commit 2c430b34cbab3d156c93d90b457b70e3a869ec0a
author Vadim Tryshev <vadimt@google.com> Wed Apr 04 14:45:21 2018 -0700
committer Vadim Tryshev <vadimt@google.com> Thu Apr 05 10:53:08 2018 -0700
tree 939a0921d8900671a3a3aa5c1033a90dcc1a9340
parent ac6a6b6bf7e703bb5d40953c92c611321de9880b

Avoid duplicate accessibility announcement upon switching to -1st page

Since -1st window already has accessible description, no need to
announce "Page X of Y" for it.

Bug: 74210311
Test: Manual
Change-Id: I5cbfd763778b5f7049be732a750df4501b5419e0

src/com/android/launcher3/PagedView.java

diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index 79993c1..15bf76d 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -424,6 +424,13 @@
         return computeScrollHelper(true);
     }
 
+    protected void announcePageForAccessibility() {
+        if (isAccessibilityEnabled(getContext())) {
+            // Notify the user when the page changes
+            announceForAccessibility(getCurrentPageDescription());
+        }
+    }
+
     protected boolean computeScrollHelper(boolean shouldInvalidate) {
         if (mScroller.computeScrollOffset()) {
             // Don't bother scrolling if the page does not need to be moved
@@ -452,9 +459,8 @@
                 pageEndTransition();
             }
 
-            if (isAccessibilityEnabled(getContext())) {
-                // Notify the user when the page changes
-                announceForAccessibility(getCurrentPageDescription());
+            if (canAnnouncePageDescription()) {
+                announcePageForAccessibility();
             }
         }
         return false;
@@ -1535,6 +1541,10 @@
         return getCurrentPageDescription();
     }
 
+    protected boolean canAnnouncePageDescription() {
+        return true;
+    }
+
     protected String getCurrentPageDescription() {
         return getContext().getString(R.string.default_scroll_format,
                 getNextPage() + 1, getChildCount());

src/com/android/launcher3/Workspace.java

diff --git a/src/com/android/launcher3/Workspace.java b/src/com/android/launcher3/Workspace.java
index 34ae8ea..a39d273 100644
--- a/src/com/android/launcher3/Workspace.java
+++ b/src/com/android/launcher3/Workspace.java
@@ -1143,30 +1143,37 @@
      * The overlay scroll is being controlled locally, just update our overlay effect
      */
     public void onOverlayScrollChanged(float scroll) {
-
         if (Float.compare(scroll, 1f) == 0) {
             if (!mOverlayShown) {
                 mLauncher.getUserEventDispatcher().logActionOnContainer(Action.Touch.SWIPE,
                         Action.Direction.LEFT, ContainerType.WORKSPACE, 0);
             }
             mOverlayShown = true;
+            // Not announcing the overlay page for accessibility since it announces itself.
         } else if (Float.compare(scroll, 0f) == 0) {
             if (mOverlayShown) {
                 mLauncher.getUserEventDispatcher().logActionOnContainer(Action.Touch.SWIPE,
                         Action.Direction.RIGHT, ContainerType.WORKSPACE, -1);
+            } else if (Float.compare(mOverlayTranslation, 0f) != 0) {
+                // When arriving to 0 overscroll from non-zero overscroll, announce page for
+                // accessibility since default announcements were disabled while in overscroll
+                // state.
+                // Not doing this if mOverlayShown because in that case the accessibility service
+                // will announce the launcher window description upon regaining focus after
+                // switching from the overlay screen.
+                announcePageForAccessibility();
             }
             mOverlayShown = false;
             tryRunOverlayCallback();
         }
+
         float offset = 0f;
-        float slip = 0f;
 
         scroll = Math.max(scroll - offset, 0);
         scroll = Math.min(1, scroll / (1 - offset));
 
         float alpha = 1 - Interpolators.DEACCEL_3.getInterpolation(scroll);
         float transX = mLauncher.getDragLayer().getMeasuredWidth() * scroll;
-        transX *= 1 - slip;
 
         if (mIsRtl) {
             transX = -transX;
@@ -3345,6 +3352,13 @@
     }
 
     @Override
+    protected boolean canAnnouncePageDescription() {
+        // Disable announcements while overscrolling potentially to overlay screen because if we end
+        // up on the overlay screen, it will take care of announcing itself.
+        return Float.compare(mOverlayTranslation, 0f) == 0;
+    }
+
+    @Override
     protected String getCurrentPageDescription() {
         int page = (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
         return getPageDescription(page);