Support fling back in scrolling containers (28b3b51c) · Commits · e / os / android_frameworks_base

core/java/android/widget/AbsListView.java

+85 −3

Original line number	Diff line number	Diff line
		@@ -241,6 +241,14 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		*/
		public static final int CHOICE_MODE_MULTIPLE_MODAL = 3;

		/**
		* When flinging the stretch towards scrolling content, it should destretch quicker than the
		* fling would normally do. The visual effect of flinging the stretch looks strange as little
		* appears to happen at first and then when the stretch disappears, the content starts
		* scrolling quickly.
		*/
		private static final float FLING_DESTRETCH_FACTOR = 4f;

		/**
		* The thread that created this view.
		*/
		@@ -4216,9 +4224,23 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		// fling further.
		boolean flingVelocity = Math.abs(initialVelocity) > mMinimumVelocity;
		if (flingVelocity && !mEdgeGlowTop.isFinished()) {
		if (shouldAbsorb(mEdgeGlowTop, initialVelocity)) {
		mEdgeGlowTop.onAbsorb(initialVelocity);
		} else {
		if (mFlingRunnable == null) {
		mFlingRunnable = new FlingRunnable();
		}
		mFlingRunnable.start(-initialVelocity);
		}
		} else if (flingVelocity && !mEdgeGlowBottom.isFinished()) {
		if (shouldAbsorb(mEdgeGlowBottom, -initialVelocity)) {
		mEdgeGlowBottom.onAbsorb(-initialVelocity);
		} else {
		if (mFlingRunnable == null) {
		mFlingRunnable = new FlingRunnable();
		}
		mFlingRunnable.start(-initialVelocity);
		}
		} else if (flingVelocity
		&& !((mFirstPosition == 0
		&& firstChildTop == contentTop - mOverscrollDistance)
		@@ -4301,6 +4323,60 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		}
		}

		/**
		* Returns true if edgeEffect should call onAbsorb() with veclocity or false if it should
		* animate with a fling. It will animate with a fling if the velocity will remove the
		* EdgeEffect through its normal operation.
		*
		* @param edgeEffect The EdgeEffect that might absorb the velocity.
		* @param velocity The velocity of the fling motion
		* @return true if the velocity should be absorbed or false if it should be flung.
		*/
		private boolean shouldAbsorb(EdgeEffect edgeEffect, int velocity) {
		if (velocity > 0) {
		return true;
		}
		float distance = edgeEffect.getDistance() * getHeight();

		// This is flinging without the spring, so let's see if it will fling past the overscroll
		if (mFlingRunnable == null) {
		mFlingRunnable = new FlingRunnable();
		}
		float flingDistance = mFlingRunnable.getSplineFlingDistance(-velocity);

		return flingDistance < distance;
		}

		/**
		* Used by consumeFlingInHorizontalStretch() and consumeFlinInVerticalStretch() for
		* consuming deltas from EdgeEffects
		* @param unconsumed The unconsumed delta that the EdgeEffets may consume
		* @return The unconsumed delta after the EdgeEffects have had an opportunity to consume.
		*/
		private int consumeFlingInStretch(int unconsumed) {
		if (unconsumed < 0 && mEdgeGlowTop != null && mEdgeGlowTop.getDistance() != 0f) {
		int size = getHeight();
		float deltaDistance = unconsumed * FLING_DESTRETCH_FACTOR / size;
		int consumed = Math.round(size / FLING_DESTRETCH_FACTOR
		* mEdgeGlowTop.onPullDistance(deltaDistance, 0.5f));
		if (consumed != unconsumed) {
		mEdgeGlowTop.finish();
		}
		return unconsumed - consumed;
		}
		if (unconsumed > 0 && mEdgeGlowBottom != null && mEdgeGlowBottom.getDistance() != 0f) {
		int size = getHeight();
		float deltaDistance = -unconsumed * FLING_DESTRETCH_FACTOR / size;
		int consumed = Math.round(-size / FLING_DESTRETCH_FACTOR
		* mEdgeGlowBottom.onPullDistance(deltaDistance, 0.5f));
		if (consumed != unconsumed) {
		mEdgeGlowBottom.finish();
		}
		return unconsumed - consumed;
		}
		return unconsumed;
		}

		private boolean shouldDisplayEdgeEffects() {
		return getOverScrollMode() != OVER_SCROLL_NEVER;
		}
		@@ -4783,6 +4859,10 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		mScroller = new OverScroller(getContext());
		}

		float getSplineFlingDistance(int velocity) {
		return (float) mScroller.getSplineFlingDistance(velocity);
		}

		// Use AbsListView#fling(int) instead
		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
		void start(int initialVelocity) {
		@@ -4905,6 +4985,8 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te
		}

		if (mItemCount == 0 \|\| getChildCount() == 0) {
		mEdgeGlowBottom.onRelease();
		mEdgeGlowTop.onRelease();
		endFling();
		return;
		}
		@@ -4915,7 +4997,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te

		// Flip sign to convert finger direction to list items direction
		// (e.g. finger moving down means list is moving towards the top)
		int delta = mLastFlingY - y;
		int delta = consumeFlingInStretch(mLastFlingY - y);

		// Pretend that each frame of a fling scroll is a touch scroll
		if (delta > 0) {

core/java/android/widget/HorizontalScrollView.java

+77 −5

Original line number	Diff line number	Diff line
		@@ -77,6 +77,14 @@ public class HorizontalScrollView extends FrameLayout {

		private static final String TAG = "HorizontalScrollView";

		/**
		* When flinging the stretch towards scrolling content, it should destretch quicker than the
		* fling would normally do. The visual effect of flinging the stretch looks strange as little
		* appears to happen at first and then when the stretch disappears, the content starts
		* scrolling quickly.
		*/
		private static final float FLING_DESTRETCH_FACTOR = 4f;

		private long mLastScroll;

		private final Rect mTempRect = new Rect();
		@@ -1456,18 +1464,19 @@ public class HorizontalScrollView extends FrameLayout {
		int oldY = mScrollY;
		int x = mScroller.getCurrX();
		int y = mScroller.getCurrY();
		int deltaX = consumeFlingInStretch(x - oldX);

		if (oldX != x \|\| oldY != y) {
		if (deltaX != 0 \|\| oldY != y) {
		final int range = getScrollRange();
		final int overscrollMode = getOverScrollMode();
		final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS \|\|
		(overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0);

		overScrollBy(x - oldX, y - oldY, oldX, oldY, range, 0,
		overScrollBy(deltaX, y - oldY, oldX, oldY, range, 0,
		mOverflingDistance, 0, false);
		onScrollChanged(mScrollX, mScrollY, oldX, oldY);

		if (canOverscroll) {
		if (canOverscroll && deltaX != 0) {
		if (x < 0 && oldX >= 0) {
		mEdgeGlowLeft.onAbsorb((int) mScroller.getCurrVelocity());
		} else if (x > range && oldX <= range) {
		@@ -1482,6 +1491,36 @@ public class HorizontalScrollView extends FrameLayout {
		}
		}

		/**
		* Used by consumeFlingInHorizontalStretch() and consumeFlinInVerticalStretch() for
		* consuming deltas from EdgeEffects
		* @param unconsumed The unconsumed delta that the EdgeEffets may consume
		* @return The unconsumed delta after the EdgeEffects have had an opportunity to consume.
		*/
		private int consumeFlingInStretch(int unconsumed) {
		if (unconsumed > 0 && mEdgeGlowLeft != null && mEdgeGlowLeft.getDistance() != 0f) {
		int size = getWidth();
		float deltaDistance = -unconsumed * FLING_DESTRETCH_FACTOR / size;
		int consumed = Math.round(-size / FLING_DESTRETCH_FACTOR
		* mEdgeGlowLeft.onPullDistance(deltaDistance, 0.5f));
		if (consumed != unconsumed) {
		mEdgeGlowLeft.finish();
		}
		return unconsumed - consumed;
		}
		if (unconsumed < 0 && mEdgeGlowRight != null && mEdgeGlowRight.getDistance() != 0f) {
		int size = getWidth();
		float deltaDistance = unconsumed * FLING_DESTRETCH_FACTOR / size;
		int consumed = Math.round(size / FLING_DESTRETCH_FACTOR
		* mEdgeGlowRight.onPullDistance(deltaDistance, 0.5f));
		if (consumed != unconsumed) {
		mEdgeGlowRight.finish();
		}
		return unconsumed - consumed;
		}
		return unconsumed;
		}

		/**
		* Scrolls the view to the given child.
		*
		@@ -1746,11 +1785,23 @@ public class HorizontalScrollView extends FrameLayout {

		int maxScroll = Math.max(0, right - width);

		boolean shouldFling = false;
		if (mScrollX == 0 && !mEdgeGlowLeft.isFinished()) {
		if (shouldAbsorb(mEdgeGlowLeft, -velocityX)) {
		mEdgeGlowLeft.onAbsorb(-velocityX);
		} else {
		shouldFling = true;
		}
		} else if (mScrollX == maxScroll && !mEdgeGlowRight.isFinished()) {
		if (shouldAbsorb(mEdgeGlowRight, velocityX)) {
		mEdgeGlowRight.onAbsorb(velocityX);
		} else {
		shouldFling = true;
		}
		} else {
		shouldFling = true;
		}
		if (shouldFling) {
		mScroller.fling(mScrollX, mScrollY, velocityX, 0, 0,
		maxScroll, 0, 0, width / 2, 0);

		@@ -1773,6 +1824,27 @@ public class HorizontalScrollView extends FrameLayout {
		}
		}

		/**
		* Returns true if edgeEffect should call onAbsorb() with veclocity or false if it should
		* animate with a fling. It will animate with a fling if the velocity will remove the
		* EdgeEffect through its normal operation.
		*
		* @param edgeEffect The EdgeEffect that might absorb the velocity.
		* @param velocity The velocity of the fling motion
		* @return true if the velocity should be absorbed or false if it should be flung.
		*/
		private boolean shouldAbsorb(EdgeEffect edgeEffect, int velocity) {
		if (velocity > 0) {
		return true;
		}
		float distance = edgeEffect.getDistance() * getWidth();

		// This is flinging without the spring, so let's see if it will fling past the overscroll
		float flingDistance = (float) mScroller.getSplineFlingDistance(-velocity);

		return flingDistance < distance;
		}

		/**
		* {@inheritDoc}
		*

core/java/android/widget/OverScroller.java

+4 −0

Original line number	Diff line number	Diff line
		@@ -527,6 +527,10 @@ public class OverScroller {
		Math.signum(yvel) == Math.signum(dy);
		}

		double getSplineFlingDistance(int velocity) {
		return mScrollerY.getSplineFlingDistance(velocity);
		}

		static class SplineOverScroller {
		// Initial position
		private int mStart;

core/java/android/widget/ScrollView.java

+73 −5

Original line number	Diff line number	Diff line
		@@ -85,6 +85,14 @@ public class ScrollView extends FrameLayout {

		private static final String TAG = "ScrollView";

		/**
		* When flinging the stretch towards scrolling content, it should destretch quicker than the
		* fling would normally do. The visual effect of flinging the stretch looks strange as little
		* appears to happen at first and then when the stretch disappears, the content starts
		* scrolling quickly.
		*/
		private static final float FLING_DESTRETCH_FACTOR = 4f;

		@UnsupportedAppUsage
		private long mLastScroll;

		@@ -1488,18 +1496,19 @@ public class ScrollView extends FrameLayout {
		int oldY = mScrollY;
		int x = mScroller.getCurrX();
		int y = mScroller.getCurrY();
		int deltaY = consumeFlingInStretch(y - oldY);

		if (oldX != x \|\| oldY != y) {
		if (oldX != x \|\| deltaY != 0) {
		final int range = getScrollRange();
		final int overscrollMode = getOverScrollMode();
		final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS \|\|
		(overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS && range > 0);

		overScrollBy(x - oldX, y - oldY, oldX, oldY, 0, range,
		overScrollBy(x - oldX, deltaY, oldX, oldY, 0, range,
		0, mOverflingDistance, false);
		onScrollChanged(mScrollX, mScrollY, oldX, oldY);

		if (canOverscroll) {
		if (canOverscroll && deltaY != 0) {
		if (y < 0 && oldY >= 0) {
		mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity());
		} else if (y > range && oldY <= range) {
		@@ -1520,6 +1529,36 @@ public class ScrollView extends FrameLayout {
		}
		}

		/**
		* Used by consumeFlingInHorizontalStretch() and consumeFlinInVerticalStretch() for
		* consuming deltas from EdgeEffects
		* @param unconsumed The unconsumed delta that the EdgeEffets may consume
		* @return The unconsumed delta after the EdgeEffects have had an opportunity to consume.
		*/
		private int consumeFlingInStretch(int unconsumed) {
		if (unconsumed > 0 && mEdgeGlowTop != null && mEdgeGlowTop.getDistance() != 0f) {
		int size = getHeight();
		float deltaDistance = -unconsumed * FLING_DESTRETCH_FACTOR / size;
		int consumed = Math.round(-size / FLING_DESTRETCH_FACTOR
		* mEdgeGlowTop.onPullDistance(deltaDistance, 0.5f));
		if (consumed != unconsumed) {
		mEdgeGlowTop.finish();
		}
		return unconsumed - consumed;
		}
		if (unconsumed < 0 && mEdgeGlowBottom != null && mEdgeGlowBottom.getDistance() != 0f) {
		int size = getHeight();
		float deltaDistance = unconsumed * FLING_DESTRETCH_FACTOR / size;
		int consumed = Math.round(size / FLING_DESTRETCH_FACTOR
		* mEdgeGlowBottom.onPullDistance(deltaDistance, 0.5f));
		if (consumed != unconsumed) {
		mEdgeGlowBottom.finish();
		}
		return unconsumed - consumed;
		}
		return unconsumed;
		}

		/**
		* Scrolls the view to the given child.
		*
		@@ -1803,14 +1842,43 @@ public class ScrollView extends FrameLayout {
		fling(velocityY);
		} else if (!consumed) {
		if (!mEdgeGlowTop.isFinished()) {
		if (shouldAbsorb(mEdgeGlowTop, -velocityY)) {
		mEdgeGlowTop.onAbsorb(-velocityY);
		} else {
		fling(velocityY);
		}
		} else if (!mEdgeGlowBottom.isFinished()) {
		if (shouldAbsorb(mEdgeGlowBottom, velocityY)) {
		mEdgeGlowBottom.onAbsorb(velocityY);
		} else {
		fling(velocityY);
		}
		}
		}
		}
		}

		/**
		* Returns true if edgeEffect should call onAbsorb() with veclocity or false if it should
		* animate with a fling. It will animate with a fling if the velocity will remove the
		* EdgeEffect through its normal operation.
		*
		* @param edgeEffect The EdgeEffect that might absorb the velocity.
		* @param velocity The velocity of the fling motion
		* @return true if the velocity should be absorbed or false if it should be flung.
		*/
		private boolean shouldAbsorb(EdgeEffect edgeEffect, int velocity) {
		if (velocity > 0) {
		return true;
		}
		float distance = edgeEffect.getDistance() * getHeight();

		// This is flinging without the spring, so let's see if it will fling past the overscroll
		float flingDistance = (float) mScroller.getSplineFlingDistance(-velocity);

		return flingDistance < distance;
		}

		@UnsupportedAppUsage
		private void endDrag() {
		mIsBeingDragged = false;