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Commit b9cda5fd authored by Kirill Grouchnikov's avatar Kirill Grouchnikov
Browse files

Tweaking scroll-related functionality of AbsListView 

* Only firing scroll state change to IDLE at the end of the
sequence of emulated mini-fling operations.
* Clarifying the behavior of scrollListBy

Bug: 30114090
Change-Id: I3fe1f851a99ac6392be664be11ca3e05d57ed764
parent b25c0d97

core/java/android/widget/AbsListView.java

+41 −16
Original line number Diff line number Diff line
@@ -3003,8 +3003,9 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            setChildrenDrawingCacheEnabled(false);

            if (mFlingRunnable != null) {

                removeCallbacks(mFlingRunnable);

                // let the fling runnable report it's new state which

                // let the fling runnable report its new state which

                // should be idle

                mFlingRunnable.mSuppressIdleStateChangeCall = false;

                mFlingRunnable.endFling();

                if (mPositionScroller != null) {

                    mPositionScroller.stop();
@@ -4555,6 +4556,12 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
         */

        private int mLastFlingY;



        /**

         * If true, {@link #endFling()} will not report scroll state change to

         * {@link OnScrollListener#SCROLL_STATE_IDLE}.

         */

        private boolean mSuppressIdleStateChangeCall;



        private final Runnable mCheckFlywheel = new Runnable() {

            @Override

            public void run() {
@@ -4593,6 +4600,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            mScroller.fling(0, initialY, 0, initialVelocity,

                    0, Integer.MAX_VALUE, 0, Integer.MAX_VALUE);

            mTouchMode = TOUCH_MODE_FLING;

            mSuppressIdleStateChangeCall = false;

            postOnAnimation(this);



            if (PROFILE_FLINGING) {
@@ -4608,6 +4616,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
        }



        void startSpringback() {

            mSuppressIdleStateChangeCall = false;

            if (mScroller.springBack(0, mScrollY, 0, 0, 0, 0)) {

                mTouchMode = TOUCH_MODE_OVERFLING;

                invalidate();
@@ -4623,6 +4632,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            mScroller.fling(0, mScrollY, 0, initialVelocity, 0, 0,

                    Integer.MIN_VALUE, Integer.MAX_VALUE, 0, getHeight());

            mTouchMode = TOUCH_MODE_OVERFLING;

            mSuppressIdleStateChangeCall = false;

            invalidate();

            postOnAnimation(this);

        }
@@ -4649,12 +4659,14 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            postOnAnimation(this);

        }



        void startScroll(int distance, int duration, boolean linear) {

        void startScroll(int distance, int duration, boolean linear,

                boolean suppressEndFlingStateChangeCall) {

            int initialY = distance < 0 ? Integer.MAX_VALUE : 0;

            mLastFlingY = initialY;

            mScroller.setInterpolator(linear ? sLinearInterpolator : null);

            mScroller.startScroll(0, initialY, 0, distance, duration);

            mTouchMode = TOUCH_MODE_FLING;

            mSuppressIdleStateChangeCall = suppressEndFlingStateChangeCall;

            postOnAnimation(this);

        }
@@ -4664,7 +4676,9 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            removeCallbacks(this);

            removeCallbacks(mCheckFlywheel);



            if (!mSuppressIdleStateChangeCall) {

                reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);

            }

            clearScrollingCache();

            mScroller.abortAnimation();
@@ -4907,10 +4921,11 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
     * @param duration Duration of the scroll animation in milliseconds.

     */

    public void smoothScrollBy(int distance, int duration) {

        smoothScrollBy(distance, duration, false);

        smoothScrollBy(distance, duration, false, false);

    }



    void smoothScrollBy(int distance, int duration, boolean linear) {

    void smoothScrollBy(int distance, int duration, boolean linear,

            boolean suppressEndFlingStateChangeCall) {

        if (mFlingRunnable == null) {

            mFlingRunnable = new FlingRunnable();

        }
@@ -4932,7 +4947,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            }

        } else {

            reportScrollStateChange(OnScrollListener.SCROLL_STATE_FLING);

            mFlingRunnable.startScroll(distance, duration, linear);

            mFlingRunnable.startScroll(distance, duration, linear, suppressEndFlingStateChangeCall);

        }

    }
@@ -5006,6 +5021,9 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
    /**

     * Scrolls the list items within the view by a specified number of pixels.

     *

     * <p>The actual amount of scroll is capped by the list content viewport height

     * which is the list height minus top and bottom paddings minus one pixel.</p>

     *

     * @param y the amount of pixels to scroll by vertically

     * @see #canScrollList(int)

     */
@@ -7367,7 +7385,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
            } else {

                // On-screen, just scroll.

                final int targetTop = getChildAt(mTargetPos - firstPos).getTop();

                smoothScrollBy(targetTop - offset, duration, true);

                smoothScrollBy(targetTop - offset, duration, true, false);

                return;

            }
@@ -7467,7 +7485,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                        Math.max(mListPadding.bottom, mExtraScroll) : mListPadding.bottom;



                final int scrollBy = lastViewHeight - lastViewPixelsShowing + extraScroll;

                smoothScrollBy(scrollBy, mScrollDuration, true);

                smoothScrollBy(scrollBy, mScrollDuration, true, lastPos < mTargetPos);



                mLastSeenPos = lastPos;

                if (lastPos < mTargetPos) {
@@ -7482,6 +7500,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 


                if (firstPos == mBoundPos || childCount <= nextViewIndex

                        || firstPos + childCount >= mItemCount) {

                    reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);

                    return;

                }

                final int nextPos = firstPos + nextViewIndex;
@@ -7498,14 +7517,16 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                final int extraScroll = Math.max(mListPadding.bottom, mExtraScroll);

                if (nextPos < mBoundPos) {

                    smoothScrollBy(Math.max(0, nextViewHeight + nextViewTop - extraScroll),

                            mScrollDuration, true);

                            mScrollDuration, true, true);



                    mLastSeenPos = nextPos;



                    postOnAnimation(this);

                } else  {

                    if (nextViewTop > extraScroll) {

                        smoothScrollBy(nextViewTop - extraScroll, mScrollDuration, true);

                        smoothScrollBy(nextViewTop - extraScroll, mScrollDuration, true, false);

                    } else {

                        reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);

                    }

                }

                break;
@@ -7526,7 +7547,8 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                final int extraScroll = firstPos > 0 ?

                        Math.max(mExtraScroll, mListPadding.top) : mListPadding.top;



                smoothScrollBy(firstViewTop - extraScroll, mScrollDuration, true);

                smoothScrollBy(firstViewTop - extraScroll, mScrollDuration, true,

                        firstPos > mTargetPos);



                mLastSeenPos = firstPos;
@@ -7556,13 +7578,16 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                final int extraScroll = Math.max(mListPadding.top, mExtraScroll);

                mLastSeenPos = lastPos;

                if (lastPos > mBoundPos) {

                    smoothScrollBy(-(lastViewPixelsShowing - extraScroll), mScrollDuration, true);

                    smoothScrollBy(-(lastViewPixelsShowing - extraScroll), mScrollDuration, true,

                            true);

                    postOnAnimation(this);

                } else {

                    final int bottom = listHeight - extraScroll;

                    final int lastViewBottom = lastViewTop + lastViewHeight;

                    if (bottom > lastViewBottom) {

                        smoothScrollBy(-(bottom - lastViewBottom), mScrollDuration, true);

                        smoothScrollBy(-(bottom - lastViewBottom), mScrollDuration, true, false);

                    } else {

                        reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);

                    }

                }

                break;
@@ -7595,12 +7620,12 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                if (position < firstPos) {

                    final int distance = (int) (-getHeight() * modifier);

                    final int duration = (int) (mScrollDuration * modifier);

                    smoothScrollBy(distance, duration, true);

                    smoothScrollBy(distance, duration, true, true);

                    postOnAnimation(this);

                } else if (position > lastPos) {

                    final int distance = (int) (getHeight() * modifier);

                    final int duration = (int) (mScrollDuration * modifier);

                    smoothScrollBy(distance, duration, true);

                    smoothScrollBy(distance, duration, true, true);

                    postOnAnimation(this);

                } else {

                    // On-screen, just scroll.
@@ -7608,7 +7633,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                    final int distance = targetTop - mOffsetFromTop;

                    final int duration = (int) (mScrollDuration *

                            ((float) Math.abs(distance) / getHeight()));

                    smoothScrollBy(distance, duration, true);

                    smoothScrollBy(distance, duration, true, false);

                }

                break;

            }