From b1d629dc71f6f7eda06963053f27564856a29449 Mon Sep 17 00:00:00 2001
From: Matt Pietal <mpietal@google.com>
Date: Tue, 23 Apr 2019 11:35:53 -0400
Subject: [PATCH] Sharesheet - Scrolling UI adjustments

Add elevation on scroll for 'scroll under' effect. Remove scrollbars.

Bug: 129979914
Test: Visual inspection
Change-Id: Ia2fd19fc2fd2f3f2e966991e8a907f25c6925df9
---
 .../android/internal/app/ChooserActivity.java | 22 +++++++++++++++++++
 core/res/res/layout/chooser_grid.xml          |  4 ++--
 core/res/res/values/dimens.xml                |  1 +
 core/res/res/values/symbols.xml               |  2 ++
 4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/core/java/com/android/internal/app/ChooserActivity.java b/core/java/com/android/internal/app/ChooserActivity.java
index be66de22cdcf3..674c611eb88d9 100644
--- a/core/java/com/android/internal/app/ChooserActivity.java
+++ b/core/java/com/android/internal/app/ChooserActivity.java
@@ -479,6 +479,28 @@ public class ChooserActivity extends ResolverActivity {
             if (isSendAction(target)) {
                 mResolverDrawerLayout.setOnScrollChangeListener(this::handleScroll);
             }
+
+            final View chooserHeader = mResolverDrawerLayout.findViewById(R.id.chooser_header);
+            final float defaultElevation = chooserHeader.getElevation();
+            final float chooserHeaderScrollElevation =
+                    getResources().getDimensionPixelSize(R.dimen.chooser_header_scroll_elevation);
+
+            mAdapterView.setOnScrollListener(new AbsListView.OnScrollListener() {
+                public void onScrollStateChanged(AbsListView view, int scrollState) {
+                }
+
+                public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,
+                        int totalItemCount) {
+                    if (view.getChildCount() > 0) {
+                        if (firstVisibleItem > 0 || view.getChildAt(0).getTop() < 0) {
+                            chooserHeader.setElevation(chooserHeaderScrollElevation);
+                            return;
+                        }
+                    }
+
+                    chooserHeader.setElevation(defaultElevation);
+                }
+            });
         }
 
         if (DEBUG) {
diff --git a/core/res/res/layout/chooser_grid.xml b/core/res/res/layout/chooser_grid.xml
index 4d5e262d83006..8727f4c9e0ef3 100644
--- a/core/res/res/layout/chooser_grid.xml
+++ b/core/res/res/layout/chooser_grid.xml
@@ -25,6 +25,7 @@
     android:id="@id/contentPanel">
 
     <RelativeLayout
+        android:id="@+id/chooser_header"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_alwaysShow="true"
@@ -62,11 +63,10 @@
         android:layout_height="match_parent"
         android:id="@+id/resolver_list"
         android:clipToPadding="false"
-        android:scrollbarStyle="outsideOverlay"
         android:background="?attr/colorBackgroundFloating"
+        android:scrollbars="none"
         android:listSelector="@color/transparent"
         android:divider="@null"
-        android:scrollIndicators="top"
         android:elevation="1dp"
         android:nestedScrollingEnabled="true"/>
 
diff --git a/core/res/res/values/dimens.xml b/core/res/res/values/dimens.xml
index b81db158082c5..95a5ae6c84b80 100644
--- a/core/res/res/values/dimens.xml
+++ b/core/res/res/values/dimens.xml
@@ -729,5 +729,6 @@
     <dimen name="resolver_icon_size">42dp</dimen>
     <dimen name="resolver_badge_size">18dp</dimen>
     <dimen name="chooser_target_width">90dp</dimen>
+    <dimen name="chooser_header_scroll_elevation">4dp</dimen>
     <dimen name="chooser_max_collapsed_height">288dp</dimen>
 </resources>
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index 186b84ceb2557..719fd2f7aa166 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -2784,6 +2784,8 @@
   <java-symbol type="dimen" name="chooser_preview_image_border"/>
   <java-symbol type="dimen" name="chooser_max_collapsed_height" />
   <java-symbol type="layout" name="chooser_grid" />
+  <java-symbol type="id" name="chooser_header" />
+  <java-symbol type="dimen" name="chooser_header_scroll_elevation" />
   <java-symbol type="layout" name="chooser_grid_preview_text" />
   <java-symbol type="layout" name="chooser_grid_preview_image" />
   <java-symbol type="layout" name="chooser_grid_preview_file" />