How To Make Android Toolbar Elevation Working On Pre-Lollipop Devices

Step 1.

Make a material toolbar. (How To Make Material Design Actionbar/Toolbar In 7 Simple Steps)

Step 2.

Create a new drawable desource file  "shadow.xml".

1. <?xml version="1.0" encoding="utf-8"?>
2. <shape android:shape="rectangle" xmlns:android="http://schemas.android.com/apk/res/android">
3.     <gradient
4.         android:startColor="@android:color/transparent"
5.         android:endColor="#40000000"
6.         android:angle="90"/>
7. </shape>

Step 3.

Open "activity_main.xml" and add these lines between "include" and "RelativeLayout" Tags.

1. <FrameLayout
2.         android:layout_width="fill_parent"
3.         android:layout_height="4dp"
4.         android:background="@drawable/shadow"
5.         android:layout_below="@+id/toolbar"
6.         android:visibility="invisible" />

Now your "activity_main.xml" should look like this.

1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
2.     xmlns:tools="http://schemas.android.com/tools"
3.     android:layout_width="match_parent"
4.     android:layout_height="match_parent"
5.     tools:context=".MainActivity">
6.     <include
7.         android:id="@+id/toolbar"
8.         layout="@layout/toolbar"/>
9.     <FrameLayout
10.         android:layout_width="fill_parent"
11.         android:layout_height="4dp"
12.         android:background="@drawable/shadow"
13.         android:layout_below="@+id/toolbar"
14.         android:visibility="invisible" />
15.         <RelativeLayout
16.             android:layout_width="fill_parent"
17.             android:layout_height="fill_parent"
18.             android:layout_alignParentLeft="true"
19.             android:layout_alignParentStart="true"
20.             android:layout_below="@+id/toolbar"
21.             android:layout_alignParentRight="true"
22.             android:layout_alignParentEnd="true"
23.             android:layout_alignParentBottom="true"
24.             android:paddingLeft="@dimen/activity_horizontal_margin"
25.             android:paddingTop="@dimen/activity_vertical_margin"
26.             android:paddingRight="@dimen/activity_horizontal_margin"
27.             android:paddingBottom="@dimen/activity_vertical_margin">
28.             <TextView
29.                 android:layout_width="wrap_content"
30.                 android:layout_height="wrap_content"
31.                 android:text="@string/hello_world"
32.                 android:id="@+id/textView16" />
33.         </RelativeLayout>
34. </RelativeLayout>

Finally.

Run your application.