Better handling of multiple touch events in GlowPadView

This fixes a bug where a secondary touch event from the edge of the screen
would cause GlowPadView to choose the wrong target.  The issue is resolved
by keeping track of pointer ids and only allowing the one that initiated
the gesture to complete it.

Fixes bug 7133500

Change-Id: If296b60af2421bfa1a9a082e608ba77b2392a218

Author: Jim Miller

core/java/com/android/internal/widget/multiwaveview/GlowPadView.java

@@ -197,6 +197,7 @@ public void onAnimationEnd(Animator animator) {
     private Tweener mBackgroundAnimator;
     private PointCloud mPointCloud;
     private float mInnerRadius;
+    private int mPointerId;
 
     public GlowPadView(Context context) {
         this(context, null);
@@ -737,9 +738,10 @@ private void startBackgroundAnimation(int duration, float alpha) {
 
     @Override
     public boolean onTouchEvent(MotionEvent event) {
-        final int action = event.getAction();
+        final int action = event.getActionMasked();
         boolean handled = false;
         switch (action) {
+            case MotionEvent.ACTION_POINTER_DOWN:
             case MotionEvent.ACTION_DOWN:
                 if (DEBUG) Log.v(TAG, "*** DOWN ***");
                 handleDown(event);
@@ -753,6 +755,7 @@ public boolean onTouchEvent(MotionEvent event) {
                 handled = true;
                 break;
 
+            case MotionEvent.ACTION_POINTER_UP:
             case MotionEvent.ACTION_UP:
                 if (DEBUG) Log.v(TAG, "*** UP ***");
                 handleMove(event);
@@ -766,6 +769,7 @@ public boolean onTouchEvent(MotionEvent event) {
                 handleCancel(event);
                 handled = true;
                 break;
+
         }
         invalidate();
         return handled ? true : super.onTouchEvent(event);
@@ -777,19 +781,24 @@ private void updateGlowPosition(float x, float y) {
     }
 
     private void handleDown(MotionEvent event) {
-        float eventX = event.getX();
-        float eventY = event.getY();
+        int actionIndex = event.getActionIndex();
+        float eventX = event.getX(actionIndex);
+        float eventY = event.getY(actionIndex);
         switchToState(STATE_START, eventX, eventY);
         if (!trySwitchToFirstTouchState(eventX, eventY)) {
             mDragging = false;
         } else {
+            mPointerId = event.getPointerId(actionIndex);
             updateGlowPosition(eventX, eventY);
         }
     }
 
     private void handleUp(MotionEvent event) {
         if (DEBUG && mDragging) Log.v(TAG, "** Handle RELEASE");
-        switchToState(STATE_FINISH, event.getX(), event.getY());
+        int actionIndex = event.getActionIndex();
+        if (event.getPointerId(actionIndex) == mPointerId) {
+            switchToState(STATE_FINISH, event.getX(actionIndex), event.getY(actionIndex));
+        }
     }
 
     private void handleCancel(MotionEvent event) {
@@ -802,7 +811,9 @@ private void handleCancel(MotionEvent event) {
 
         // mActiveTarget = -1; // Drop the active target if canceled.
 
-        switchToState(STATE_FINISH, event.getX(), event.getY());
+        int actionIndex = event.findPointerIndex(mPointerId);
+        actionIndex = actionIndex == -1 ? 0 : actionIndex;
+        switchToState(STATE_FINISH, event.getX(actionIndex), event.getY(actionIndex));
     }
 
     private void handleMove(MotionEvent event) {
@@ -812,9 +823,17 @@ private void handleMove(MotionEvent event) {
         int ntargets = targets.size();
         float x = 0.0f;
         float y = 0.0f;
+        int actionIndex = event.findPointerIndex(mPointerId);
+
+        if (actionIndex == -1) {
+            return;  // no data for this pointer
+        }
+
         for (int k = 0; k < historySize + 1; k++) {
-            float eventX = k < historySize ? event.getHistoricalX(k) : event.getX();
-            float eventY = k < historySize ? event.getHistoricalY(k) : event.getY();
+            float eventX = k < historySize ? event.getHistoricalX(actionIndex, k)
+                    : event.getX(actionIndex);
+            float eventY = k < historySize ? event.getHistoricalY(actionIndex, k)
+                    : event.getY(actionIndex);
             // tx and ty are relative to wave center
             float tx = eventX - mWaveCenterX;
             float ty = eventY - mWaveCenterY;