From a9283beebc0755bbbc4b40d38530c2fdc33e2532 Mon Sep 17 00:00:00 2001
From: Vadim Tryshev <vadimt@google.com>
Date: Tue, 1 May 2018 19:22:37 -0700
Subject: [PATCH] Settling scrolls over clear-all button.

Per UX feedback, we divide the "overscroll area" 50/50 and settle to the
closest of the most recent task position and the fully scrolled
position.

Bug: 72222505
Test: Manual
Change-Id: Ic98fa5ae2f14f274f6a425ac687f13f7b3a4332e
---
 src/com/android/launcher3/PagedView.java | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index 8311ab9a76..87ee076f36 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -1171,11 +1171,19 @@ public abstract class PagedView<T extends View & PageIndicator> extends ViewGrou
                     mNextPage = getPageNearestToCenterOfScreen(unscaledScrollX);
                     int firstPageScroll = getScrollForPage(!mIsRtl ? 0 : getPageCount() - 1);
                     int lastPageScroll = getScrollForPage(!mIsRtl ? getPageCount() - 1 : 0);
-                    if (mSettleOnPageInFreeScroll && unscaledScrollX > firstPageScroll
-                            && unscaledScrollX < lastPageScroll) {
-                        // Make sure we land directly on a page. If flinging past one of the ends,
-                        // don't change the velocity as it will get stopped at the end anyway.
-                        mScroller.setFinalX((int) (getScrollForPage(mNextPage) * getScaleX()));
+                    if (mSettleOnPageInFreeScroll && unscaledScrollX > 0
+                            && unscaledScrollX < mMaxScrollX) {
+                        // If scrolling ends in the half of the added space that is closer to the
+                        // end, settle to the end. Otherwise snap to the nearest page.
+                        // If flinging past one of the ends, don't change the velocity as it will
+                        // get stopped at the end anyway.
+                        final int finalX = unscaledScrollX < firstPageScroll / 2 ?
+                                0 :
+                                unscaledScrollX > (lastPageScroll + mMaxScrollX) / 2 ?
+                                        mMaxScrollX :
+                                        getScrollForPage(mNextPage);
+
+                        mScroller.setFinalX((int) (finalX * getScaleX()));
                         // Ensure the scroll/snap doesn't happen too fast;
                         int extraScrollDuration = OVERSCROLL_PAGE_SNAP_ANIMATION_DURATION
                                 - mScroller.getDuration();