Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 92ce8508 authored by Pawit Pornkitprasan's avatar Pawit Pornkitprasan
Browse files

Improve scrolling cache 

Scrolling cache helps make short scrolls/flings smooth but will
cause stutter when long flings are made. This patch disables
scrolling cache when long flings are made.

This patch also fixes a related bug where scrolling cache will
not be enabled properly when transitioning from flinging to scrolling.

Patch Set 2: Calculate threshold based on maximum velocity (Sang Tae Park)

Change-Id: I1fdbaad92263c9f983a32900e74eba1f0367902b
parent 11638519

core/java/android/widget/AbsListView.java

+14 −2
Original line number Diff line number Diff line
@@ -567,6 +567,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
    private Runnable mClearScrollingCache;

    private int mMinimumVelocity;

    private int mMaximumVelocity;

    private int mDecacheThreshold;

    private float mVelocityScale = 1.0f;



    final boolean[] mIsScrap = new boolean[1];
@@ -786,6 +787,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
        mTouchSlop = configuration.getScaledTouchSlop();

        mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();

        mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();

        mDecacheThreshold = mMaximumVelocity / 2;

        mOverscrollDistance = configuration.getScaledOverscrollDistance();

        mOverflingDistance = configuration.getScaledOverflingDistance();
@@ -3650,7 +3652,7 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
                    // Keep the fling alive a little longer

                    postDelayed(this, FLYWHEEL_TIMEOUT);

                } else {

                    endFling();

                    endFling(false); // Don't disable the scrolling cache right after it was enabled

                    mTouchMode = TOUCH_MODE_SCROLL;

                    reportScrollStateChange(OnScrollListener.SCROLL_STATE_TOUCH_SCROLL);

                }
@@ -3664,6 +3666,11 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
        }



        void start(int initialVelocity) {

            if (Math.abs(initialVelocity) > mDecacheThreshold) {

                // For long flings, scrolling cache causes stutter, so don't use it

                clearScrollingCache();

            }



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

            mLastFlingY = initialY;

            mScroller.fling(0, initialY, 0, initialVelocity,
@@ -3733,12 +3740,17 @@ public abstract class AbsListView extends AdapterView<ListAdapter> implements Te 
        }



        void endFling() {

            endFling(true);

        }



        void endFling(boolean clearCache) {

            mTouchMode = TOUCH_MODE_REST;



            removeCallbacks(this);

            removeCallbacks(mCheckFlywheel);



            reportScrollStateChange(OnScrollListener.SCROLL_STATE_IDLE);

            if (clearCache)

                clearScrollingCache();

            mScroller.abortAnimation();