Fix overdraw and do some layout optimizations

- use a specific layout for the Dashboard and for the Preferences
- use a specific background for the Dashboard and for the Preferences

The main idea here is that you cannot have the same layout / background
because the Dashboard is using the "Z elevation" for having its card
"poping up"

Change-Id: I42b7c91efea14315b8a60cf3876938a7f1d1e0b3

res/layout/preference_list_fragment.xml

@@ -36,8 +36,6 @@
               android:scrollbarStyle="@*android:integer/preference_fragment_scrollbarStyle"
               android:clipToPadding="false"
               android:drawSelectorOnTop="false"
-              android:cacheColorHint="@android:color/white"
-              android:background="@drawable/preference_list_fragment_background"
               android:elevation="@dimen/dashboard_category_elevation"
               android:scrollbarAlwaysDrawVerticalTrack="true" />
 
@@ -82,6 +80,8 @@
                     android:text="@*android:string/next_button_label"
                     />
         </LinearLayout>
+
     </RelativeLayout>
+
 </LinearLayout>
 

res/layout/settings_main_dashboard.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/*
+** Copyright 2014, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+-->
+
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+             android:id="@+id/main_content"
+             android:layout_height="match_parent"
+             android:layout_width="match_parent"
+             android:background="@color/dashboard_background_color"
+             />

res/layout/settings_main_prefs.xml

@@ -20,8 +20,7 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
               android:orientation="vertical"
               android:layout_height="match_parent"
-              android:layout_width="match_parent"
-              android:background="?attr/dashboardBackgroundColor">
+              android:layout_width="match_parent">
 
     <LinearLayout
             android:orientation="vertical"
@@ -37,9 +36,10 @@
                 />
 
         <FrameLayout
-                android:id="@+id/prefs"
+                android:id="@+id/main_content"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"
+                android:background="?attr/preferenceBackgroundColor"
                 />
 
     </LinearLayout>