Toolbar Elevation on Pre-lollipop Devices.

As we know Lollipop devices gives us a nice shadow by default, but pre Lollipop doesn’t.
Now so to overcome this problem and apply Elevation/Shadow on Pre-lollipop devices.

1. Firstly, we will create a drawable to imitate elevation/shadow

Create a new XML file dropshadow.xml in directory res/drawable

    <?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
        <gradient
            android:startColor="@android:color/transparent"
            android:endColor="#44000000"
            android:angle="90"/>
    </shape>

2. We will add the shadow drawable below toolbar

    <LinearLayout 
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary" />

    <View
        android:layout_width="match_parent"
        android:layout_height="4dp"
        android:background="@drawable/dropshadow" />

    </LinearLayout>

You also can create a another Toolbar in a separate XML file and call it in xml via the <include/> tag.

Ex. <include layout="@layout/toolbar_shadow" />

Result