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Commit 744beffb authored by Adam Powell's avatar Adam Powell
Browse files

Track persistent nested Y offset for fling velocity 

Track the nested offsets applied persistently in AbsListView and
ScrollView. This allows accurate velocity to be reported to nested
fling/pre-fling.

Bug 17548219

Change-Id: I66199c534aca7fb81746eff6d04c931e4c4e48da
parent c90b5ebb

core/java/android/widget/AbsListView.java

+15 −2
Original line number Diff line number Diff line
@@ -611,6 +611,12 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
    private final int[] mScrollOffset = new int[2];

    private final int[] mScrollConsumed = new int[2];



    // Used for offsetting MotionEvents that we feed to the VelocityTracker.

    // In the future it would be nice to be able to give this to the VelocityTracker

    // directly, or alternatively put a VT into absolute-positioning mode that only

    // reads the raw screen-coordinate x/y values.

    private int mNestedYOffset = 0;



    // True when the popup should be hidden because of a call to

    // dispatchDisplayHint()

    private boolean mPopupHidden;
@@ -3330,6 +3336,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            scrollConsumedCorrection = mScrollConsumed[1];

            if (vtev != null) {

                vtev.offsetLocation(0, mScrollOffset[1]);

                mNestedYOffset += mScrollOffset[1];

            }

        }

        final int deltaY = rawDeltaY;
@@ -3399,6 +3406,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                            lastYCorrection -= mScrollOffset[1];

                            if (vtev != null) {

                                vtev.offsetLocation(0, mScrollOffset[1]);

                                mNestedYOffset += mScrollOffset[1];

                            }

                        } else {

                            final boolean atOverscrollEdge = overScrollBy(0, overscroll,
@@ -3582,6 +3590,10 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
        final MotionEvent vtev = MotionEvent.obtain(ev);



        final int actionMasked = ev.getActionMasked();

        if (actionMasked == MotionEvent.ACTION_DOWN) {

            mNestedYOffset = 0;

        }

        vtev.offsetLocation(0, mNestedYOffset);

        switch (actionMasked) {

            case MotionEvent.ACTION_DOWN: {

                onTouchDown(ev);
@@ -4144,7 +4156,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 


    @Override

    public boolean onInterceptTouchEvent(MotionEvent ev) {

        int action = ev.getAction();

        final int actionMasked = ev.getActionMasked();

        View v;



        if (mPositionScroller != null) {
@@ -4163,7 +4175,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            return true;

        }



        switch (action & MotionEvent.ACTION_MASK) {

        switch (actionMasked) {

        case MotionEvent.ACTION_DOWN: {

            int touchMode = mTouchMode;

            if (touchMode == TOUCH_MODE_OVERFLING || touchMode == TOUCH_MODE_OVERSCROLL) {
@@ -4190,6 +4202,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            mLastY = Integer.MIN_VALUE;

            initOrResetVelocityTracker();

            mVelocityTracker.addMovement(ev);

            mNestedYOffset = 0;

            startNestedScroll(SCROLL_AXIS_VERTICAL);

            if (touchMode == TOUCH_MODE_FLING) {

                return true;

core/java/android/widget/ScrollView.java

+11 −2
Original line number Diff line number Diff line
@@ -142,6 +142,7 @@ public class ScrollView extends FrameLayout { 
     */

    private final int[] mScrollOffset = new int[2];

    private final int[] mScrollConsumed = new int[2];

    private int mNestedYOffset;



    /**

     * The StrictMode "critical time span" objects to catch animation
@@ -516,6 +517,7 @@ public class ScrollView extends FrameLayout { 
                    mLastMotionY = y;

                    initVelocityTrackerIfNotExists();

                    mVelocityTracker.addMovement(ev);

                    mNestedYOffset = 0;

                    if (mScrollStrictSpan == null) {

                        mScrollStrictSpan = StrictMode.enterCriticalSpan("ScrollView-scroll");

                    }
@@ -586,9 +588,14 @@ public class ScrollView extends FrameLayout { 


        MotionEvent vtev = MotionEvent.obtain(ev);



        final int action = ev.getAction();

        final int actionMasked = ev.getActionMasked();



        switch (action & MotionEvent.ACTION_MASK) {

        if (actionMasked == MotionEvent.ACTION_DOWN) {

            mNestedYOffset = 0;

        }

        vtev.offsetLocation(0, mNestedYOffset);



        switch (actionMasked) {

            case MotionEvent.ACTION_DOWN: {

                if (getChildCount() == 0) {

                    return false;
@@ -630,6 +637,7 @@ public class ScrollView extends FrameLayout { 
                if (dispatchNestedPreScroll(0, deltaY, mScrollConsumed, mScrollOffset)) {

                    deltaY -= mScrollConsumed[1];

                    vtev.offsetLocation(0, mScrollOffset[1]);

                    mNestedYOffset += mScrollOffset[1];

                }

                if (!mIsBeingDragged && Math.abs(deltaY) > mTouchSlop) {

                    final ViewParent parent = getParent();
@@ -666,6 +674,7 @@ public class ScrollView extends FrameLayout { 
                    if (dispatchNestedScroll(0, scrolledDeltaY, 0, unconsumedY, mScrollOffset)) {

                        mLastMotionY -= mScrollOffset[1];

                        vtev.offsetLocation(0, mScrollOffset[1]);

                        mNestedYOffset += mScrollOffset[1];

                    } else if (canOverscroll) {

                        final int pulledToY = oldY + deltaY;

                        if (pulledToY < 0) {