Tuning the TouchExplorer

1. Tuned the max angle between two moving fingers in touch
   exploration mode for a gesture to be considered a drag.
   The previous value was too aggressive and it was fairly
   easy for the user to get out of dragging state if she
   ingreases the distance between her fingers.

bug:5223787

2. Before clicking the explorer was sending hover enter and
   exit resulting in firing the corresponding accessibility
   events which leads to announcement of the content under
   the tap that triggered the click. However, the click is
   actually performed on the last touch explored location
   (if in the distance slop of course) instead of the actual
   tapping pointer location. Before fixing that the user was
   confused since he was hearing announcement of one content
   but actually was clicking on something else.

bug:5225721

Change-Id: I79fec704878f98c95f181bf8a9647e0bb1bd10ef

1 files changed, 17 insertions, 4 deletions

diff --git a/services/java/com/android/server/accessibility/TouchExplorer.java b/services/java/com/android/server/accessibility/TouchExplorer.java
index 496210c..eb399ad 100644
--- a/services/java/com/android/server/accessibility/TouchExplorer.java
+++ b/services/java/com/android/server/accessibility/TouchExplorer.java
@@ -84,7 +84,7 @@ public class TouchExplorer implements Explorer {
 
     // The minimum of the cosine between the vectors of two moving
     // pointers so they can be considered moving in the same direction.
-    private static final float MIN_ANGLE_COS = 0.866025404f; // cos(pi/6)
+    private static final float MAX_DRAGGING_ANGLE_COS = 0.525321989f; // cos(pi/4)
 
     // The delay for sending a hover enter event.
     private static final long DELAY_SEND_HOVER_ENTER = 200;
@@ -364,13 +364,13 @@ public class TouchExplorer implements Explorer {
                         }
 
                         mPerformLongPressDelayed.remove();
-                        mSendHoverDelayed.forceSendAndRemove();
-                        ensureHoverExitSent(event, pointerIdBits, policyFlags);
 
                         // If touch exploring announce the end of the gesture.
                         // Also do not click on the last explored location.
                         if (mTouchExploreGestureInProgress) {
                             mTouchExploreGestureInProgress = false;
+                            mSendHoverDelayed.forceSendAndRemove();
+                            ensureHoverExitSent(event, pointerIdBits, policyFlags);
                             mLastTouchExploreEvent = MotionEvent.obtain(event);
                             sendAccessibilityEvent(TYPE_TOUCH_EXPLORATION_GESTURE_END);
                             break;
@@ -384,6 +384,8 @@ public class TouchExplorer implements Explorer {
                             final long exploreTime = mLastTouchExploreEvent.getEventTime();
                             final long deltaTime = eventTime - exploreTime;
                             if (deltaTime > ACTIVATION_TIME_SLOP) {
+                                mSendHoverDelayed.forceSendAndRemove();
+                                ensureHoverExitSent(event, pointerIdBits, policyFlags);
                                 mLastTouchExploreEvent = MotionEvent.obtain(event);
                                 break;
                             }
@@ -396,14 +398,25 @@ public class TouchExplorer implements Explorer {
                                     - event.getY(pointerIndex);
                             final float deltaMove = (float) Math.hypot(deltaX, deltaY);
                             if (deltaMove > mTouchExplorationTapSlop) {
+                                mSendHoverDelayed.forceSendAndRemove();
+                                ensureHoverExitSent(event, pointerIdBits, policyFlags);
                                 mLastTouchExploreEvent = MotionEvent.obtain(event);
                                 break;
                             }
 
+                            // This is a tap so do not send hover events since
+                            // this events will result in firing the corresponding
+                            // accessibility events confusing the user about what
+                            // is actually clicked.
+                            mSendHoverDelayed.remove();
+                            ensureHoverExitSent(event, pointerIdBits, policyFlags);
+
                             // All preconditions are met, so click the last explored location.
                             sendActionDownAndUp(mLastTouchExploreEvent, policyFlags);
                             mLastTouchExploreEvent = null;
                         } else {
+                            mSendHoverDelayed.forceSendAndRemove();
+                            ensureHoverExitSent(event, pointerIdBits, policyFlags);
                             mLastTouchExploreEvent = MotionEvent.obtain(event);
                         }
                     } break;
@@ -782,7 +795,7 @@ public class TouchExplorer implements Explorer {
         final float angleCos =
             firstXNormalized * secondXNormalized + firstYNormalized * secondYNormalized;
 
-        if (angleCos < MIN_ANGLE_COS) {
+        if (angleCos < MAX_DRAGGING_ANGLE_COS) {
             return false;
         }