Show toolbar shadow on pre-Lollipop

app/src/main/res/drawable/toolbar_shadow.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2016 Álinson Santos Xavier <isoron@gmail.com>
+  ~
+  ~ This file is part of Loop Habit Tracker.
+  ~
+  ~ Loop Habit Tracker is free software: you can redistribute it and/or modify
+  ~ it under the terms of the GNU General Public License as published by the
+  ~ Free Software Foundation, either version 3 of the License, or (at your
+  ~ option) any later version.
+  ~
+  ~ Loop Habit Tracker is distributed in the hope that it will be useful, but
+  ~ WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+  ~ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+  ~ more details.
+  ~
+  ~ You should have received a copy of the GNU General Public License along
+  ~ with this program. If not, see <http://www.gnu.org/licenses/>.
+  -->
+
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+       android:shape="rectangle">
+
+    <gradient android:startColor="@android:color/transparent"
+              android:endColor="@color/black"
+              android:angle="90"/>
+
+</shape>

app/src/main/res/layout/about.xml

@@ -191,4 +191,8 @@
         </LinearLayout>
     </ScrollView>
 
+    <View
+        android:id="@+id/toolbarShadow"
+        style="@style/ToolbarShadow"/>
+
 </RelativeLayout>

app/src/main/res/layout/list_habits_activity.xml

@@ -17,10 +17,10 @@
   ~ with this program. If not, see <http://www.gnu.org/licenses/>.
   -->
 
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
-                xmlns:tools="http://schemas.android.com/tools"
+<RelativeLayout android:id="@+id/container"
+                xmlns:android="http://schemas.android.com/apk/res/android"
                 xmlns:app="http://schemas.android.com/apk/res-auto"
-                android:id="@+id/container"
+                xmlns:tools="http://schemas.android.com/tools"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"
                 tools:context="org.isoron.uhabits.MainActivity"
@@ -28,15 +28,19 @@
 
     <android.support.v7.widget.Toolbar
         android:id="@+id/toolbar"
-        app:popupTheme="?toolbarPopupTheme"
-        style="@style/Toolbar"/>
+        style="@style/Toolbar"
+        app:popupTheme="?toolbarPopupTheme"/>
 
     <fragment
         android:id="@+id/fragment1"
         android:name="org.isoron.uhabits.fragments.ListHabitsFragment"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        tools:layout="@layout/list_habits_fragment"
-        android:layout_below="@id/toolbar"/>
+        android:layout_below="@id/toolbar"
+        tools:layout="@layout/list_habits_fragment"/>
+
+    <View
+        android:id="@+id/toolbarShadow"
+        style="@style/ToolbarShadow"/>
 
 </RelativeLayout>

app/src/main/res/layout/settings_activity.xml

@@ -39,4 +39,8 @@
         android:layout_gravity="center"
         android:layout_below="@id/toolbar"/>
 
+    <View
+        android:id="@+id/toolbarShadow"
+        style="@style/ToolbarShadow"/>
+
 </RelativeLayout>

app/src/main/res/layout/show_habit_activity.xml

@@ -42,4 +42,8 @@
         android:layout_gravity="center"
         android:layout_below="@id/toolbar"/>
 
+    <View
+        android:id="@+id/toolbarShadow"
+        style="@style/ToolbarShadow"/>
+
 </RelativeLayout>

app/src/main/res/values/styles.xml

@@ -222,4 +222,12 @@
     <style name="Preference.Category.Material">
         <item name="android:layout">@layout/preference_category_custom</item>
     </style>
+
+    <style name="ToolbarShadow">
+        <item name="android:layout_width">match_parent</item>
+        <item name="android:layout_height">3dp</item>
+        <item name="android:background">@drawable/toolbar_shadow</item>
+        <item name="android:alpha">0.25</item>
+        <item name="android:layout_below">@id/toolbar</item>
+    </style>
 </resources>