Add scroll indicators to GLIF Pixel theme

Add the scroll indicators to clearly indicate the divide between
status bar, content area, and footer, even though they all have the
same background color.

The scroll indicator will only be shown if there are content beyond
the fold.

Test: ./gradlew connectedAndroidTest test
Bug: 35446596
Change-Id: I5419e4f443a2414f8c983241b8fc61cadb48ef68

library/eclair-mr1/res/values/styles.xml

@@ -92,6 +92,7 @@
         <item name="suwItemDescriptionStyle">@style/SuwItemContainer.Description.Glif</item>
         <item name="suwListItemIconColor">@color/suw_list_item_icon_color_dark</item>
         <item name="suwMarginSides">@dimen/suw_glif_margin_sides</item>
+        <item name="suwScrollIndicators">none</item>
         <item name="textAppearanceListItem">@style/TextAppearance.SuwGlifItemTitle</item>
         <item name="textAppearanceListItemSmall">@style/TextAppearance.SuwGlifItemSummary</item>
     </style>
@@ -121,6 +122,7 @@
         <item name="suwItemDescriptionStyle">@style/SuwItemContainer.Description.Glif</item>
         <item name="suwListItemIconColor">@color/suw_list_item_icon_color_light</item>
         <item name="suwMarginSides">@dimen/suw_glif_margin_sides</item>
+        <item name="suwScrollIndicators">none</item>
         <item name="textAppearanceListItem">@style/TextAppearance.SuwGlifItemTitle</item>
         <item name="textAppearanceListItemSmall">@style/TextAppearance.SuwGlifItemSummary</item>
     </style>

library/full-support/res/layout/suw_glif_recycler_template_content.xml

@@ -18,17 +18,22 @@
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical">
 
+    <!-- Ignore UnusedAttribute: scrollIndicators is new in M. Default to no indicators in older
+         versions. -->
     <com.android.setupwizardlib.view.HeaderRecyclerView
         android:id="@+id/suw_recycler_view"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"
         android:scrollbars="vertical"
-        app:suwHeader="@layout/suw_glif_header" />
+        android:scrollIndicators="?attr/suwScrollIndicators"
+        app:suwHeader="@layout/suw_glif_header"
+        tools:ignore="UnusedAttribute" />
 
     <ViewStub
         android:id="@+id/suw_layout_footer"

library/main/res/layout/suw_glif_list_template_content.xml

@@ -17,17 +17,22 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical">
 
+    <!-- Ignore UnusedAttribute: scrollIndicators is new in M. Default to no indicators in older
+         versions. -->
     <com.android.setupwizardlib.view.StickyHeaderListView
         xmlns:app="http://schemas.android.com/apk/res-auto"
         android:id="@android:id/list"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"
-        app:suwHeader="@layout/suw_glif_header" />
+        android:scrollIndicators="?attr/suwScrollIndicators"
+        app:suwHeader="@layout/suw_glif_header"
+        tools:ignore="UnusedAttribute" />
 
     <ViewStub
         android:id="@+id/suw_layout_footer"

library/main/res/layout/suw_glif_template_content.xml

@@ -17,16 +17,21 @@
 
 <LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="vertical">
 
+    <!-- Ignore UnusedAttribute: scrollIndicators is new in M. Default to no indicators in older
+         versions. -->
     <ScrollView
         android:id="@+id/suw_scroll_view"
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"
-        android:fillViewport="true">
+        android:fillViewport="true"
+        android:scrollIndicators="?attr/suwScrollIndicators"
+        tools:ignore="UnusedAttribute">
 
         <LinearLayout
             android:layout_width="match_parent"

library/main/res/values/attrs.xml

@@ -49,6 +49,26 @@
     <attr name="suwNavBarTextColor" format="color" />
     <attr name="suwNavBarTheme" format="reference" />
 
+    <!-- Values copied from frameworks/base/core/res/res/values/attrs.xml -->
+    <attr name="suwScrollIndicators">
+        <!-- No scroll indicators are displayed. -->
+        <flag name="none" value="0x00" />
+        <!-- Displays top scroll indicator when view can be scrolled up. -->
+        <flag name="top" value="0x01" />
+        <!-- Displays bottom scroll indicator when vew can be scrolled down. -->
+        <flag name="bottom" value="0x02" />
+        <!-- Displays left scroll indicator when vew can be scrolled left. -->
+        <flag name="left" value="0x04" />
+        <!-- Displays right scroll indicator when vew can be scrolled right. -->
+        <flag name="right" value="0x08" />
+        <!-- Displays right scroll indicator when vew can be scrolled in the
+             start direction. -->
+        <flag name="start" value="0x10" />
+        <!-- Displays right scroll indicator when vew can be scrolled in the
+             end direction. -->
+        <flag name="end" value="0x20" />
+    </attr>
+
     <!-- Custom view attributes -->
     <attr name="suwColorPrimary" format="color" />
     <attr name="suwHeader" format="reference" />

library/main/res/values/styles.xml

@@ -25,6 +25,7 @@
         <item name="suwBackgroundBaseColor">?android:attr/colorBackground</item>
         <item name="suwBackgroundPatterned">false</item>
         <item name="suwGlifHeaderGravity">center_horizontal</item>
+        <item name="suwScrollIndicators">top|bottom</item>
     </style>
 
     <style name="SuwThemeGlifPixel.Light" parent="SuwThemeGlif.Light">
@@ -33,6 +34,7 @@
         <item name="suwBackgroundBaseColor">?android:attr/colorBackground</item>
         <item name="suwBackgroundPatterned">false</item>
         <item name="suwGlifHeaderGravity">center_horizontal</item>
+        <item name="suwScrollIndicators">top|bottom</item>
     </style>
 
     <style name="Animation.SuwWindowAnimation" parent="@android:style/Animation.Activity">

library/platform/res/values-v23/styles.xml

@@ -95,6 +95,7 @@
         <item name="suwItemDescriptionStyle">@style/SuwItemContainer.Description.Glif</item>
         <item name="suwListItemIconColor">@color/suw_list_item_icon_color_dark</item>
         <item name="suwMarginSides">@dimen/suw_glif_margin_sides</item>
+        <item name="suwScrollIndicators">none</item>
     </style>
 
     <style name="SuwThemeGlif.Light" parent="android:Theme.Material.Light.NoActionBar">
@@ -121,6 +122,7 @@
         <item name="suwItemDescriptionStyle">@style/SuwItemContainer.Description.Glif</item>
         <item name="suwListItemIconColor">@color/suw_list_item_icon_color_light</item>
         <item name="suwMarginSides">@dimen/suw_glif_margin_sides</item>
+        <item name="suwScrollIndicators">none</item>
     </style>
 
     <!-- Button styles -->

library/test/instrumentation/src/com/android/setupwizardlib/test/GlifLayoutTest.java

@@ -106,6 +106,12 @@ public class GlifLayoutTest {
                 Integer.toHexString(glifLayout.getBackgroundBaseColor().getDefaultColor()));
         assertFalse("GLIF Pixel theme shuold not have patterned background",
                 glifLayout.isBackgroundPatterned());
+
+        if (VERSION.SDK_INT >= VERSION_CODES.M) {
+            // Scroll indicators are only available on versions >= M
+            assertEquals(View.SCROLL_INDICATOR_TOP | View.SCROLL_INDICATOR_BOTTOM,
+                    glifLayout.getScrollView().getScrollIndicators());
+        }
     }
 
     private void assertDefaultTemplateInflated(GlifLayout layout) {