Increases the falsing threshold when for the keyguard affordances

The minimum amount has been increased by 20dp and in addition the
Motion is cancelled whenever a POINTER_DOWN occurs, which should
help a lot with falsing.

Bug: 18298401
Change-Id: I04b1f30fd2555c08209224f4e84c610ecd7a33f1
(cherry picked from commit 1dc406505cdcbbf98ece4f15a2f98f621e24abdb)
diff --git a/packages/SystemUI/res/values/dimens.xml b/packages/SystemUI/res/values/dimens.xml
index fabdf29..fcdc015 100644
--- a/packages/SystemUI/res/values/dimens.xml
+++ b/packages/SystemUI/res/values/dimens.xml
@@ -320,7 +320,7 @@
     <dimen name="heads_up_window_height">250dp</dimen>
 
     <!-- The minimum amount the user needs to swipe to go to the camera / phone. -->
-    <dimen name="keyguard_min_swipe_amount">90dp</dimen>
+    <dimen name="keyguard_min_swipe_amount">110dp</dimen>
 
     <!-- The minimum background radius when swiping to a side for the camera / phone affordances. -->
     <dimen name="keyguard_affordance_min_background_radius">30dp</dimen>
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardAffordanceHelper.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardAffordanceHelper.java
index 6653254..f1dcffb 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardAffordanceHelper.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/KeyguardAffordanceHelper.java
@@ -46,7 +46,6 @@
 
     private FlingAnimationUtils mFlingAnimationUtils;
     private Callback mCallback;
-    private int mTrackingPointer;
     private VelocityTracker mVelocityTracker;
     private boolean mSwipingInProgress;
     private float mInitialTouchX;
@@ -65,6 +64,7 @@
     private Animator mSwipeAnimator;
     private int mMinBackgroundRadius;
     private boolean mMotionPerformedByUser;
+    private boolean mMotionCancelled;
     private AnimatorListenerAdapter mFlingEndListener = new AnimatorListenerAdapter() {
         @Override
         public void onAnimationEnd(Animator animation) {
@@ -117,13 +117,11 @@
     }
 
     public boolean onTouchEvent(MotionEvent event) {
-        int pointerIndex = event.findPointerIndex(mTrackingPointer);
-        if (pointerIndex < 0) {
-            pointerIndex = 0;
-            mTrackingPointer = event.getPointerId(pointerIndex);
+        if (mMotionCancelled && event.getActionMasked() != MotionEvent.ACTION_DOWN) {
+            return false;
         }
-        final float y = event.getY(pointerIndex);
-        final float x = event.getX(pointerIndex);
+        final float y = event.getY();
+        final float x = event.getX();
 
         boolean isUp = false;
         switch (event.getActionMasked()) {
@@ -137,22 +135,12 @@
                 initVelocityTracker();
                 trackMovement(event);
                 mMotionPerformedByUser = false;
+                mMotionCancelled = false;
                 break;
-
-            case MotionEvent.ACTION_POINTER_UP:
-                final int upPointer = event.getPointerId(event.getActionIndex());
-                if (mTrackingPointer == upPointer) {
-                    // gesture is ongoing, find a new pointer to track
-                    final int newIndex = event.getPointerId(0) != upPointer ? 0 : 1;
-                    final float newY = event.getY(newIndex);
-                    final float newX = event.getX(newIndex);
-                    mTrackingPointer = event.getPointerId(newIndex);
-                    mInitialTouchY = newY;
-                    mInitialTouchX = newX;
-                    mTranslationOnDown = mTranslation;
-                }
+            case MotionEvent.ACTION_POINTER_DOWN:
+                mMotionCancelled = true;
+                endMotion(event, true /* forceSnapBack */);
                 break;
-
             case MotionEvent.ACTION_MOVE:
                 final float w = x - mInitialTouchX;
                 trackMovement(event);
@@ -174,20 +162,23 @@
             case MotionEvent.ACTION_UP:
                 isUp = true;
             case MotionEvent.ACTION_CANCEL:
-                mTrackingPointer = -1;
                 trackMovement(event);
-                if (mSwipingInProgress) {
-                    flingWithCurrentVelocity(!isUp);
-                }
-                if (mVelocityTracker != null) {
-                    mVelocityTracker.recycle();
-                    mVelocityTracker = null;
-                }
+                endMotion(event, !isUp);
                 break;
         }
         return true;
     }
 
+    private void endMotion(MotionEvent event, boolean forceSnapBack) {
+        if (mSwipingInProgress) {
+            flingWithCurrentVelocity(forceSnapBack);
+        }
+        if (mVelocityTracker != null) {
+            mVelocityTracker.recycle();
+            mVelocityTracker = null;
+        }
+    }
+
     private void setSwipingInProgress(boolean inProgress) {
         mSwipingInProgress = inProgress;
         if (inProgress) {