From c6d3ac2385b42e1bc939313a4283e8d28db477b3 Mon Sep 17 00:00:00 2001
From: Matt Pietal <mpietal@google.com>
Date: Thu, 25 Apr 2019 14:38:30 -0400
Subject: [PATCH] Sharesheet - Modify header scrolling behavior

To align with UX, scroll the listview before the header when
collapsing the sharesheet to its minified state, on both flings and
drags. Fix an issue with the expansion area, whereby state is only
updated if view positions are actually updated.

Bug: 129979914
Test: Visual inspection
Change-Id: I2e32a1a3288a21bcd3ce07819f77760f10d5d929
---
 .../android/internal/app/ChooserActivity.java | 13 ++++++----
 .../internal/widget/ResolverDrawerLayout.java | 26 +++++++++++++++++--
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/core/java/com/android/internal/app/ChooserActivity.java b/core/java/com/android/internal/app/ChooserActivity.java
index ca2bc7f586c9e..26e47fd6657c1 100644
--- a/core/java/com/android/internal/app/ChooserActivity.java
+++ b/core/java/com/android/internal/app/ChooserActivity.java
@@ -3042,10 +3042,9 @@ public class ChooserActivity extends ResolverActivity {
             int yDiff = (int) ((oldy - y) * DIRECT_SHARE_EXPANSION_RATE);
 
             int prevHeight = mDirectShareCurrHeight;
-            mDirectShareCurrHeight = Math.min(mDirectShareCurrHeight + yDiff,
-                    mDirectShareMaxHeight);
-            mDirectShareCurrHeight = Math.max(mDirectShareCurrHeight, mDirectShareMinHeight);
-            yDiff = mDirectShareCurrHeight - prevHeight;
+            int newHeight = Math.min(prevHeight + yDiff, mDirectShareMaxHeight);
+            newHeight = Math.max(newHeight, mDirectShareMinHeight);
+            yDiff = newHeight - prevHeight;
 
             if (view == null || view.getChildCount() == 0 || yDiff == 0) {
                 return;
@@ -3062,7 +3061,7 @@ public class ChooserActivity extends ResolverActivity {
                     if (child.getTag() != null && child.getTag() instanceof DirectShareViewHolder) {
                         int widthSpec = MeasureSpec.makeMeasureSpec(child.getWidth(),
                                 MeasureSpec.EXACTLY);
-                        int heightSpec = MeasureSpec.makeMeasureSpec(mDirectShareCurrHeight,
+                        int heightSpec = MeasureSpec.makeMeasureSpec(newHeight,
                                 MeasureSpec.EXACTLY);
                         child.measure(widthSpec, heightSpec);
                         child.getLayoutParams().height = child.getMeasuredHeight();
@@ -3073,6 +3072,10 @@ public class ChooserActivity extends ResolverActivity {
                     }
                 }
             }
+
+            if (foundExpansion) {
+                mDirectShareCurrHeight = newHeight;
+            }
         }
     }
 
diff --git a/core/java/com/android/internal/widget/ResolverDrawerLayout.java b/core/java/com/android/internal/widget/ResolverDrawerLayout.java
index 66bbe22c9969e..6b0d85ef0b95c 100644
--- a/core/java/com/android/internal/widget/ResolverDrawerLayout.java
+++ b/core/java/com/android/internal/widget/ResolverDrawerLayout.java
@@ -114,6 +114,8 @@ public class ResolverDrawerLayout extends ViewGroup {
 
     private final Rect mTempRect = new Rect();
 
+    private AbsListView mNestedScrollingChild;
+
     private final ViewTreeObserver.OnTouchModeChangeListener mTouchModeChangeListener =
             new ViewTreeObserver.OnTouchModeChangeListener() {
                 @Override
@@ -317,6 +319,13 @@ public class ResolverDrawerLayout extends ViewGroup {
         return mIsDragging || mOpenOnClick;
     }
 
+    private boolean isNestedChildScrolled() {
+        return mNestedScrollingChild != null
+                && mNestedScrollingChild.getChildCount() > 0
+                && (mNestedScrollingChild.getFirstVisiblePosition() > 0
+                        || mNestedScrollingChild.getChildAt(0).getTop() < 0);
+    }
+
     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         final int action = ev.getActionMasked();
@@ -359,7 +368,11 @@ public class ResolverDrawerLayout extends ViewGroup {
                 }
                 if (mIsDragging) {
                     final float dy = y - mLastTouchY;
-                    performDrag(dy);
+                    if (dy > 0 && isNestedChildScrolled()) {
+                        mNestedScrollingChild.smoothScrollBy((int) -dy, 0);
+                    } else {
+                        performDrag(dy);
+                    }
                 }
                 mLastTouchY = y;
             }
@@ -411,6 +424,9 @@ public class ResolverDrawerLayout extends ViewGroup {
                             smoothScrollTo(mCollapsibleHeight + mUncollapsibleHeight, yvel);
                             mDismissOnScrollerFinished = true;
                         } else {
+                            if (isNestedChildScrolled()) {
+                                mNestedScrollingChild.smoothScrollToPosition(0);
+                            }
                             smoothScrollTo(yvel < 0 ? 0 : mCollapsibleHeight, yvel);
                         }
                     }
@@ -680,7 +696,13 @@ public class ResolverDrawerLayout extends ViewGroup {
 
     @Override
     public boolean onStartNestedScroll(View child, View target, int nestedScrollAxes) {
-        return (nestedScrollAxes & View.SCROLL_AXIS_VERTICAL) != 0;
+        if ((nestedScrollAxes & View.SCROLL_AXIS_VERTICAL) != 0) {
+            if (child instanceof AbsListView) {
+                mNestedScrollingChild = (AbsListView) child;
+            }
+            return true;
+        }
+        return false;
     }
 
     @Override