1 files changed, 48 insertions, 9 deletions

diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index dee15d0d7..d550edcd3 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -39,6 +39,7 @@ import android.graphics.Point;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.os.Build;
+import android.os.Bundle;
 import android.os.Handler;
 import android.os.UserHandle;
 import android.support.annotation.Nullable;
@@ -386,7 +387,13 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
     private void updateClearAllButtonAlpha() {
         if (mClearAllButton != null) {
             final float alpha = calculateClearAllButtonAlpha();
-            mIsClearAllButtonFullyRevealed = alpha == 1;
+            final boolean revealed = alpha == 1;
+            if (mIsClearAllButtonFullyRevealed != revealed) {
+                mIsClearAllButtonFullyRevealed = revealed;
+                mClearAllButton.setImportantForAccessibility(revealed ?
+                        IMPORTANT_FOR_ACCESSIBILITY_YES :
+                        IMPORTANT_FOR_ACCESSIBILITY_NO);
+            }
             mClearAllButton.setAlpha(alpha * mContentAlpha);
         }
     }
@@ -507,6 +514,7 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
         DeviceProfile dp = mActivity.getDeviceProfile();
         getTaskSize(dp, mTempRect);
 
+        // Keep this logic in sync with ActivityControlHelper.getTranslationYForQuickScrub.
         mTempRect.top -= mTaskTopMargin;
         setPadding(mTempRect.left - mInsets.left, mTempRect.top - mInsets.top,
                 dp.availableWidthPx + mInsets.left - mTempRect.right,
@@ -1285,7 +1293,30 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
     }
 
     @Override
+    public boolean performAccessibilityAction(int action, Bundle arguments) {
+        if (getChildCount() > 0) {
+            switch (action) {
+                case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: {
+                    if (!mIsClearAllButtonFullyRevealed && getCurrentPage() == getPageCount() - 1) {
+                        revealClearAllButton();
+                        return true;
+                    }
+                }
+                case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: {
+                    if (mIsClearAllButtonFullyRevealed) {
+                        setCurrentPage(getChildCount() - 1);
+                        return true;
+                    }
+                }
+                break;
+            }
+        }
+        return super.performAccessibilityAction(action, arguments);
+    }
+
+    @Override
     public void addChildrenForAccessibility(ArrayList<View> outChildren) {
+        outChildren.add(mClearAllButton);
         for (int i = getChildCount() - 1; i >= 0; --i) {
             outChildren.add(getChildAt(i));
         }
@@ -1295,6 +1326,13 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
     public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
         super.onInitializeAccessibilityNodeInfo(info);
 
+        if (getChildCount() > 0) {
+            info.addAction(mIsClearAllButtonFullyRevealed ?
+                    AccessibilityNodeInfo.ACTION_SCROLL_FORWARD :
+                    AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD);
+            info.setScrollable(true);
+        }
+
         final AccessibilityNodeInfo.CollectionInfo
                 collectionInfo = AccessibilityNodeInfo.CollectionInfo.obtain(
                 1, getChildCount(), false,
@@ -1306,11 +1344,15 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
     public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
         super.onInitializeAccessibilityEvent(event);
 
-        if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
-            final int visiblePageNumber = getChildCount() - getCurrentPage() - 1;
-            event.setFromIndex(visiblePageNumber);
-            event.setToIndex(visiblePageNumber);
-            event.setItemCount(getChildCount());
+        event.setScrollable(getPageCount() > 0);
+
+        if (!mIsClearAllButtonFullyRevealed
+                && event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) {
+            final int childCount = getChildCount();
+            final int[] visibleTasks = getVisibleChildrenRange();
+            event.setFromIndex(childCount - visibleTasks[1] - 1);
+            event.setToIndex(childCount - visibleTasks[0] - 1);
+            event.setItemCount(childCount);
         }
     }
 
@@ -1325,9 +1367,6 @@ public abstract class RecentsView<T extends BaseActivity> extends PagedView impl
         return true;
     }
 
-    public void addTaskAccessibilityActionsExtra(AccessibilityNodeInfo info) {
-    }
-
     public boolean performTaskAccessibilityActionExtra(int action) {
         return false;
     }