLoader(Context context, ProvidersAccess providers, State state,
             Lookup<String, Executor> executors, Lookup<String, String> fileTypeMap) {
@@ -126,8 +124,13 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
 
     @Override
     public DirectoryResult loadInBackground() {
-        synchronized (mTasks) {
-            return loadInBackgroundLocked();
+        try {
+            synchronized (mTasks) {
+                return loadInBackgroundLocked();
+            }
+        } catch (InterruptedException e) {
+            Log.w(TAG, "loadInBackground is interrupted: ", e);
+            return null;
         }
     }
 
@@ -135,7 +138,7 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
         mObserver = observer;
     }
 
-    private DirectoryResult loadInBackgroundLocked() {
+    private DirectoryResult loadInBackgroundLocked() throws InterruptedException {
         if (mFirstPassLatch == null) {
             // First time through we kick off all the recent tasks, and wait
             // around to see if everyone finishes quickly.
@@ -146,6 +149,11 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
                         getQueryTask(rootEntry.getKey(), rootEntry.getValue()));
             }
 
+            if (isLoadInBackgroundCanceled()) {
+                // Loader is cancelled (e.g. about to be reset), preempt loading.
+                throw new InterruptedException("Loading is cancelled!");
+            }
+
             mFirstPassLatch = new CountDownLatch(mTasks.size());
             for (QueryTask task : mTasks.values()) {
                 mExecutors.lookup(task.authority).execute(task);
@@ -166,6 +174,11 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
         int totalQuerySize = 0;
         List<Cursor> cursors = new ArrayList<>(mTasks.size());
         for (QueryTask task : mTasks.values()) {
+            if (isLoadInBackgroundCanceled()) {
+                // Loader is cancelled (e.g. about to be reset), preempt loading.
+                throw new InterruptedException("Loading is cancelled!");
+            }
+
             if (task.isDone()) {
                 try {
                     final Cursor[] taskCursors = task.get();
@@ -181,17 +194,18 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
                             continue;
                         }
 
-                        // Filter hidden files.
-                        cursor = new FilteringCursorWrapper(cursor, mState.showHiddenFiles);
-
-                        final FilteringCursorWrapper filtered = new FilteringCursorWrapper(
-                                cursor, mState.acceptMimes, getRejectMimes(), rejectBefore) {
+                        final FilteringCursorWrapper filteredCursor =
+                                new FilteringCursorWrapper(cursor) {
                             @Override
                             public void close() {
                                 // Ignored, since we manage cursor lifecycle internally
                             }
                         };
-                        cursors.add(filtered);
+                        filteredCursor.filterHiddenFiles(mState.showHiddenFiles);
+                        filteredCursor.filterMimes(mState.acceptMimes, getRejectMimes());
+                        filteredCursor.filterLastModified(rejectBefore);
+
+                        cursors.add(filteredCursor);
                     }
 
                 } catch (InterruptedException e) {
@@ -238,7 +252,7 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
         extras.putBoolean(DocumentsContract.EXTRA_LOADING, !allDone);
         sorted.setExtras(extras);
 
-        result.cursor = sorted;
+        result.setCursor(sorted);
 
         return result;
     }
@@ -292,7 +306,7 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
         DirectoryResult oldResult = mResult;
         mResult = result;
 
-        if (isStarted()) {
+        if (isStarted() && !isAbandoned() && !isLoadInBackgroundCanceled()) {
             super.deliverResult(result);
         }
 
@@ -326,9 +340,6 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
     protected void onReset() {
         super.onReset();
 
-        // Ensure the loader is stopped
-        onStopLoading();
-
         synchronized (mTasks) {
             for (QueryTask task : mTasks.values()) {
                 mExecutors.lookup(task.authority).execute(() -> FileUtils.closeQuietly(task));
@@ -459,10 +470,10 @@ public abstract class MultiRootDocumentsLoader extends AsyncTaskLoader<Directory
     }
 
     private boolean checkIfCursorStale(DirectoryResult result) {
-        if (result == null || result.cursor == null || result.cursor.isClosed()) {
+        if (result == null || result.getCursor() == null || result.getCursor().isClosed()) {
             return true;
         }
-        Cursor cursor = result.cursor;
+        Cursor cursor = result.getCursor();
         try {
             cursor.moveToPosition(-1);
             for (int pos = 0; pos < cursor.getCount(); ++pos) {
diff --git a/src/com/android/documentsui/NavigationViewManager.java b/src/com/android/documentsui/NavigationViewManager.java
index 204971dce..83979ab6e 100644
--- a/src/com/android/documentsui/NavigationViewManager.java
+++ b/src/com/android/documentsui/NavigationViewManager.java
@@ -19,35 +19,44 @@ package com.android.documentsui;
 import static com.android.documentsui.base.SharedMinimal.VERBOSE;
 
 import android.content.res.Resources;
+import android.content.res.TypedArray;
 import android.graphics.Outline;
+import android.graphics.drawable.ColorDrawable;
 import android.graphics.drawable.Drawable;
 import android.util.Log;
 import android.view.View;
 import android.view.ViewOutlineProvider;
+import android.view.Window;
+import android.view.WindowManager;
+import android.widget.FrameLayout;
 
+import androidx.annotation.ColorRes;
 import androidx.annotation.Nullable;
 import androidx.appcompat.widget.Toolbar;
+import androidx.core.content.ContextCompat;
 
 import com.android.documentsui.base.RootInfo;
 import com.android.documentsui.base.State;
 import com.android.documentsui.base.UserId;
 import com.android.documentsui.dirlist.AnimationView;
+import com.android.documentsui.util.VersionUtils;
 
 import com.google.android.material.appbar.AppBarLayout;
 import com.google.android.material.appbar.CollapsingToolbarLayout;
-import com.google.android.material.tabs.TabLayout;
 
 import java.util.function.IntConsumer;
 
 /**
  * A facade over the portions of the app and drawer toolbars.
  */
-public class NavigationViewManager {
+public class NavigationViewManager implements AppBarLayout.OnOffsetChangedListener {
 
     private static final String TAG = "NavigationViewManager";
 
     private final DrawerController mDrawer;
     private final Toolbar mToolbar;
+    private final BaseActivity mActivity;
+    private final View mHeader;
     private final State mState;
     private final NavigationViewManager.Environment mEnv;
     private final Breadcrumb mBreadcrumb;
@@ -55,9 +64,13 @@ public class NavigationViewManager {
     private final View mSearchBarView;
     private final CollapsingToolbarLayout mCollapsingBarLayout;
     private final Drawable mDefaultActionBarBackground;
+    private final ViewOutlineProvider mDefaultOutlineProvider;
     private final ViewOutlineProvider mSearchBarOutlineProvider;
     private final boolean mShowSearchBar;
 
+    private boolean mIsActionModeActivated = false;
+    private @ColorRes int mDefaultStatusBarColorResId;
+
     public NavigationViewManager(
             BaseActivity activity,
             DrawerController drawer,
@@ -67,7 +80,9 @@ public class NavigationViewManager {
             View tabLayoutContainer,
             UserIdManager userIdManager) {
 
+        mActivity = activity;
         mToolbar = activity.findViewById(R.id.toolbar);
+        mHeader = activity.findViewById(R.id.directory_header);
         mDrawer = drawer;
         mState = state;
         mEnv = env;
@@ -85,8 +100,18 @@ public class NavigationViewManager {
         mSearchBarView = activity.findViewById(R.id.searchbar_title);
         mCollapsingBarLayout = activity.findViewById(R.id.collapsing_toolbar);
         mDefaultActionBarBackground = mToolbar.getBackground();
+        mDefaultOutlineProvider = mToolbar.getOutlineProvider();
         mShowSearchBar = activity.getResources().getBoolean(R.bool.show_search_bar);
 
+        final int[] styledAttrs = {android.R.attr.statusBarColor};
+        TypedArray a = mActivity.obtainStyledAttributes(styledAttrs);
+        mDefaultStatusBarColorResId = a.getResourceId(0, -1);
+        if (mDefaultStatusBarColorResId == -1) {
+            Log.w(TAG, "Retrieve statusBarColorResId from theme failed, assigned default");
+            mDefaultStatusBarColorResId = R.color.app_background_color;
+        }
+        a.recycle();
+
         final Resources resources = mToolbar.getResources();
         final int radius = resources.getDimensionPixelSize(R.dimen.search_bar_radius);
         final int marginStart =
@@ -102,6 +127,36 @@ public class NavigationViewManager {
         };
     }
 
+    @Override
+    public void onOffsetChanged(AppBarLayout appBarLayout, int offset) {
+        if (!VersionUtils.isAtLeastS()) {
+            return;
+        }
+
+        // For S+ Only. Change toolbar color dynamically based on scroll offset.
+        // Usually this can be done in xml using app:contentScrim and app:statusBarScrim, however
+        // in our case since we also put directory_header.xml inside the CollapsingToolbarLayout,
+        // the scrim will also cover the directory header. Long term need to think about how to
+        // move directory_header out of the AppBarLayout.
+
+        Window window = mActivity.getWindow();
+        View actionBar = window.getDecorView().findViewById(R.id.action_mode_bar);
+        int dynamicHeaderColor = ContextCompat.getColor(mActivity,
+                offset == 0 ? mDefaultStatusBarColorResId : R.color.color_surface_header);
+        if (actionBar != null) {
+            // Action bar needs to be updated separately for selection mode.
+            actionBar.setBackgroundColor(dynamicHeaderColor);
+        }
+
+        window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
+        window.setStatusBarColor(dynamicHeaderColor);
+        if (shouldShowSearchBar()) {
+            // Do not change search bar background.
+        } else {
+            mToolbar.setBackground(new ColorDrawable(dynamicHeaderColor));
+        }
+    }
+
     public void setSearchBarClickListener(View.OnClickListener listener) {
         mSearchBarView.setOnClickListener(listener);
     }
@@ -138,6 +193,11 @@ public class NavigationViewManager {
         return mProfileTabs.getSelectedUser();
     }
 
+    public void setActionModeActivated(boolean actionModeActivated) {
+        mIsActionModeActivated = actionModeActivated;
+        update();
+    }
+
     public void update() {
         updateScrollFlag();
         updateToolbar();
@@ -177,30 +237,57 @@ public class NavigationViewManager {
 
         AppBarLayout.LayoutParams lp =
                 (AppBarLayout.LayoutParams) mCollapsingBarLayout.getLayoutParams();
-        if (shouldShowSearchBar()) {
-            lp.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL
-                            | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS
-                            | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS_COLLAPSED);
-        } else {
-            lp.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL
-                            | AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED);
-        }
+        lp.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL
+                | AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED);
         mCollapsingBarLayout.setLayoutParams(lp);
     }
 
     private void updateToolbar() {
-        if (shouldShowSearchBar()) {
+        if (mCollapsingBarLayout == null) {
+            // Tablet mode does not use CollapsingBarLayout
+            // (res/layout-sw720dp/directory_app_bar.xml or res/layout/fixed_layout.xml)
+            if (shouldShowSearchBar()) {
+                mToolbar.setBackgroundResource(R.drawable.search_bar_background);
+                mToolbar.setOutlineProvider(mSearchBarOutlineProvider);
+            } else {
+                mToolbar.setBackground(mDefaultActionBarBackground);
+                mToolbar.setOutlineProvider(null);
+            }
+            return;
+        }
+
+        CollapsingToolbarLayout.LayoutParams toolbarLayoutParams =
+                (CollapsingToolbarLayout.LayoutParams) mToolbar.getLayoutParams();
+
+        int headerTopOffset = 0;
+        if (shouldShowSearchBar() && !mIsActionModeActivated) {
             mToolbar.setBackgroundResource(R.drawable.search_bar_background);
             mToolbar.setOutlineProvider(mSearchBarOutlineProvider);
+            int searchBarMargin = mToolbar.getResources().getDimensionPixelSize(
+                    R.dimen.search_bar_margin);
+            toolbarLayoutParams.setMargins(searchBarMargin, searchBarMargin, searchBarMargin,
+                    searchBarMargin);
+            mToolbar.setLayoutParams(toolbarLayoutParams);
+            mToolbar.setElevation(
+                    mToolbar.getResources().getDimensionPixelSize(R.dimen.search_bar_elevation));
+            headerTopOffset = toolbarLayoutParams.height + searchBarMargin * 2;
         } else {
             mToolbar.setBackground(mDefaultActionBarBackground);
-            mToolbar.setOutlineProvider(null);
+            mToolbar.setOutlineProvider(mDefaultOutlineProvider);
+            int actionBarMargin = mToolbar.getResources().getDimensionPixelSize(
+                    R.dimen.action_bar_margin);
+            toolbarLayoutParams.setMargins(0, 0, 0, /* bottom= */ actionBarMargin);
+            mToolbar.setLayoutParams(toolbarLayoutParams);
+            mToolbar.setElevation(
+                    mToolbar.getResources().getDimensionPixelSize(R.dimen.action_bar_elevation));
+            headerTopOffset = toolbarLayoutParams.height + actionBarMargin;
         }
 
-        if (mCollapsingBarLayout != null) {
-            View overlayBackground =
-                    mCollapsingBarLayout.findViewById(R.id.toolbar_background_layout);
-            overlayBackground.setVisibility(shouldShowSearchBar() ? View.GONE : View.VISIBLE);
+        if (!mIsActionModeActivated) {
+            FrameLayout.LayoutParams headerLayoutParams =
+                    (FrameLayout.LayoutParams) mHeader.getLayoutParams();
+            headerLayoutParams.setMargins(0, /* top= */ headerTopOffset, 0, 0);
+            mHeader.setLayoutParams(headerLayoutParams);
         }
     }
 
@@ -209,7 +296,8 @@ public class NavigationViewManager {
     }
 
     // Hamburger if drawer is present, else sad nullness.
-    private @Nullable Drawable getActionBarIcon() {
+    private @Nullable
+    Drawable getActionBarIcon() {
         if (mDrawer.isPresent()) {
             return mToolbar.getContext().getDrawable(R.drawable.ic_hamburger);
         } else {
@@ -223,16 +311,23 @@ public class NavigationViewManager {
 
     interface Breadcrumb {
         void setup(Environment env, State state, IntConsumer listener);
+
         void show(boolean visibility);
+
         void postUpdate();
     }
 
     interface Environment {
-        @Deprecated  // Use CommonAddones#getCurrentRoot
+        @Deprecated
+            // Use CommonAddones#getCurrentRoot
         RootInfo getCurrentRoot();
+
         String getDrawerTitle();
-        @Deprecated  // Use CommonAddones#refreshCurrentRootAndDirectory
+
+        @Deprecated
+            // Use CommonAddones#refreshCurrentRootAndDirectory
         void refreshCurrentRootAndDirectory(int animation);
+
         boolean isSearchExpanded();
     }
 }
diff --git a/src/com/android/documentsui/PreBootReceiver.java b/src/com/android/documentsui/PreBootReceiver.java
index c47631654..f5ad9395a 100644
--- a/src/com/android/documentsui/PreBootReceiver.java
+++ b/src/com/android/documentsui/PreBootReceiver.java
@@ -30,6 +30,7 @@ import android.content.res.Resources;
 import android.util.Log;
 
 import com.android.documentsui.theme.ThemeOverlayManager;
+import com.android.documentsui.util.VersionUtils;
 
 /**
  * A receiver listening action.PRE_BOOT_COMPLETED event for setting component enable or disable.
@@ -91,11 +92,15 @@ public class PreBootReceiver extends BroadcastReceiver {
         int resId = overlayRes.getIdentifier(config, "bool", overlayPkg);
         if (resId != 0) {
             final ComponentName component = new ComponentName(packageName, className);
-            final boolean value = overlayRes.getBoolean(resId);
+            boolean enabled = overlayRes.getBoolean(resId);
+            if (VersionUtils.isAtLeastS() && CONFIG_IS_LAUNCHER_ENABLED.equals(config)) {
+                enabled = false; // Do not allow LauncherActivity to be enabled for S+.
+            }
             if (DEBUG) {
-                Log.i(TAG, "Overlay package:" + overlayPkg + ", customize " + config + ":" + value);
+                Log.i(TAG,
+                        "Overlay package:" + overlayPkg + ", customize " + config + ":" + enabled);
             }
-            pm.setComponentEnabledSetting(component, value
+            pm.setComponentEnabledSetting(component, enabled
                             ? PackageManager.COMPONENT_ENABLED_STATE_ENABLED
                             : PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
                     PackageManager.DONT_KILL_APP);
diff --git a/src/com/android/documentsui/RootsMonitor.java b/src/com/android/documentsui/RootsMonitor.java
index d4354b4cb..e87e53a64 100644
--- a/src/com/android/documentsui/RootsMonitor.java
+++ b/src/com/android/documentsui/RootsMonitor.java
@@ -22,7 +22,6 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.net.Uri;
-
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 
 import com.android.documentsui.AbstractActionHandler.CommonAddons;
@@ -137,7 +136,7 @@ final class RootsMonitor<T extends Activity & CommonAddons> {
             // activity.
             final Uri uri = mOwner.getIntent().getData();
             if (uri != null && uri.equals(mCurrentRoot.getUri())) {
-                mOwner.finishAndRemoveTask();
+                mOwner.finish();
                 return;
             }
 
diff --git a/src/com/android/documentsui/DummyProfileTabsAddons.java b/src/com/android/documentsui/StubProfileTabsAddons.java
index 697025e23..cac175945 100644
--- a/src/com/android/documentsui/DummyProfileTabsAddons.java
+++ b/src/com/android/documentsui/StubProfileTabsAddons.java
@@ -17,9 +17,9 @@
 package com.android.documentsui;
 
 /**
- * A dummy {@ProfileTabsAddons} implementation.
+ * A stub {@ProfileTabsAddons} implementation.
  */
-public class DummyProfileTabsAddons implements ProfileTabsAddons {
+public class StubProfileTabsAddons implements ProfileTabsAddons {
 
     @Override
     public void setEnabled(boolean enabled) {
diff --git a/src/com/android/documentsui/DummySelectionTracker.java b/src/com/android/documentsui/StubSelectionTracker.java
index 49b9ad918..1a392144f 100644
--- a/src/com/android/documentsui/DummySelectionTracker.java
+++ b/src/com/android/documentsui/StubSelectionTracker.java
@@ -26,10 +26,11 @@ import androidx.recyclerview.widget.RecyclerView.AdapterDataObserver;
 import java.util.Set;
 
 /**
- * A dummy SelectionTracker used by DocsSelectionHelper before a real SelectionTracker has been
+ * A stub SelectionTracker used by DocsSelectionHelper before a real SelectionTracker has been
  * initialized by DirectoryFragment.
+ * @param <K> Selection key type which extends {@link SelectionTracker}.
  */
-public class DummySelectionTracker<K> extends SelectionTracker<K> {
+public class StubSelectionTracker<K> extends SelectionTracker<K> {
 
     @Override
     public void addObserver(SelectionObserver observer) {
diff --git a/src/com/android/documentsui/ThreadHelper.java b/src/com/android/documentsui/ThreadHelper.java
new file mode 100644
index 000000000..bb123b69b
--- /dev/null
+++ b/src/com/android/documentsui/ThreadHelper.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.documentsui;
+
+import android.os.Looper;
+
+/** Class for handler/thread utils. */
+public final class ThreadHelper {
+    private ThreadHelper() {
+    }
+
+    static final String MUST_NOT_ON_MAIN_THREAD_MSG =
+            "This method should not be called on main thread.";
+    static final String MUST_ON_MAIN_THREAD_MSG =
+            "This method should only be called on main thread.";
+
+    /** Verifies that current thread is not the UI thread. */
+    public static void assertNotOnMainThread() {
+        if (Looper.getMainLooper().getThread() == Thread.currentThread()) {
+            fatalAssert(MUST_NOT_ON_MAIN_THREAD_MSG);
+        }
+    }
+
+    /** Verifies that current thread is the UI thread. */
+    public static void assertOnMainThread() {
+        if (Looper.getMainLooper().getThread() != Thread.currentThread()) {
+            fatalAssert(MUST_ON_MAIN_THREAD_MSG);
+        }
+    }
+
+    /**
+     * Exceptions thrown in background threads are silently swallowed on Android. Use the
+     * uncaught exception handler of the UI thread to force the app to crash.
+     */
+    public static void fatalAssert(final String message) {
+        crashMainThread(new AssertionError(message));
+    }
+
+    private static void crashMainThread(Throwable t) {
+        Thread.UncaughtExceptionHandler uiThreadExceptionHandler =
+                Looper.getMainLooper().getThread().getUncaughtExceptionHandler();
+        uiThreadExceptionHandler.uncaughtException(Thread.currentThread(), t);
+    }
+}
diff --git a/src/com/android/documentsui/archives/ArchiveEntryInputStream.java b/src/com/android/documentsui/archives/ArchiveEntryInputStream.java
index 0b1c0c2e6..2c34e5a71 100644
--- a/src/com/android/documentsui/archives/ArchiveEntryInputStream.java
+++ b/src/com/android/documentsui/archives/ArchiveEntryInputStream.java
@@ -20,16 +20,16 @@ import android.text.TextUtils;
 
 import androidx.annotation.NonNull;
 
-import java.io.Closeable;
-import java.io.IOException;
-import java.io.InputStream;
-
 import org.apache.commons.compress.archivers.ArchiveEntry;
 import org.apache.commons.compress.archivers.ArchiveInputStream;
 import org.apache.commons.compress.archivers.sevenz.SevenZFile;
 import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
 import org.apache.commons.compress.archivers.zip.ZipFile;
 
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+
 /**
  * To simulate the input stream by using ZipFile, SevenZFile, or ArchiveInputStream.
  */
@@ -124,7 +124,7 @@ abstract class ArchiveEntryInputStream extends InputStream {
             throw new IllegalArgumentException("ArchiveEntry is empty");
         }
 
-        if (archiveEntry.isDirectory() || archiveEntry.getSize() <= 0
+        if (archiveEntry.isDirectory() || archiveEntry.getSize() < 0
                 || TextUtils.isEmpty(archiveEntry.getName())) {
             throw new IllegalArgumentException("ArchiveEntry is an invalid file entry");
         }
diff --git a/src/com/android/documentsui/base/FilteringCursorWrapper.java b/src/com/android/documentsui/base/FilteringCursorWrapper.java
index 9e557b4aa..577e47c33 100644
--- a/src/com/android/documentsui/base/FilteringCursorWrapper.java
+++ b/src/com/android/documentsui/base/FilteringCursorWrapper.java
@@ -29,67 +29,62 @@ import android.provider.DocumentsContract.Document;
 import android.util.Log;
 
 /**
- * Cursor wrapper that filters MIME types not matching given list.
+ * Cursor wrapper that filters cursor results by given conditions.
  */
 public class FilteringCursorWrapper extends AbstractCursor {
     private final Cursor mCursor;
 
-    private final int[] mPosition;
+    private int[] mPositions;
     private int mCount;
 
-    public FilteringCursorWrapper(Cursor cursor, String[] acceptMimes) {
-        this(cursor, acceptMimes, null, Long.MIN_VALUE);
-    }
-
-    public FilteringCursorWrapper(Cursor cursor, String[] acceptMimes, String[] rejectMimes) {
-        this(cursor, acceptMimes, rejectMimes, Long.MIN_VALUE);
-    }
-
-    public FilteringCursorWrapper(
-            Cursor cursor, String[] acceptMimes, String[] rejectMimes, long rejectBefore) {
+    public FilteringCursorWrapper(Cursor cursor) {
         mCursor = cursor;
+        mCount = cursor.getCount();
+        mPositions = new int[mCount];
+        for (int i = 0; i < mCount; i++) {
+            mPositions[i] = i;
+        }
+    }
 
-        final int count = cursor.getCount();
-        mPosition = new int[count];
-
-        cursor.moveToPosition(-1);
-        while (cursor.moveToNext() && mCount < count) {
+    /**
+     * Filters cursor according to mimes. If both lists are empty, all mimes will be rejected.
+     *
+     * @param acceptMimes allowed list of mimes
+     * @param rejectMimes blocked list of mimes
+     */
+    public void filterMimes(String[] acceptMimes, String[] rejectMimes) {
+        filterByCondition((cursor) -> {
             final String mimeType = getCursorString(cursor, Document.COLUMN_MIME_TYPE);
-            final long lastModified = getCursorLong(cursor, Document.COLUMN_LAST_MODIFIED);
             if (rejectMimes != null && MimeTypes.mimeMatches(rejectMimes, mimeType)) {
-                continue;
+                return false;
             }
-            if (lastModified < rejectBefore) {
-                continue;
-            }
-            if (MimeTypes.mimeMatches(acceptMimes, mimeType)) {
-                mPosition[mCount++] = cursor.getPosition();
-            }
-        }
-
-        if (DEBUG && mCount != cursor.getCount()) {
-            Log.d(TAG, "Before filtering " + cursor.getCount() + ", after " + mCount);
-        }
+            return MimeTypes.mimeMatches(acceptMimes, mimeType);
+        });
     }
 
-    public FilteringCursorWrapper(Cursor cursor, boolean showHiddenFiles) {
-        mCursor = cursor;
-
-        final int count = cursor.getCount();
-        mPosition = new int[count];
+    /** Filters cursor according to last modified time, and reject earlier than given timestamp. */
+    public void filterLastModified(long rejectBeforeTimestamp) {
+        filterByCondition((cursor) -> {
+            final long lastModified = getCursorLong(cursor, Document.COLUMN_LAST_MODIFIED);
+            return lastModified >= rejectBeforeTimestamp;
+        });
+    }
 
-        cursor.moveToPosition(-1);
-        while (cursor.moveToNext() && mCount < count) {
-            final String name = getCursorString(cursor, Document.COLUMN_DISPLAY_NAME);
-            if (!showHiddenFiles && name != null && name.startsWith(".")) {
-                continue;
-            }
-            mPosition[mCount++] = cursor.getPosition();
+    /** Filter hidden files based on preference. */
+    public void filterHiddenFiles(boolean showHiddenFiles) {
+        if (showHiddenFiles) {
+            return;
         }
 
-        if (DEBUG && mCount != cursor.getCount()) {
-            Log.d(TAG, "Before filtering " + cursor.getCount() + ", after " + mCount);
-        }
+        filterByCondition((cursor) -> {
+            // Judge by name and documentId separately because for some providers
+            // e.g. DownloadProvider, documentId may not contain file name.
+            final String name = getCursorString(cursor, Document.COLUMN_DISPLAY_NAME);
+            final String documentId = getCursorString(cursor, Document.COLUMN_DOCUMENT_ID);
+            boolean documentIdHidden = documentId != null && documentId.contains("/.");
+            boolean fileNameHidden = name != null && name.startsWith(".");
+            return !(documentIdHidden || fileNameHidden);
+        });
     }
 
     @Override
@@ -105,7 +100,7 @@ public class FilteringCursorWrapper extends AbstractCursor {
 
     @Override
     public boolean onMove(int oldPosition, int newPosition) {
-        return mCursor.moveToPosition(mPosition[newPosition]);
+        return mCursor.moveToPosition(mPositions[newPosition]);
     }
 
     @Override
@@ -167,4 +162,27 @@ public class FilteringCursorWrapper extends AbstractCursor {
     public void unregisterContentObserver(ContentObserver observer) {
         mCursor.unregisterContentObserver(observer);
     }
+
+    private interface FilteringCondition {
+        boolean accept(Cursor cursor);
+    }
+
+    private void filterByCondition(FilteringCondition condition) {
+        final int oldCount = this.getCount();
+        int[] newPositions = new int[oldCount];
+        int newCount = 0;
+
+        this.moveToPosition(-1);
+        while (this.moveToNext() && newCount < oldCount) {
+            if (condition.accept(mCursor)) {
+                newPositions[newCount++] = mPositions[this.getPosition()];
+            }
+        }
+
+        if (DEBUG && newCount != this.getCount()) {
+            Log.d(TAG, "Before filtering " + oldCount + ", after " + newCount);
+        }
+        mCount = newCount;
+        mPositions = newPositions;
+    }
 }
diff --git a/src/com/android/documentsui/base/Shared.java b/src/com/android/documentsui/base/Shared.java
index f0f650b7b..5ac9de4d7 100644
--- a/src/com/android/documentsui/base/Shared.java
+++ b/src/com/android/documentsui/base/Shared.java
@@ -171,6 +171,10 @@ public final class Shared {
      * Whether the calling app should be restricted in Storage Access Framework or not.
      */
     public static boolean shouldRestrictStorageAccessFramework(Activity activity) {
+        if (VersionUtils.isAtLeastS()) {
+            return true;
+        }
+
         if (!VersionUtils.isAtLeastR()) {
             return false;
         }
@@ -314,7 +318,8 @@ public final class Shared {
     public static void ensureKeyboardPresent(Context context, AlertDialog dialog) {
         if (!isHardwareKeyboardAvailable(context)) {
             dialog.getWindow().setSoftInputMode(
-                    WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);
+                    WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE
+                            | WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN);
         }
     }
 
diff --git a/src/com/android/documentsui/base/DummyLookup.java b/src/com/android/documentsui/base/StubLookup.java
index 11a637580..2a2dc9bf1 100644
--- a/src/com/android/documentsui/base/DummyLookup.java
+++ b/src/com/android/documentsui/base/StubLookup.java
@@ -17,8 +17,10 @@ package com.android.documentsui.base;
 
 /**
  * Lookup that always returns null.
+ * @param <K> input type (the "key") which implements {@link Lookup}.
+ * @param <V> output type (the "value") which implements {@link Lookup}.
  */
-public final class DummyLookup<K, V> implements Lookup<K, V> {
+public final class StubLookup<K, V> implements Lookup<K, V> {
     @Override
     public V lookup(K key) {
         return null;
diff --git a/src/com/android/documentsui/dirlist/DirectoryFragment.java b/src/com/android/documentsui/dirlist/DirectoryFragment.java
index 8fa02ca46..25efb8c50 100644
--- a/src/com/android/documentsui/dirlist/DirectoryFragment.java
+++ b/src/com/android/documentsui/dirlist/DirectoryFragment.java
@@ -180,6 +180,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
     private SelectionMetadata mSelectionMetadata;
     private KeyInputHandler mKeyListener;
     private @Nullable DragHoverListener mDragHoverListener;
+    private View mRootView;
     private IconHelper mIconHelper;
     private SwipeRefreshLayout mRefreshLayout;
     private RecyclerView mRecView;
@@ -348,12 +349,12 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
         mHandler = new Handler(Looper.getMainLooper());
         mActivity = (BaseActivity) getActivity();
-        final View view = inflater.inflate(R.layout.fragment_directory, container, false);
+        mRootView = inflater.inflate(R.layout.fragment_directory, container, false);
 
-        mProgressBar = view.findViewById(R.id.progressbar);
+        mProgressBar = mRootView.findViewById(R.id.progressbar);
         assert mProgressBar != null;
 
-        mRecView = (RecyclerView) view.findViewById(R.id.dir_list);
+        mRecView = (RecyclerView) mRootView.findViewById(R.id.dir_list);
         mRecView.setRecyclerListener(
                 new RecyclerListener() {
                     @Override
@@ -362,12 +363,12 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                     }
                 });
 
-        mRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.refresh_layout);
+        mRefreshLayout = (SwipeRefreshLayout) mRootView.findViewById(R.id.refresh_layout);
         mRefreshLayout.setOnRefreshListener(this);
         mRecView.setItemAnimator(new DirectoryItemAnimator());
 
         mInjector = mActivity.getInjector();
-        // Initially, this selection tracker (delegator) uses a dummy implementation, so it must be
+        // Initially, this selection tracker (delegator) uses a stub implementation, so it must be
         // updated (reset) when necessary things are ready.
         mSelectionMgr = mInjector.selectionMgr;
         mModel = mInjector.getModel();
@@ -398,7 +399,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
         setPreDrawListenerEnabled(true);
 
-        return view;
+        return mRootView;
     }
 
     @Override
@@ -492,7 +493,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                         this::getModelId,
                         mRecView::findChildViewUnder,
                         DocumentsApplication.getDragAndDropManager(mActivity))
-                : DragStartListener.DUMMY;
+                : DragStartListener.STUB;
 
         {
             // Limiting the scope of the localTracker so nobody uses it.
@@ -585,6 +586,9 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
         // Add listener to update contents on sort model change
         mState.sortModel.addListener(mSortListener);
+        // After SD card is formatted, we go out of the view and come back. Similarly when users
+        // go out of the app to delete some files, we want to refresh the directory.
+        onRefresh();
     }
 
     @Override
@@ -684,6 +688,9 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
 
     public void onViewModeChanged() {
         // Mode change is just visual change; no need to kick loader.
+        mRootView.announceForAccessibility(getString(
+                mState.derivedMode == State.MODE_GRID ? R.string.grid_mode_showing
+                        : R.string.list_mode_showing));
         onDisplayStateChanged();
     }
 
diff --git a/src/com/android/documentsui/dirlist/DocumentsAdapter.java b/src/com/android/documentsui/dirlist/DocumentsAdapter.java
index 7d09d689f..41ce73c8c 100644
--- a/src/com/android/documentsui/dirlist/DocumentsAdapter.java
+++ b/src/com/android/documentsui/dirlist/DocumentsAdapter.java
@@ -36,8 +36,8 @@ import java.util.List;
 /**
  * DocumentsAdapter provides glue between a directory Model, and RecyclerView. We've
  * abstracted this a bit in order to decompose some specialized support
- * for adding dummy layout objects (@see SectionBreakDocumentsAdapter). Handling of the
- * dummy layout objects was error prone when interspersed with the core mode / adapter code.
+ * for adding stub layout objects (@see SectionBreakDocumentsAdapter). Handling of the
+ * stub layout objects was error prone when interspersed with the core mode / adapter code.
  *
  * @see ModelBackedDocumentsAdapter
  * @see DirectoryAddonsAdapter
diff --git a/src/com/android/documentsui/dirlist/DocumentsSwipeRefreshLayout.java b/src/com/android/documentsui/dirlist/DocumentsSwipeRefreshLayout.java
index a1963645b..4b66b857f 100644
--- a/src/com/android/documentsui/dirlist/DocumentsSwipeRefreshLayout.java
+++ b/src/com/android/documentsui/dirlist/DocumentsSwipeRefreshLayout.java
@@ -42,12 +42,12 @@ public class DocumentsSwipeRefreshLayout extends SwipeRefreshLayout {
     public DocumentsSwipeRefreshLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
 
-        final int[] styledAttrs = {android.R.attr.colorPrimary};
+        final int[] styledAttrs = {android.R.attr.colorAccent};
 
         TypedArray a = context.obtainStyledAttributes(styledAttrs);
         @ColorRes int colorId = a.getResourceId(0, -1);
         if (colorId == -1) {
-            Log.w(TAG, "Retrive colorPrimary colorId from theme fail, assign R.color.primary");
+            Log.w(TAG, "Retrieve colorAccent colorId from theme fail, assign R.color.primary");
             colorId = R.color.primary;
         }
         a.recycle();
diff --git a/src/com/android/documentsui/dirlist/DragStartListener.java b/src/com/android/documentsui/dirlist/DragStartListener.java
index 8fe087229..0adddcca8 100644
--- a/src/com/android/documentsui/dirlist/DragStartListener.java
+++ b/src/com/android/documentsui/dirlist/DragStartListener.java
@@ -48,7 +48,7 @@ import javax.annotation.Nullable;
  */
 interface DragStartListener {
 
-    static final DragStartListener DUMMY = new DragStartListener() {
+    DragStartListener STUB = new DragStartListener() {
         @Override
         public boolean onDragEvent(MotionEvent event) {
             return false;
diff --git a/src/com/android/documentsui/dirlist/GridDocumentHolder.java b/src/com/android/documentsui/dirlist/GridDocumentHolder.java
index 9e429688a..631298f12 100644
--- a/src/com/android/documentsui/dirlist/GridDocumentHolder.java
+++ b/src/com/android/documentsui/dirlist/GridDocumentHolder.java
@@ -89,7 +89,6 @@ final class GridDocumentHolder extends DocumentHolder {
         // But it should be an error to be set to selected && be disabled.
         if (!itemView.isEnabled()) {
             assert(!selected);
-            return;
         }
 
         super.setSelected(selected, animate);
diff --git a/src/com/android/documentsui/dirlist/ListDocumentHolder.java b/src/com/android/documentsui/dirlist/ListDocumentHolder.java
index 1bbeec1dd..f6a900236 100644
--- a/src/com/android/documentsui/dirlist/ListDocumentHolder.java
+++ b/src/com/android/documentsui/dirlist/ListDocumentHolder.java
@@ -22,7 +22,9 @@ import static com.android.documentsui.base.DocumentInfo.getCursorString;
 import android.content.Context;
 import android.database.Cursor;
 import android.graphics.Rect;
+import android.text.TextUtils;
 import android.text.format.Formatter;
+import android.util.Log;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
@@ -41,15 +43,20 @@ import com.android.documentsui.base.UserId;
 import com.android.documentsui.roots.RootCursorWrapper;
 import com.android.documentsui.ui.Views;
 
+import java.util.ArrayList;
 import java.util.function.Function;
 
 final class ListDocumentHolder extends DocumentHolder {
+    private static final String TAG = "ListDocumentHolder";
 
     private final TextView mTitle;
-    private final @Nullable LinearLayout mDetails;  // Container of date/size/summary
-    private final TextView mDate;
-    private final TextView mSize;
-    private final TextView mType;
+    private final @Nullable TextView mDate; // Non-null for tablets/sw720dp, null for other devices.
+    private final @Nullable TextView mSize; // Non-null for tablets/sw720dp, null for other devices.
+    private final @Nullable TextView mType; // Non-null for tablets/sw720dp, null for other devices.
+    // Container for date + size + summary, null only for tablets/sw720dp
+    private final @Nullable LinearLayout mDetails;
+    // TextView for date + size + summary, null only for tablets/sw720dp
+    private final @Nullable TextView mMetadataView;
     private final ImageView mIconMime;
     private final ImageView mIconThumb;
     private final ImageView mIconCheck;
@@ -75,6 +82,7 @@ final class ListDocumentHolder extends DocumentHolder {
         mSize = (TextView) itemView.findViewById(R.id.size);
         mDate = (TextView) itemView.findViewById(R.id.date);
         mType = (TextView) itemView.findViewById(R.id.file_type);
+        mMetadataView = (TextView) itemView.findViewById(R.id.metadata);
         // Warning: mDetails view doesn't exists in layout-sw720dp-land layout
         mDetails = (LinearLayout) itemView.findViewById(R.id.line2);
         mPreviewIcon = itemView.findViewById(R.id.preview_icon);
@@ -97,8 +105,7 @@ final class ListDocumentHolder extends DocumentHolder {
         }
 
         if (!itemView.isEnabled()) {
-            assert(!selected);
-            return;
+            assert (!selected);
         }
 
         super.setSelected(selected, animate);
@@ -183,12 +190,13 @@ final class ListDocumentHolder extends DocumentHolder {
 
     /**
      * Bind this view to the given document for display.
+     *
      * @param cursor Pointing to the item to be bound.
      * @param modelId The model ID of the item.
      */
     @Override
     public void bind(Cursor cursor, String modelId) {
-        assert(cursor != null);
+        assert (cursor != null);
 
         mModelId = modelId;
 
@@ -208,33 +216,50 @@ final class ListDocumentHolder extends DocumentHolder {
         mTitle.setText(mDoc.displayName, TextView.BufferType.SPANNABLE);
         mTitle.setVisibility(View.VISIBLE);
 
-
-        boolean hasDetails = false;
         if (mDoc.isDirectory()) {
             // Note, we don't show any details for any directory...ever.
-            hasDetails = false;
-        } else {
-            if (mDoc.lastModified > 0) {
-                hasDetails = true;
-                mDate.setText(Shared.formatTime(mContext, mDoc.lastModified));
-            } else {
-                mDate.setText(null);
+            if (mDetails != null) {
+                // Non-tablets
+                mDetails.setVisibility(View.GONE);
             }
-
-            if (mDoc.size > -1) {
-                hasDetails = true;
-                mSize.setVisibility(View.VISIBLE);
-                mSize.setText(Formatter.formatFileSize(mContext, mDoc.size));
+        } else {
+            // For tablets metadata is provided in columns mDate, mSize, mType.
+            // For other devices mMetadataView consolidates the metadata info.
+            if (mMetadataView != null) {
+                // Non-tablets
+                boolean hasDetails = false;
+                ArrayList<String> metadataList = new ArrayList<>();
+                if (mDoc.lastModified > 0) {
+                    hasDetails = true;
+                    metadataList.add(Shared.formatTime(mContext, mDoc.lastModified));
+                }
+                if (mDoc.size > -1) {
+                    hasDetails = true;
+                    metadataList.add(Formatter.formatFileSize(mContext, mDoc.size));
+                }
+                metadataList.add(mFileTypeLookup.lookup(mDoc.mimeType));
+                mMetadataView.setText(TextUtils.join(", ", metadataList));
+                if (mDetails != null) {
+                    mDetails.setVisibility(hasDetails ? View.VISIBLE : View.GONE);
+                } else {
+                    Log.w(TAG, "mDetails is unexpectedly null for non-tablet devices!");
+                }
             } else {
-                mSize.setVisibility(View.INVISIBLE);
+                // Tablets
+                if (mDoc.lastModified > 0) {
+                    mDate.setVisibility(View.VISIBLE);
+                    mDate.setText(Shared.formatTime(mContext, mDoc.lastModified));
+                } else {
+                    mDate.setVisibility(View.INVISIBLE);
+                }
+                if (mDoc.size > -1) {
+                    mSize.setVisibility(View.VISIBLE);
+                    mSize.setText(Formatter.formatFileSize(mContext, mDoc.size));
+                } else {
+                    mSize.setVisibility(View.INVISIBLE);
+                }
+                mType.setText(mFileTypeLookup.lookup(mDoc.mimeType));
             }
-
-            mType.setText(mFileTypeLookup.lookup(mDoc.mimeType));
-        }
-
-        // mDetails view doesn't exists in layout-sw720dp-land layout
-        if (mDetails != null) {
-            mDetails.setVisibility(hasDetails ? View.VISIBLE : View.GONE);
         }
 
         // TODO: Add document debug info
diff --git a/src/com/android/documentsui/dirlist/RenameDocumentFragment.java b/src/com/android/documentsui/dirlist/RenameDocumentFragment.java
index f46c4e54f..12873a218 100644
--- a/src/com/android/documentsui/dirlist/RenameDocumentFragment.java
+++ b/src/com/android/documentsui/dirlist/RenameDocumentFragment.java
@@ -158,16 +158,6 @@ public class RenameDocumentFragment extends DialogFragment {
     }
 
     /**
-     * Validates if string is a proper document name.
-     * Checks if string is not empty. More rules might be added later.
-     * @param docName string representing document name
-     * @returns true if string is a valid name.
-     **/
-    private boolean isValidDocumentName(String docName) {
-        return !docName.isEmpty();
-    }
-
-    /**
      * Fills text field with the file name and selects the name without extension.
      *
      * @param editText text field to be filled
@@ -193,17 +183,13 @@ public class RenameDocumentFragment extends DialogFragment {
 
         if (newDisplayName.equals(mDocument.displayName)) {
             mDialog.dismiss();
-        } else if (!isValidDocumentName(newDisplayName)) {
-            Log.w(TAG, "Failed to rename file - invalid name:" + newDisplayName);
-            mRenameInputWrapper.setError(getContext().getString(R.string.rename_error));
-            Metrics.logRenameFileError();
-        } else if (activity.getInjector().getModel().hasFileWithName(newDisplayName)){
+        } else if (newDisplayName.isEmpty()) {
+            mRenameInputWrapper.setError(getContext().getString(R.string.missing_rename_error));
+        } else if (activity.getInjector().getModel().hasFileWithName(newDisplayName)) {
             mRenameInputWrapper.setError(getContext().getString(R.string.name_conflict));
             selectFileName(mEditText);
-            Metrics.logRenameFileError();
         } else {
             new RenameDocumentsTask(activity, newDisplayName).execute(mDocument);
-
             if (mDialog != null) {
                 mDialog.dismiss();
             }
diff --git a/src/com/android/documentsui/files/FilesActivity.java b/src/com/android/documentsui/files/FilesActivity.java
index 1afb38eac..7c09811c9 100644
--- a/src/com/android/documentsui/files/FilesActivity.java
+++ b/src/com/android/documentsui/files/FilesActivity.java
@@ -37,7 +37,6 @@ import com.android.documentsui.ActionModeController;
 import com.android.documentsui.BaseActivity;
 import com.android.documentsui.DocsSelectionHelper;
 import com.android.documentsui.DocumentsApplication;
-import com.android.documentsui.DummyProfileTabsAddons;
 import com.android.documentsui.FocusManager;
 import com.android.documentsui.Injector;
 import com.android.documentsui.MenuManager.DirectoryDetails;
@@ -49,6 +48,7 @@ import com.android.documentsui.ProviderExecutor;
 import com.android.documentsui.R;
 import com.android.documentsui.SharedInputHandler;
 import com.android.documentsui.ShortcutsUpdater;
+import com.android.documentsui.StubProfileTabsAddons;
 import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.base.Features;
 import com.android.documentsui.base.RootInfo;
@@ -76,7 +76,7 @@ public class FilesActivity extends BaseActivity implements AbstractActionHandler
     private Injector<ActionHandler<FilesActivity>> mInjector;
     private ActivityInputHandler mActivityInputHandler;
     private SharedInputHandler mSharedInputHandler;
-    private final ProfileTabsAddons mProfileTabsAddonsStub = new DummyProfileTabsAddons();
+    private final ProfileTabsAddons mProfileTabsAddonsStub = new StubProfileTabsAddons();
 
     public FilesActivity() {
         super(R.layout.files_activity, TAG);
@@ -132,6 +132,7 @@ public class FilesActivity extends BaseActivity implements AbstractActionHandler
         mInjector.actionModeController = new ActionModeController(
                 this,
                 mInjector.selectionMgr,
+                mNavigator,
                 mInjector.menuManager,
                 mInjector.messages);
 
@@ -150,7 +151,7 @@ public class FilesActivity extends BaseActivity implements AbstractActionHandler
 
         mInjector.searchManager = mSearchManager;
 
-        // No profile tabs will be shown on FilesActivity. Use a dummy to avoid unnecessary
+        // No profile tabs will be shown on FilesActivity. Use a stub to avoid unnecessary
         // operations.
         mInjector.profileTabsController = new ProfileTabsController(
                 mInjector.selectionMgr,
diff --git a/src/com/android/documentsui/inspector/DebugView.java b/src/com/android/documentsui/inspector/DebugView.java
index ffd4b7e05..908d19242 100644
--- a/src/com/android/documentsui/inspector/DebugView.java
+++ b/src/com/android/documentsui/inspector/DebugView.java
@@ -27,8 +27,8 @@ import androidx.annotation.StringRes;
 
 import com.android.documentsui.R;
 import com.android.documentsui.base.DocumentInfo;
-import com.android.documentsui.base.DummyLookup;
 import com.android.documentsui.base.Lookup;
+import com.android.documentsui.base.StubLookup;
 import com.android.documentsui.inspector.InspectorController.DebugDisplay;
 
 import java.text.NumberFormat;
@@ -47,7 +47,7 @@ public class DebugView extends TableView implements DebugDisplay {
 
     private final Context mContext;
     private final Resources mRes;
-    private Lookup<String, Executor> mExecutors = new DummyLookup<>();
+    private Lookup<String, Executor> mExecutors = new StubLookup<>();
 
     public DebugView(Context context) {
         this(context, null);
diff --git a/src/com/android/documentsui/picker/PickActivity.java b/src/com/android/documentsui/picker/PickActivity.java
index 5328c640e..c2fbd50a0 100644
--- a/src/com/android/documentsui/picker/PickActivity.java
+++ b/src/com/android/documentsui/picker/PickActivity.java
@@ -121,6 +121,7 @@ public class PickActivity extends BaseActivity implements ActionHandler.Addons {
         mInjector.actionModeController = new ActionModeController(
                 this,
                 mInjector.selectionMgr,
+                mNavigator,
                 mInjector.menuManager,
                 mInjector.messages);
 
diff --git a/src/com/android/documentsui/picker/PickFragment.java b/src/com/android/documentsui/picker/PickFragment.java
index d7bd9277e..e9610a510 100644
--- a/src/com/android/documentsui/picker/PickFragment.java
+++ b/src/com/android/documentsui/picker/PickFragment.java
@@ -98,7 +98,7 @@ public class PickFragment extends Fragment {
         final PickFragment fragment = new PickFragment();
         final FragmentTransaction ft = fm.beginTransaction();
         ft.replace(R.id.container_save, fragment, TAG);
-        ft.commitAllowingStateLoss();
+        ft.commitNowAllowingStateLoss();
     }
 
     public static PickFragment get(FragmentManager fm) {
diff --git a/src/com/android/documentsui/queries/SearchChipViewManager.java b/src/com/android/documentsui/queries/SearchChipViewManager.java
index ebda22bf3..f80a3a7fa 100644
--- a/src/com/android/documentsui/queries/SearchChipViewManager.java
+++ b/src/com/android/documentsui/queries/SearchChipViewManager.java
@@ -24,6 +24,7 @@ import android.provider.DocumentsContract;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.accessibility.AccessibilityEvent;
 import android.widget.HorizontalScrollView;
 
 import androidx.annotation.NonNull;
@@ -35,6 +36,7 @@ import com.android.documentsui.MetricConsts;
 import com.android.documentsui.R;
 import com.android.documentsui.base.MimeTypes;
 import com.android.documentsui.base.Shared;
+import com.android.documentsui.util.VersionUtils;
 
 import com.google.android.material.chip.Chip;
 import com.google.common.primitives.Ints;
@@ -96,9 +98,11 @@ public class SearchChipViewManager {
     static {
         sMimeTypesChipItems.put(TYPE_IMAGES,
                 new SearchChipData(TYPE_IMAGES, R.string.chip_title_images, IMAGES_MIMETYPES));
-        sMimeTypesChipItems.put(TYPE_DOCUMENTS,
-                new SearchChipData(TYPE_DOCUMENTS, R.string.chip_title_documents,
-                        DOCUMENTS_MIMETYPES));
+        if (VersionUtils.isAtLeastR()) {
+            sMimeTypesChipItems.put(TYPE_DOCUMENTS,
+                    new SearchChipData(TYPE_DOCUMENTS, R.string.chip_title_documents,
+                            DOCUMENTS_MIMETYPES));
+        }
         sMimeTypesChipItems.put(TYPE_AUDIO,
                 new SearchChipData(TYPE_AUDIO, R.string.chip_title_audio, AUDIO_MIMETYPES));
         sMimeTypesChipItems.put(TYPE_VIDEOS,
@@ -395,7 +399,7 @@ public class SearchChipViewManager {
      * Reorder the chips in chip group. The checked chip has higher order.
      *
      * @param clickedChip the clicked chip, may be null.
-     * @param hasAnim if true, play move animation. Otherwise, not.
+     * @param hasAnim     if true, play move animation. Otherwise, not.
      */
     private void reorderCheckedChips(@Nullable Chip clickedChip, boolean hasAnim) {
         final ArrayList<Chip> chipList = new ArrayList<>();
@@ -421,9 +425,10 @@ public class SearchChipViewManager {
             return;
         }
 
-        final int chipSpacing = mChipGroup.getPaddingEnd();
+        final int chipSpacing = mChipGroup.getResources().getDimensionPixelSize(
+                R.dimen.search_chip_spacing);
         final boolean isRtl = mChipGroup.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL;
-        float lastX = isRtl ? mChipGroup.getWidth() - chipSpacing : chipSpacing;
+        float lastX = isRtl ? mChipGroup.getWidth() - chipSpacing / 2 : chipSpacing / 2;
 
         // remove all chips except current clicked chip to avoid losing
         // accessibility focus.
@@ -465,6 +470,10 @@ public class SearchChipViewManager {
             if (parent instanceof HorizontalScrollView) {
                 final int scrollToX = isRtl ? parent.getWidth() : 0;
                 ((HorizontalScrollView) parent).smoothScrollTo(scrollToX, 0);
+                if (mChipGroup.getChildCount() > 0) {
+                    mChipGroup.getChildAt(0)
+                            .sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
+                }
             }
         }
     }
diff --git a/src/com/android/documentsui/queries/SearchFragment.java b/src/com/android/documentsui/queries/SearchFragment.java
index 7f2e779bb..92cd91a3f 100644
--- a/src/com/android/documentsui/queries/SearchFragment.java
+++ b/src/com/android/documentsui/queries/SearchFragment.java
@@ -40,7 +40,7 @@ import com.android.documentsui.R;
 
 import java.util.List;
 
-public class SearchFragment extends Fragment{
+public class SearchFragment extends Fragment {
 
     private static final String TAG = "SearchFragment";
     private static final String KEY_QUERY = "query";
@@ -97,8 +97,8 @@ public class SearchFragment extends Fragment{
     }
 
     @Override
-    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
-        super.onActivityCreated(savedInstanceState);
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
 
         final BaseActivity activity = (BaseActivity) getActivity();
         final Injector injector = activity.getInjector();
@@ -121,14 +121,16 @@ public class SearchFragment extends Fragment{
         mListView.setAdapter(mAdapter);
         mListView.setOnItemClickListener(this::onHistoryItemClicked);
 
-        View toolbar = getActivity().findViewById(R.id.toolbar_background_layout);
-        if (toolbar != null) {
-            // Align top with the bottom of search bar.
+        View toolbar = getActivity().findViewById(R.id.toolbar);
+        View collapsingBarLayout = getActivity().findViewById(R.id.collapsing_toolbar);
+        if (toolbar != null && collapsingBarLayout != null) {
+            // If collapsingBarLayout is used (i.e. not in Tablet mode),
+            // need to align top with the bottom of search bar.
             FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(
                     ViewGroup.LayoutParams.MATCH_PARENT,
                     ViewGroup.LayoutParams.MATCH_PARENT);
             layoutParams.setMargins(0, getResources().getDimensionPixelSize(
-                    R.dimen.action_bar_space_height), 0, 0);
+                    R.dimen.action_bar_margin) + toolbar.getLayoutParams().height, 0, 0);
             getView().setLayoutParams(layoutParams);
         }
 
@@ -150,7 +152,7 @@ public class SearchFragment extends Fragment{
         final String item = mHistoryList.get(position);
         mSearchViewManager.setHistorySearch();
         mSearchViewManager.setCurrentSearch(item);
-        mSearchViewManager.restoreSearch(true);
+        mSearchViewManager.restoreSearch(/* keepFocus= */ false);
     }
 
     private void dismiss() {
diff --git a/src/com/android/documentsui/queries/SearchViewManager.java b/src/com/android/documentsui/queries/SearchViewManager.java
index e94e900e8..b1016952f 100644
--- a/src/com/android/documentsui/queries/SearchViewManager.java
+++ b/src/com/android/documentsui/queries/SearchViewManager.java
@@ -333,8 +333,6 @@ public class SearchViewManager implements
     public boolean cancelSearch() {
         if (mSearchView != null && (isExpanded() || isSearching())) {
             cancelQueuedSearch();
-            // If the query string is not empty search view won't get iconified
-            mSearchView.setQuery("", false);
 
             if (mFullBar) {
                 onClose();
@@ -420,6 +418,11 @@ public class SearchViewManager implements
 
         // Refresh the directory if a search was done
         if (mCurrentSearch != null || mChipViewManager.hasCheckedItems()) {
+            // Make sure SearchFragment was dismissed.
+            if (mFragmentManager != null) {
+                SearchFragment.dismissFragment(mFragmentManager);
+            }
+
             // Clear checked chips
             mChipViewManager.clearCheckedChips();
             mCurrentSearch = null;
diff --git a/src/com/android/documentsui/roots/ProvidersCache.java b/src/com/android/documentsui/roots/ProvidersCache.java
index f35d05e2f..ebd54972e 100644
--- a/src/com/android/documentsui/roots/ProvidersCache.java
+++ b/src/com/android/documentsui/roots/ProvidersCache.java
@@ -62,6 +62,7 @@ import com.android.documentsui.base.UserId;
 
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.Multimap;
+import com.google.common.util.concurrent.MoreExecutors;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -72,6 +73,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
@@ -90,6 +95,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
         // ArchivesProvider doesn't support any roots.
         add(ArchivesProvider.AUTHORITY);
     }};
+    private static final int FIRST_LOAD_TIMEOUT_MS = 5000;
 
     private final Context mContext;
 
@@ -111,6 +117,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
     private Multimap<UserAuthority, RootInfo> mRoots = ArrayListMultimap.create();
     @GuardedBy("mLock")
     private HashSet<UserAuthority> mStoppedAuthorities = new HashSet<>();
+    private final Semaphore mMultiProviderUpdateTaskSemaphore = new Semaphore(1);
 
     @GuardedBy("mObservedAuthoritiesDetails")
     private final Map<UserAuthority, PackageDetails> mObservedAuthoritiesDetails = new HashMap<>();
@@ -205,13 +212,16 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
             assert (recentRoot.availableBytes == -1);
         }
 
-        new UpdateTask(forceRefreshAll, null, callback).executeOnExecutor(
+        new MultiProviderUpdateTask(forceRefreshAll, null, callback).executeOnExecutor(
                 AsyncTask.THREAD_POOL_EXECUTOR);
     }
 
     public void updatePackageAsync(UserId userId, String packageName) {
-        new UpdateTask(false, new UserPackage(userId, packageName),
-                /* callback= */ null).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
+        new MultiProviderUpdateTask(
+                /* forceRefreshAll= */ false,
+                new UserPackage(userId, packageName),
+                /* callback= */ null)
+                .executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
     }
 
     public void updateAuthorityAsync(UserId userId, String authority) {
@@ -235,7 +245,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
     }
 
     /**
-     * Block until the first {@link UpdateTask} pass has finished.
+     * Block until the first {@link MultiProviderUpdateTask} pass has finished.
      *
      * @return {@code true} if cached roots is ready to roll, otherwise
      * {@code false} if we timed out while waiting.
@@ -243,7 +253,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
     private boolean waitForFirstLoad() {
         boolean success = false;
         try {
-            success = mFirstLoad.await(15, TimeUnit.SECONDS);
+            success = mFirstLoad.await(FIRST_LOAD_TIMEOUT_MS, TimeUnit.MILLISECONDS);
         } catch (InterruptedException e) {
         }
         if (!success) {
@@ -254,7 +264,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
 
     /**
      * Load roots from authorities that are in stopped state. Normal
-     * {@link UpdateTask} passes ignore stopped applications.
+     * {@link MultiProviderUpdateTask} passes ignore stopped applications.
      */
     private void loadStoppedAuthorities() {
         synchronized (mLock) {
@@ -266,7 +276,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
     }
 
     /**
-     * Load roots from a stopped authority. Normal {@link UpdateTask} passes
+     * Load roots from a stopped authority. Normal {@link MultiProviderUpdateTask} passes
      * ignore stopped applications.
      */
     private void loadStoppedAuthority(UserAuthority userAuthority) {
@@ -433,7 +443,7 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
         waitForFirstLoad();
         loadStoppedAuthorities();
         synchronized (mLock) {
-            return mRoots.values();
+            return new HashSet<>(mRoots.values());
         }
     }
 
@@ -485,15 +495,17 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
         Log.i(TAG, output.toString());
     }
 
-    private class UpdateTask extends AsyncTask<Void, Void, Void> {
+    private class MultiProviderUpdateTask extends AsyncTask<Void, Void, Void> {
         private final boolean mForceRefreshAll;
         @Nullable
         private final UserPackage mForceRefreshUserPackage;
         @Nullable
         private final Runnable mCallback;
 
-        private final Multimap<UserAuthority, RootInfo> mTaskRoots = ArrayListMultimap.create();
-        private final HashSet<UserAuthority> mTaskStoppedAuthorities = new HashSet<>();
+        @GuardedBy("mLock")
+        private Multimap<UserAuthority, RootInfo> mLocalRoots = ArrayListMultimap.create();
+        @GuardedBy("mLock")
+        private HashSet<UserAuthority> mLocalStoppedAuthorities = new HashSet<>();
 
         /**
          * Create task to update roots cache.
@@ -504,7 +516,9 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
          *            values for this specific user package should be ignored.
          * @param callback when non-null, it will be invoked after the task is executed.
          */
-        UpdateTask(boolean forceRefreshAll, @Nullable UserPackage forceRefreshUserPackage,
+        MultiProviderUpdateTask(
+                boolean forceRefreshAll,
+                @Nullable UserPackage forceRefreshUserPackage,
                 @Nullable Runnable callback) {
             mForceRefreshAll = forceRefreshAll;
             mForceRefreshUserPackage = forceRefreshUserPackage;
@@ -513,12 +527,25 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
 
         @Override
         protected Void doInBackground(Void... params) {
+            if (!mMultiProviderUpdateTaskSemaphore.tryAcquire()) {
+                // Abort, since previous update task is still running.
+                return null;
+            }
+
+            int previousPriority = Thread.currentThread().getPriority();
+            Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
+
             final long start = SystemClock.elapsedRealtime();
 
             for (UserId userId : mUserIdManager.getUserIds()) {
                 final RootInfo recents = createOrGetRecentsRoot(userId);
-                mTaskRoots.put(new UserAuthority(recents.userId, recents.authority), recents);
+                synchronized (mLock) {
+                    mLocalRoots.put(new UserAuthority(recents.userId, recents.authority), recents);
+                }
+            }
 
+            List<SingleProviderUpdateTaskInfo> taskInfos = new ArrayList<>();
+            for (UserId userId : mUserIdManager.getUserIds()) {
                 final PackageManager pm = userId.getPackageManager(mContext);
                 // Pick up provider with action string
                 final Intent intent = new Intent(DocumentsContract.PROVIDER_INTERFACE);
@@ -526,25 +553,55 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
                 for (ResolveInfo info : providers) {
                     ProviderInfo providerInfo = info.providerInfo;
                     if (providerInfo.authority != null) {
-                        handleDocumentsProvider(providerInfo, userId);
+                        taskInfos.add(new SingleProviderUpdateTaskInfo(providerInfo, userId));
                     }
                 }
             }
 
+            if (!taskInfos.isEmpty()) {
+                CountDownLatch updateTaskInternalCountDown = new CountDownLatch(taskInfos.size());
+                ExecutorService executor = MoreExecutors.getExitingExecutorService(
+                        (ThreadPoolExecutor) Executors.newCachedThreadPool());
+                for (SingleProviderUpdateTaskInfo taskInfo: taskInfos) {
+                    executor.submit(() ->
+                            startSingleProviderUpdateTask(
+                                    taskInfo.providerInfo,
+                                    taskInfo.userId,
+                                    updateTaskInternalCountDown));
+                }
+
+                // Block until all SingleProviderUpdateTask threads finish executing.
+                // Use a shorter timeout for first load since it could block picker UI.
+                long timeoutMs = mFirstLoadDone ? 15000 : FIRST_LOAD_TIMEOUT_MS;
+                boolean success = false;
+                try {
+                    success = updateTaskInternalCountDown.await(timeoutMs, TimeUnit.MILLISECONDS);
+                } catch (InterruptedException e) {
+                }
+                if (!success) {
+                    Log.w(TAG, "Timeout executing update task!");
+                }
+            }
+
             final long delta = SystemClock.elapsedRealtime() - start;
-            if (VERBOSE) Log.v(TAG,
-                    "Update found " + mTaskRoots.size() + " roots in " + delta + "ms");
             synchronized (mLock) {
                 mFirstLoadDone = true;
                 if (mBootCompletedResult != null) {
                     mBootCompletedResult.finish();
                     mBootCompletedResult = null;
                 }
-                mRoots = mTaskRoots;
-                mStoppedAuthorities = mTaskStoppedAuthorities;
+                mRoots = mLocalRoots;
+                mStoppedAuthorities = mLocalStoppedAuthorities;
+            }
+            if (VERBOSE) {
+                Log.v(TAG, "Update found " + mLocalRoots.size() + " roots in " + delta + "ms");
             }
+
             mFirstLoad.countDown();
             LocalBroadcastManager.getInstance(mContext).sendBroadcast(new Intent(BROADCAST_ACTION));
+            mMultiProviderUpdateTaskSemaphore.release();
+
+            Thread.currentThread().setPriority(previousPriority);
             return null;
         }
 
@@ -555,6 +612,17 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
             }
         }
 
+        private void startSingleProviderUpdateTask(
+                ProviderInfo providerInfo,
+                UserId userId,
+                CountDownLatch updateCountDown) {
+            int previousPriority = Thread.currentThread().getPriority();
+            Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
+            handleDocumentsProvider(providerInfo, userId);
+            updateCountDown.countDown();
+            Thread.currentThread().setPriority(previousPriority);
+        }
+
         private void handleDocumentsProvider(ProviderInfo info, UserId userId) {
             UserAuthority userAuthority = new UserAuthority(userId, info.authority);
             // Ignore stopped packages for now; we might query them
@@ -563,16 +631,20 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
                 if (VERBOSE) {
                     Log.v(TAG, "Ignoring stopped authority " + info.authority + ", user " + userId);
                 }
-                mTaskStoppedAuthorities.add(userAuthority);
+                synchronized (mLock) {
+                    mLocalStoppedAuthorities.add(userAuthority);
+                }
                 return;
             }
 
             final boolean forceRefresh = mForceRefreshAll
-                    || Objects.equals(new UserPackage(userId, info.packageName),
-                    mForceRefreshUserPackage);
-            mTaskRoots.putAll(userAuthority, loadRootsForAuthority(userAuthority, forceRefresh));
+                    || Objects.equals(
+                    new UserPackage(userId, info.packageName), mForceRefreshUserPackage);
+            synchronized (mLock) {
+                mLocalRoots.putAll(userAuthority,
+                        loadRootsForAuthority(userAuthority, forceRefresh));
+            }
         }
-
     }
 
     private static class UserAuthority {
@@ -611,6 +683,16 @@ public class ProvidersCache implements ProvidersAccess, LookupApplicationName {
         }
     }
 
+    private static class SingleProviderUpdateTaskInfo {
+        private final ProviderInfo providerInfo;
+        private final UserId userId;
+
+        SingleProviderUpdateTaskInfo(ProviderInfo providerInfo, UserId userId) {
+            this.providerInfo = providerInfo;
+            this.userId = userId;
+        }
+    }
+
     private static class PackageDetails {
         private String applicationName;
         private String packageName;
diff --git a/src/com/android/documentsui/services/CompressJob.java b/src/com/android/documentsui/services/CompressJob.java
index 1f2ea4436..e9ba6e4c8 100644
--- a/src/com/android/documentsui/services/CompressJob.java
+++ b/src/com/android/documentsui/services/CompressJob.java
@@ -16,6 +16,8 @@
 
 package com.android.documentsui.services;
 
+import static android.content.ContentResolver.wrap;
+
 import static com.android.documentsui.services.FileOperationService.OPERATION_MOVE;
 
 import android.app.Notification;
@@ -45,6 +47,8 @@ final class CompressJob extends CopyJob {
     private static final String TAG = "CompressJob";
     private static final String NEW_ARCHIVE_EXTENSION = ".zip";
 
+    private Uri mArchiveUri;
+
     /**
      * Moves files to a destination identified by {@code destination}.
      * Performs most work by delegating to CopyJob, then deleting
@@ -99,17 +103,16 @@ final class CompressJob extends CopyJob {
             displayName = service.getString(R.string.new_archive_file_name, NEW_ARCHIVE_EXTENSION);
         }
 
-        Uri archiveUri;
         try {
-            archiveUri = DocumentsContract.createDocument(
-                resolver, mDstInfo.derivedUri, "application/zip", displayName);
+            mArchiveUri = DocumentsContract.createDocument(
+                    resolver, mDstInfo.derivedUri, "application/zip", displayName);
         } catch (Exception e) {
-            archiveUri = null;
+            mArchiveUri = null;
         }
 
         try {
             mDstInfo = DocumentInfo.fromUri(resolver, ArchivesProvider.buildUriForArchive(
-                    archiveUri, ParcelFileDescriptor.MODE_WRITE_ONLY), UserId.DEFAULT_USER);
+                    mArchiveUri, ParcelFileDescriptor.MODE_WRITE_ONLY), UserId.DEFAULT_USER);
             ArchivesProvider.acquireArchive(getClient(mDstInfo), mDstInfo.derivedUri);
         } catch (FileNotFoundException e) {
             Log.e(TAG, "Failed to create dstInfo.", e);
@@ -132,7 +135,14 @@ final class CompressJob extends CopyJob {
             Log.e(TAG, "Failed to release the archive.");
         }
 
-        // TODO: Remove the archive file in case of an error.
+        // Remove the archive file in case of an error.
+        try {
+            if (!isFinished() || isCanceled()) {
+                DocumentsContract.deleteDocument(wrap(getClient(mArchiveUri)), mArchiveUri);
+            }
+        } catch (RemoteException | FileNotFoundException e) {
+            Log.w(TAG, "Failed to cleanup after compress error: " + mDstInfo.toString(), e);
+        }
 
         super.finish();
     }
diff --git a/src/com/android/documentsui/services/CopyJob.java b/src/com/android/documentsui/services/CopyJob.java
index f81966eb6..c972c33ef 100644
--- a/src/com/android/documentsui/services/CopyJob.java
+++ b/src/com/android/documentsui/services/CopyJob.java
@@ -187,7 +187,8 @@ class CopyJob extends ResolvedResourcesJob {
                 .setContentText(service.getString(
                         R.string.notification_touch_for_details))
                 .setContentIntent(PendingIntent.getActivity(appContext, 0, navigateIntent,
-                        PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT))
+                        PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT
+                                | PendingIntent.FLAG_IMMUTABLE))
                 .setCategory(Notification.CATEGORY_ERROR)
                 .setSmallIcon(R.drawable.ic_menu_copy)
                 .setAutoCancel(true);
diff --git a/src/com/android/documentsui/services/FileOperationService.java b/src/com/android/documentsui/services/FileOperationService.java
index ca6166a7c..c7be5f4fc 100644
--- a/src/com/android/documentsui/services/FileOperationService.java
+++ b/src/com/android/documentsui/services/FileOperationService.java
@@ -18,7 +18,6 @@ package com.android.documentsui.services;
 
 import static com.android.documentsui.base.SharedMinimal.DEBUG;
 
-import androidx.annotation.IntDef;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
@@ -29,9 +28,11 @@ import android.os.Handler;
 import android.os.IBinder;
 import android.os.PowerManager;
 import android.os.UserManager;
-import androidx.annotation.VisibleForTesting;
 import android.util.Log;
 
+import androidx.annotation.IntDef;
+import androidx.annotation.VisibleForTesting;
+
 import com.android.documentsui.R;
 import com.android.documentsui.base.Features;
 
@@ -97,7 +98,9 @@ public class FileOperationService extends Service implements Job.Listener {
 
     static final String NOTIFICATION_CHANNEL_ID = "channel_id";
 
-    private static final int POOL_SIZE = 2;  // "pool size", not *max* "pool size".
+    // This is a temporary solution, we will gray out the UI when a transaction is in progress to
+    // not enable users to make a transaction.
+    private static final int POOL_SIZE = 1;  // Allow only 1 executor operation
 
     @VisibleForTesting static final int NOTIFICATION_ID_PROGRESS = 1;
     private static final int NOTIFICATION_ID_FAILURE = 2;
diff --git a/src/com/android/documentsui/services/Job.java b/src/com/android/documentsui/services/Job.java
index 5659c06bd..71f0ae861 100644
--- a/src/com/android/documentsui/services/Job.java
+++ b/src/com/android/documentsui/services/Job.java
@@ -310,7 +310,8 @@ abstract public class Job implements Runnable {
                         failureCount, failureCount))
                 .setContentText(service.getString(R.string.notification_touch_for_details))
                 .setContentIntent(PendingIntent.getActivity(appContext, 0, navigateIntent,
-                        PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT))
+                        PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT
+                        | PendingIntent.FLAG_MUTABLE))
                 .setCategory(Notification.CATEGORY_ERROR)
                 .setSmallIcon(icon)
                 .setAutoCancel(true);
@@ -327,7 +328,8 @@ abstract public class Job implements Runnable {
                 .setContentTitle(title)
                 .setContentIntent(
                         PendingIntent.getActivity(appContext, 0,
-                                buildNavigateIntent(INTENT_TAG_PROGRESS), 0))
+                                buildNavigateIntent(INTENT_TAG_PROGRESS),
+                                PendingIntent.FLAG_IMMUTABLE))
                 .setCategory(Notification.CATEGORY_PROGRESS)
                 .setSmallIcon(icon)
                 .setOngoing(true);
@@ -341,7 +343,8 @@ abstract public class Job implements Runnable {
                         service,
                         0,
                         cancelIntent,
-                        PendingIntent.FLAG_ONE_SHOT | PendingIntent.FLAG_CANCEL_CURRENT));
+                        PendingIntent.FLAG_ONE_SHOT | PendingIntent.FLAG_CANCEL_CURRENT
+                        | PendingIntent.FLAG_MUTABLE));
 
         return progressBuilder;
     }
diff --git a/src/com/android/documentsui/sidebar/RootItem.java b/src/com/android/documentsui/sidebar/RootItem.java
index 9af396e4c..a0a3210f8 100644
--- a/src/com/android/documentsui/sidebar/RootItem.java
+++ b/src/com/android/documentsui/sidebar/RootItem.java
@@ -210,13 +210,13 @@ public class RootItem extends Item {
     }
 
     /**
-     * Creates a dummy root item for a user. A dummy root item is used as a place holder when
+     * Creates a stub root item for a user. A stub root item is used as a place holder when
      * there is no such root available. We can therefore show the item on the UI.
      */
-    public static RootItem createDummyItem(RootItem item, UserId targetUser) {
-        RootInfo dummyRootInfo = RootInfo.copyRootInfo(item.root);
-        dummyRootInfo.userId = targetUser;
-        RootItem dummy = new RootItem(dummyRootInfo, item.mActionHandler, item.mMaybeShowBadge);
-        return dummy;
+    public static RootItem createStubItem(RootItem item, UserId targetUser) {
+        RootInfo stubRootInfo = RootInfo.copyRootInfo(item.root);
+        stubRootInfo.userId = targetUser;
+        RootItem stub = new RootItem(stubRootInfo, item.mActionHandler, item.mMaybeShowBadge);
+        return stub;
     }
 }
diff --git a/src/com/android/documentsui/sidebar/RootItemListBuilder.java b/src/com/android/documentsui/sidebar/RootItemListBuilder.java
index 4bdce15f3..b29bd0d87 100644
--- a/src/com/android/documentsui/sidebar/RootItemListBuilder.java
+++ b/src/com/android/documentsui/sidebar/RootItemListBuilder.java
@@ -37,7 +37,7 @@ import java.util.List;
  * selected user.
  *
  * <p>If no root of the selected user was added but that of the other user was added,
- * a dummy root of that root for the selected user will be generated.
+ * a stub root of that root for the selected user will be generated.
  *
  * <p>The builder group the roots using {@link Item#stringId} as key.
  *
@@ -45,9 +45,9 @@ import java.util.List;
  * itemC[10], itemX[0],itemY[10] where root itemX, itemY do not support cross profile.
  *
  * <p>When the selected user is user 0, {@link #getList()} returns itemA[0], itemB[0],
- * dummyC[0], itemX[0], itemY[10].
+ * stubC[0], itemX[0], itemY[10].
  *
- * <p>When the selected user is user 10, {@link #getList()} returns itemA[10], dummyB[10],
+ * <p>When the selected user is user 10, {@link #getList()} returns itemA[10], stubB[10],
  * itemC[10], itemX[0], itemY[10].
  */
 class RootItemListBuilder {
@@ -87,7 +87,7 @@ class RootItemListBuilder {
             return items;
         }
 
-        // If the root supports cross-profile, we return the added root or create a dummy root if
+        // If the root supports cross-profile, we return the added root or create a stub root if
         // it was not added for the selected user.
         for (RootItem item : items) {
             if (item.userId.equals(mSelectedUser)) {
@@ -96,6 +96,6 @@ class RootItemListBuilder {
             }
         }
 
-        return Collections.singletonList(RootItem.createDummyItem(testRootItem, mSelectedUser));
+        return Collections.singletonList(RootItem.createStubItem(testRootItem, mSelectedUser));
     }
 }
diff --git a/src/com/android/documentsui/sidebar/SpacerItem.java b/src/com/android/documentsui/sidebar/SpacerItem.java
index d0f49c9d1..44dd75cbb 100644
--- a/src/com/android/documentsui/sidebar/SpacerItem.java
+++ b/src/com/android/documentsui/sidebar/SpacerItem.java
@@ -25,7 +25,7 @@ import com.android.documentsui.R;
 import com.android.documentsui.base.UserId;
 
 /**
- * Dummy {@link Item} for dividers between different types of {@link Item}s.
+ * Stub {@link Item} for dividers between different types of {@link Item}s.
  */
 class SpacerItem extends Item {
     private static final String TAG = "SpacerItem";
diff --git a/src/com/android/documentsui/util/VersionUtils.java b/src/com/android/documentsui/util/VersionUtils.java
index 58ae3cdca..aba6374ec 100644
--- a/src/com/android/documentsui/util/VersionUtils.java
+++ b/src/com/android/documentsui/util/VersionUtils.java
@@ -27,10 +27,19 @@ public class VersionUtils {
     }
 
     /**
-     * Returns whether the device is running on the Android R or newer.
+     * Returns whether the device is running on Android R or newer.
      */
     public static boolean isAtLeastR() {
-        return Build.VERSION.CODENAME.equals("R")
-                || (Build.VERSION.CODENAME.equals("REL") && Build.VERSION.SDK_INT >= 30);
+        return isAtLeastS() // Keep reference to isAtLeastS() so it's not stripped from test apk
+                || Build.VERSION.CODENAME.equals("R")
+                || Build.VERSION.SDK_INT >= 30;
+    }
+
+    /**
+     * Returns whether the device is running on Android S or newer.
+     */
+    public static boolean isAtLeastS() {
+        return Build.VERSION.CODENAME.equals("S")
+                || Build.VERSION.SDK_INT >= 31;
     }
 }