Fix 5948189 BUG BASH: action bar flashes during multi-select

This CL fixes the flashing by disabling MenuItem directly instead of setting null intent
to ShareActionProvider, so there won't be any "icons shrinking" effect that causes flashing.

The rest of the change is code refactoring. More comments are added and the final UI operations
are merged into one Runnable object.

Change-Id: I73843c1df6b7a9675176e1b3ae6a35cc1cb715fa

1 files changed, 50 insertions, 46 deletions

diff --git a/src/com/android/gallery3d/ui/ActionModeHandler.java b/src/com/android/gallery3d/ui/ActionModeHandler.java
index b96932ec2..f2093205f 100644
--- a/src/com/android/gallery3d/ui/ActionModeHandler.java
+++ b/src/com/android/gallery3d/ui/ActionModeHandler.java
@@ -173,55 +173,48 @@ public class ActionModeHandler implements ActionMode.Callback {
     // We cannot expand it because MenuExecuter executes it based on
     // the selection set instead of the expanded result.
     // e.g. LocalImage can be rotated but collections of them (LocalAlbum) can't.
-    private void updateMenuOptions(JobContext jc) {
-        ArrayList<Path> paths = mSelectionManager.getSelected(false);
-
+    private int computeMenuOptions(JobContext jc) {
+        ArrayList<Path> unexpandedPaths = mSelectionManager.getSelected(false);
+        if (unexpandedPaths.isEmpty()) {
+            // This happens when starting selection mode from overflow menu
+            // (instead of long press a media object)
+            return 0;
+        }
         int operation = MediaObject.SUPPORT_ALL;
         DataManager manager = mActivity.getDataManager();
         int type = 0;
-        for (Path path : paths) {
-            if (jc.isCancelled()) return;
+        for (Path path : unexpandedPaths) {
+            if (jc.isCancelled()) return 0;
             int support = manager.getSupportedOperations(path);
             type |= manager.getMediaType(path);
             operation &= support;
         }
 
-        final String mimeType = MenuExecutor.getMimeType(type);
-        if (paths.size() == 0) {
-            operation = 0;
-        } else if (paths.size() == 1) {
-            if (!GalleryUtils.isEditorAvailable((Context) mActivity, mimeType)) {
-                operation &= ~MediaObject.SUPPORT_EDIT;
-            }
-        } else {
-            operation &= SUPPORT_MULTIPLE_MASK;
+        switch (unexpandedPaths.size()) {
+            case 1:
+                final String mimeType = MenuExecutor.getMimeType(type);
+                if (!GalleryUtils.isEditorAvailable((Context) mActivity, mimeType)) {
+                    operation &= ~MediaObject.SUPPORT_EDIT;
+                }
+                break;
+            default:
+                operation &= SUPPORT_MULTIPLE_MASK;
         }
 
-        final int supportedOperation = operation;
-
-        mMainHandler.post(new Runnable() {
-            @Override
-            public void run() {
-                mMenuTask = null;
-                MenuExecutor.updateMenuOperation(mMenu, supportedOperation);
-            }
-        });
+        return operation;
     }
 
     // Share intent needs to expand the selection set so we can get URI of
     // each media item
-    private void updateSharingIntent(JobContext jc) {
-        if (mShareActionProvider == null) return;
-        ArrayList<Path> paths = mSelectionManager.getSelected(true);
-        if (paths.size() == 0) return;
-
+    private Intent computeSharingIntent(JobContext jc) {
+        ArrayList<Path> expandedPaths = mSelectionManager.getSelected(true);
+        if (expandedPaths.size() == 0) return null;
         final ArrayList<Uri> uris = new ArrayList<Uri>();
-
         DataManager manager = mActivity.getDataManager();
         int type = 0;
-
         final Intent intent = new Intent();
-        for (Path path : paths) {
+        for (Path path : expandedPaths) {
+            if (jc.isCancelled()) return null;
             int support = manager.getSupportedOperations(path);
             type |= manager.getMediaType(path);
 
@@ -241,15 +234,9 @@ public class ActionModeHandler implements ActionMode.Callback {
                 intent.putExtra(Intent.EXTRA_STREAM, uris.get(0));
             }
             intent.setType(mimeType);
-
-            mMainHandler.post(new Runnable() {
-                @Override
-                public void run() {
-                    Log.v(TAG, "Sharing intent is ready: action = " + intent.getAction());
-                    mShareActionProvider.setShareIntent(intent);
-                }
-            });
         }
+
+        return intent;
     }
 
     public void updateSupportedOperation(Path path, boolean selected) {
@@ -258,21 +245,38 @@ public class ActionModeHandler implements ActionMode.Callback {
     }
 
     public void updateSupportedOperation() {
+        // Interrupt previous unfinished task, mMenuTask is only accessed in main thread
         if (mMenuTask != null) {
             mMenuTask.cancel();
         }
 
         // Disable share action until share intent is in good shape
-        if (mShareActionProvider != null) {
-            Log.v(TAG, "Disable sharing until intent is ready");
-            mShareActionProvider.setShareIntent(null);
-        }
+        final MenuItem item = mShareActionProvider != null ?
+                mMenu.findItem(R.id.action_share) : null;
+        final boolean supportShare = item != null;
+        if (supportShare) item.setEnabled(false);
 
         // Generate sharing intent and update supported operations in the background
+        // The task can take a long time and be canceled in the mean time.
         mMenuTask = mActivity.getThreadPool().submit(new Job<Void>() {
-            public Void run(JobContext jc) {
-                updateMenuOptions(jc);
-                updateSharingIntent(jc);
+            public Void run(final JobContext jc) {
+                // Pass1: Deal with unexpanded media object list for menu operation.
+                final int operation = computeMenuOptions(jc);
+
+                // Pass2: Deal with expanded media object list for sharing operation.
+                final Intent intent = supportShare ? computeSharingIntent(jc) : null;
+                mMainHandler.post(new Runnable() {
+                    public void run() {
+                        mMenuTask = null;
+                        if (!jc.isCancelled()) {
+                            MenuExecutor.updateMenuOperation(mMenu, operation);
+                            if (supportShare) {
+                                item.setEnabled(true);
+                                mShareActionProvider.setShareIntent(intent);
+                            }
+                        }
+                    }
+                });
                 return null;
             }
         });