Fix broken activation of the selected view in accessibility mode.

We were using an approximation to determine where to send a pair of down
and up events to click on the view that has accessibility focus. We were
doing reverse computation to figuring out which portion of the view is
not covered by interactive views and get a point in this region. However,
determining whether a view is interactive is not feasible in general since
for example may override onTouchEvent. This results in views not being
activated or which is worse wrong views being activated.

This change swithes to a new approach to activate views in accessibility
mode which is guaranteed to always work except the very rare case of a
view that overrides dispatchTouchEvent (which developers shouldn't be
doing). The new approach is to flag the down and up events pair sent
by the touch explorer as targeting the accessibility focused view. Such
events are dispatched such that views predecessors of the accessibility
focus do not handle them guaranteeing that these events reach the accessibiliy
focused view. Once the accessibiliy focused view gets such an event it clears
the flag and the event is dispatched following the normal event dispatch
semantics.

The new approach is semantically equivalent to requesting the view to perform
a click accessiblitiy action but is more generic as it is not affected by
views not implementing click action support correctly.

bug:18986806
bug:18889611

Change-Id: Id4b7b886c9fd34f7eb11e606636d8e3bab122869

1 files changed, 31 insertions, 0 deletions

diff --git a/core/java/android/view/MotionEvent.java b/core/java/android/view/MotionEvent.java
index 1c5c41c74905..5e45c8fe10dd 100644
--- a/core/java/android/view/MotionEvent.java
+++ b/core/java/android/view/MotionEvent.java
@@ -402,6 +402,23 @@ public final class MotionEvent extends InputEvent implements Parcelable {
     public static final int FLAG_TAINTED = 0x80000000;
 
     /**
+     * Private flag indicating that this event was synthesized by the system and
+     * should be delivered to the accessibility focused view first. When being
+     * dispatched such an event is not handled by predecessors of the accessibility
+     * focused view and after the event reaches that view the flag is cleared and
+     * normal event dispatch is performed. This ensures that the platform can click
+     * on any view that has accessibility focus which is semantically equivalent to
+     * asking the view to perform a click accessibility action but more generic as
+     * views not implementing click action correctly can still be activated.
+     *
+     * @hide
+     * @see #isTargetAccessibilityFocus()
+     * @see #setTargetAccessibilityFocus(boolean)
+     */
+    public static final int FLAG_TARGET_ACCESSIBILITY_FOCUS = 0x40000000;
+
+
+    /**
      * Flag indicating the motion event intersected the top edge of the screen.
      */
     public static final int EDGE_TOP = 0x00000001;
@@ -1766,6 +1783,20 @@ public final class MotionEvent extends InputEvent implements Parcelable {
         nativeSetFlags(mNativePtr, tainted ? flags | FLAG_TAINTED : flags & ~FLAG_TAINTED);
     }
 
+    /** @hide */
+    public final boolean isTargetAccessibilityFocus() {
+        final int flags = getFlags();
+        return (flags & FLAG_TARGET_ACCESSIBILITY_FOCUS) != 0;
+    }
+
+    /** @hide */
+    public final void setTargetAccessibilityFocus(boolean targetsFocus) {
+        final int flags = getFlags();
+        nativeSetFlags(mNativePtr, targetsFocus
+                ? flags | FLAG_TARGET_ACCESSIBILITY_FOCUS
+                : flags & ~FLAG_TARGET_ACCESSIBILITY_FOCUS);
+    }
+
     /**
      * Returns the time (in ms) when the user originally pressed down to start
      * a stream of position events.