Invalidate for scrolling animations on the animation timer

Change View methods awakenScrollBars and scrollTo to post their
invalidation on the animation timer. Since these are often used in
computeScroll or similar to continue scrolling or flinging it should
not prevent other posted events from being processed before the frame
is actually drawn. (All changes in scroll position, etc. are
immediately reflected after the calls and do not need a draw to
present correct data about scroll position to apps.)

Don't accumulate floating point error while dragging
ScrollView/HorizontalScrollView.

Change-Id: I05b57d75f89a806488e46a8fb79b85d80f56d45d

1 files changed, 19 insertions, 19 deletions

diff --git a/core/java/android/widget/ScrollView.java b/core/java/android/widget/ScrollView.java
index e0e3e93..0f0dbae 100644
--- a/core/java/android/widget/ScrollView.java
+++ b/core/java/android/widget/ScrollView.java
@@ -73,7 +73,7 @@ public class ScrollView extends FrameLayout {
     /**
      * Position of the last motion event.
      */
-    private float mLastMotionY;
+    private int mLastMotionY;
 
     /**
      * True when the layout has changed but the traversal has not come through yet.
@@ -472,8 +472,8 @@ public class ScrollView extends FrameLayout {
                 }
 
                 final int pointerIndex = ev.findPointerIndex(activePointerId);
-                final float y = ev.getY(pointerIndex);
-                final int yDiff = (int) Math.abs(y - mLastMotionY);
+                final int y = (int) ev.getY(pointerIndex);
+                final int yDiff = Math.abs(y - mLastMotionY);
                 if (yDiff > mTouchSlop) {
                     mIsBeingDragged = true;
                     mLastMotionY = y;
@@ -487,7 +487,7 @@ public class ScrollView extends FrameLayout {
             }
 
             case MotionEvent.ACTION_DOWN: {
-                final float y = ev.getY();
+                final int y = (int) ev.getY();
                 if (!inChild((int) ev.getX(), (int) y)) {
                     mIsBeingDragged = false;
                     recycleVelocityTracker();
@@ -522,7 +522,7 @@ public class ScrollView extends FrameLayout {
                 mActivePointerId = INVALID_POINTER;
                 recycleVelocityTracker();
                 if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) {
-                    invalidate();
+                    postInvalidateOnAnimation();
                 }
                 break;
             case MotionEvent.ACTION_POINTER_UP:
@@ -564,7 +564,7 @@ public class ScrollView extends FrameLayout {
                 }
 
                 // Remember where the motion event started
-                mLastMotionY = ev.getY();
+                mLastMotionY = (int) ev.getY();
                 mActivePointerId = ev.getPointerId(0);
                 break;
             }
@@ -572,8 +572,8 @@ public class ScrollView extends FrameLayout {
                 if (mIsBeingDragged) {
                     // Scroll to follow the motion event
                     final int activePointerIndex = ev.findPointerIndex(mActivePointerId);
-                    final float y = ev.getY(activePointerIndex);
-                    final int deltaY = (int) (mLastMotionY - y);
+                    final int y = (int) ev.getY(activePointerIndex);
+                    final int deltaY = mLastMotionY - y;
                     mLastMotionY = y;
 
                     final int oldX = mScrollX;
@@ -605,7 +605,7 @@ public class ScrollView extends FrameLayout {
                         }
                         if (mEdgeGlowTop != null
                                 && (!mEdgeGlowTop.isFinished() || !mEdgeGlowBottom.isFinished())) {
-                            invalidate();
+                            postInvalidateOnAnimation();
                         }
                     }
                 }
@@ -622,7 +622,7 @@ public class ScrollView extends FrameLayout {
                         } else {
                             if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0,
                                     getScrollRange())) {
-                                invalidate();
+                                postInvalidateOnAnimation();
                             }
                         }
                     }
@@ -634,7 +634,7 @@ public class ScrollView extends FrameLayout {
             case MotionEvent.ACTION_CANCEL:
                 if (mIsBeingDragged && getChildCount() > 0) {
                     if (mScroller.springBack(mScrollX, mScrollY, 0, 0, 0, getScrollRange())) {
-                        invalidate();
+                        postInvalidateOnAnimation();
                     }
                     mActivePointerId = INVALID_POINTER;
                     endDrag();
@@ -642,13 +642,13 @@ public class ScrollView extends FrameLayout {
                 break;
             case MotionEvent.ACTION_POINTER_DOWN: {
                 final int index = ev.getActionIndex();
-                mLastMotionY = ev.getY(index);
+                mLastMotionY = (int) ev.getY(index);
                 mActivePointerId = ev.getPointerId(index);
                 break;
             }
             case MotionEvent.ACTION_POINTER_UP:
                 onSecondaryPointerUp(ev);
-                mLastMotionY = ev.getY(ev.findPointerIndex(mActivePointerId));
+                mLastMotionY = (int) ev.getY(ev.findPointerIndex(mActivePointerId));
                 break;
         }
         return true;
@@ -663,7 +663,7 @@ public class ScrollView extends FrameLayout {
             // active pointer and adjust accordingly.
             // TODO: Make this decision more intelligent.
             final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
-            mLastMotionY = ev.getY(newPointerIndex);
+            mLastMotionY = (int) ev.getY(newPointerIndex);
             mActivePointerId = ev.getPointerId(newPointerIndex);
             if (mVelocityTracker != null) {
                 mVelocityTracker.clear();
@@ -1047,7 +1047,7 @@ public class ScrollView extends FrameLayout {
             dy = Math.max(0, Math.min(scrollY + dy, maxY)) - scrollY;
 
             mScroller.startScroll(mScrollX, scrollY, 0, dy);
-            invalidate();
+            postInvalidateOnAnimation();
         } else {
             if (!mScroller.isFinished()) {
                 mScroller.abortAnimation();
@@ -1174,7 +1174,7 @@ public class ScrollView extends FrameLayout {
 
             if (!awakenScrollBars()) {
                 // Keep on drawing until the animation has finished.
-                invalidate();
+                postInvalidateOnAnimation();
             }
         } else {
             if (mFlingStrictSpan != null) {
@@ -1430,7 +1430,7 @@ public class ScrollView extends FrameLayout {
                 mFlingStrictSpan = StrictMode.enterCriticalSpan("ScrollView-fling");
             }
 
-            invalidate();
+            postInvalidateOnAnimation();
         }
     }
 
@@ -1495,7 +1495,7 @@ public class ScrollView extends FrameLayout {
                 canvas.translate(mPaddingLeft, Math.min(0, scrollY));
                 mEdgeGlowTop.setSize(width, getHeight());
                 if (mEdgeGlowTop.draw(canvas)) {
-                    invalidate();
+                    postInvalidateOnAnimation();
                 }
                 canvas.restoreToCount(restoreCount);
             }
@@ -1509,7 +1509,7 @@ public class ScrollView extends FrameLayout {
                 canvas.rotate(180, width, 0);
                 mEdgeGlowBottom.setSize(width, height);
                 if (mEdgeGlowBottom.draw(canvas)) {
-                    invalidate();
+                    postInvalidateOnAnimation();
                 }
                 canvas.restoreToCount(restoreCount);
             }