Merge "Add support for stretch overscroll to internal ViewPager" into sc-dev

1 files changed, 75 insertions, 9 deletions

diff --git a/core/java/com/android/internal/widget/ViewPager.java b/core/java/com/android/internal/widget/ViewPager.java
index 6f377b9b228a..93cde3ddb72d 100644
--- a/core/java/com/android/internal/widget/ViewPager.java
+++ b/core/java/com/android/internal/widget/ViewPager.java
@@ -353,8 +353,8 @@ public class ViewPager extends ViewGroup {
         mTouchSlop = configuration.getScaledPagingTouchSlop();
         mMinimumVelocity = (int) (MIN_FLING_VELOCITY * density);
         mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
-        mLeftEdge = new EdgeEffect(context);
-        mRightEdge = new EdgeEffect(context);
+        mLeftEdge = new EdgeEffect(context, attrs);
+        mRightEdge = new EdgeEffect(context, attrs);
 
         mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density);
         mCloseEnough = (int) (CLOSE_ENOUGH * density);
@@ -387,6 +387,28 @@ public class ViewPager extends ViewGroup {
     }
 
     /**
+     * Returns the {@link EdgeEffect#getType()} for the edge effects.
+     * @return the {@link EdgeEffect#getType()} for the edge effects.
+     * @attr ref android.R.styleable#EdgeEffect_edgeEffectType
+     */
+    @EdgeEffect.EdgeEffectType
+    public int getEdgeEffectType() {
+        // Both left and right edge have the same edge effect type
+        return mLeftEdge.getType();
+    }
+
+    /**
+     * Sets the {@link EdgeEffect#setType(int)} for the edge effects.
+     * @param type The edge effect type to use for the edge effects.
+     * @attr ref android.R.styleable#EdgeEffect_edgeEffectType
+     */
+    public void setEdgeEffectType(@EdgeEffect.EdgeEffectType int type) {
+        mLeftEdge.setType(type);
+        mRightEdge.setType(type);
+        invalidate();
+    }
+
+    /**
      * Set a PagerAdapter that will supply views for this pager as needed.
      *
      * @param adapter Adapter to use
@@ -1891,7 +1913,7 @@ public class ViewPager extends ViewGroup {
                 }
                 if (mIsBeingDragged) {
                     // Scroll to follow the motion event
-                    if (performDrag(x)) {
+                    if (performDrag(x, y)) {
                         postInvalidateOnAnimation();
                     }
                 }
@@ -1918,6 +1940,17 @@ public class ViewPager extends ViewGroup {
                     mIsBeingDragged = true;
                     requestParentDisallowInterceptTouchEvent(true);
                     setScrollState(SCROLL_STATE_DRAGGING);
+                } else if (mLeftEdge.getDistance() != 0
+                        || mRightEdge.getDistance() != 0) {
+                    // Caught the edge glow animation
+                    mIsBeingDragged = true;
+                    setScrollState(SCROLL_STATE_DRAGGING);
+                    if (mLeftEdge.getDistance() != 0) {
+                        mLeftEdge.onPullDistance(0f, 1 - mLastMotionY / getHeight());
+                    }
+                    if (mRightEdge.getDistance() != 0) {
+                        mRightEdge.onPullDistance(0f, mLastMotionY / getHeight());
+                    }
                 } else {
                     completeScroll(false);
                     mIsBeingDragged = false;
@@ -2009,7 +2042,7 @@ public class ViewPager extends ViewGroup {
                     // Scroll to follow the motion event
                     final int activePointerIndex = ev.findPointerIndex(mActivePointerId);
                     final float x = ev.getX(activePointerIndex);
-                    needsInvalidate |= performDrag(x);
+                    needsInvalidate |= performDrag(x, ev.getY(activePointerIndex));
                 }
                 break;
             case MotionEvent.ACTION_UP:
@@ -2080,12 +2113,43 @@ public class ViewPager extends ViewGroup {
         }
     }
 
-    private boolean performDrag(float x) {
+    /**
+     * If either of the horizontal edge glows are currently active, this consumes part or all of
+     * deltaX on the edge glow.
+     *
+     * @param deltaX The pointer motion, in pixels, in the horizontal direction, positive
+     *                         for moving down and negative for moving up.
+     * @param y The vertical position of the pointer.
+     * @return The amount of <code>deltaX</code> that has been consumed by the
+     * edge glow.
+     */
+    private float releaseHorizontalGlow(float deltaX, float y) {
+        // First allow releasing existing overscroll effect:
+        float consumed = 0;
+        float displacement = y / getHeight();
+        float pullDistance = (float) deltaX / getWidth();
+        if (mLeftEdge.getDistance() != 0) {
+            consumed = -mLeftEdge.onPullDistance(-pullDistance, 1 - displacement);
+        } else if (mRightEdge.getDistance() != 0) {
+            consumed = mRightEdge.onPullDistance(pullDistance, displacement);
+        }
+        return consumed * getWidth();
+    }
+
+    private boolean performDrag(float x, float y) {
         boolean needsInvalidate = false;
 
+        final float dX = mLastMotionX - x;
         final int width = getPaddedWidth();
-        final float deltaX = mLastMotionX - x;
         mLastMotionX = x;
+        final float releaseConsumed = releaseHorizontalGlow(dX, y);
+        final float deltaX = dX - releaseConsumed;
+        if (releaseConsumed != 0) {
+            needsInvalidate = true;
+        }
+        if (Math.abs(deltaX) < 0.0001f) { // ignore rounding errors from releaseHorizontalGlow()
+            return needsInvalidate;
+        }
 
         final EdgeEffect startEdge;
         final EdgeEffect endEdge;
@@ -2128,14 +2192,14 @@ public class ViewPager extends ViewGroup {
         if (scrollStart < startBound) {
             if (startAbsolute) {
                 final float over = startBound - scrollStart;
-                startEdge.onPull(Math.abs(over) / width);
+                startEdge.onPullDistance(over / width, 1 - y / getHeight());
                 needsInvalidate = true;
             }
             clampedScrollStart = startBound;
         } else if (scrollStart > endBound) {
             if (endAbsolute) {
                 final float over = scrollStart - endBound;
-                endEdge.onPull(Math.abs(over) / width);
+                endEdge.onPullDistance(over / width, y / getHeight());
                 needsInvalidate = true;
             }
             clampedScrollStart = endBound;
@@ -2228,7 +2292,9 @@ public class ViewPager extends ViewGroup {
      */
     private int determineTargetPage(int currentPage, float pageOffset, int velocity, int deltaX) {
         int targetPage;
-        if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) {
+        if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity
+                && mLeftEdge.getDistance() == 0 // don't fling while stretched
+                && mRightEdge.getDistance() == 0) {
             targetPage = currentPage - (velocity < 0 ? mLeftIncr : 0);
         } else {
             final float truncator = currentPage >= mCurItem ? 0.4f : 0.6f;