Scroll the hiding page to top on tab changed in sharesheet

After the tab changed, ResolverDrawerLayout will lose reference of the
hidden page which can cause the page not able to scoll back to top.
Automatically scroll on tab changed to avoid that situation.

Bug: 160886554
Test: manually test; atest ChooserActivityTest; atest
ResolverActivityTest

Change-Id: I1a8ba72f6b1dcb9bca19262b97983788001d715b

2 files changed, 13 insertions, 5 deletions

diff --git a/core/java/com/android/internal/app/ChooserActivity.java b/core/java/com/android/internal/app/ChooserActivity.java
index fbf050ad08f6..3a89dcd96487 100644
--- a/core/java/com/android/internal/app/ChooserActivity.java
+++ b/core/java/com/android/internal/app/ChooserActivity.java
@@ -3134,6 +3134,7 @@ public class ChooserActivity extends ResolverActivity implements
         // ends up disabled. That's because at some point the old tab's vertical scrolling is
         // disabled and the new tab's is enabled. For context, see b/159997845
         setVerticalScrollEnabled(true);
+        mResolverDrawerLayout.scrollNestedScrollableChildBackToTop();
     }
 
     @Override
diff --git a/core/java/com/android/internal/widget/ResolverDrawerLayout.java b/core/java/com/android/internal/widget/ResolverDrawerLayout.java
index 3f708f84750c..90eeabb47e9a 100644
--- a/core/java/com/android/internal/widget/ResolverDrawerLayout.java
+++ b/core/java/com/android/internal/widget/ResolverDrawerLayout.java
@@ -464,11 +464,7 @@ public class ResolverDrawerLayout extends ViewGroup {
                             smoothScrollTo(mCollapsibleHeight + mUncollapsibleHeight, yvel);
                             mDismissOnScrollerFinished = true;
                         } else {
-                            if (isNestedListChildScrolled()) {
-                                mNestedListChild.smoothScrollToPosition(0);
-                            } else if (isNestedRecyclerChildScrolled()) {
-                                mNestedRecyclerChild.smoothScrollToPosition(0);
-                            }
+                            scrollNestedScrollableChildBackToTop();
                             smoothScrollTo(yvel < 0 ? 0 : mCollapsibleHeight, yvel);
                         }
                     }
@@ -493,6 +489,17 @@ public class ResolverDrawerLayout extends ViewGroup {
         return handled;
     }
 
+    /**
+     * Scroll nested scrollable child back to top if it has been scrolled.
+     */
+    public void scrollNestedScrollableChildBackToTop() {
+        if (isNestedListChildScrolled()) {
+            mNestedListChild.smoothScrollToPosition(0);
+        } else if (isNestedRecyclerChildScrolled()) {
+            mNestedRecyclerChild.smoothScrollToPosition(0);
+        }
+    }
+
     private void onSecondaryPointerUp(MotionEvent ev) {
         final int pointerIndex = ev.getActionIndex();
         final int pointerId = ev.getPointerId(pointerIndex);