I ended up setting my own drop shadow for the toolbar, thought it might helpful for anyone looking for it:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"              xmlns:app="http://schemas.android.com/apk/res-auto"              android:layout_width="wrap_content"              android:layout_height="wrap_content"              android:layout_gravity="top"              android:orientation="vertical">    <android.support.v7.widget.Toolbar android:id="@+id/toolbar"                                       android:layout_width="match_parent"                                       android:layout_height="wrap_content"                                       android:background="@color/color_alizarin"                                       android:titleTextAppearance="@color/White"                                       app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>    <FrameLayout android:layout_width="match_parent"                 android:layout_height="match_parent">        <!-- **** Place Your Content Here **** -->        <View android:layout_width="match_parent"              android:layout_height="5dp"              android:background="@drawable/toolbar_dropshadow"/>    </FrameLayout></LinearLayout>

@drawable/toolbar_dropshadow:

<?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="#88333333"              android:angle="90"/></shape>

@color/color_alizarin

<color name="color_alizarin">#e74c3c</color>

Google released the Design Support library a few weeks ago and there is a nifty solution for this problem in this library.

Add the Design Support library as a dependency in build.gradle :

compile 'com.android.support:design:22.2.0'

Add AppBarLayout supplied by the library as a wrapper around your Toolbar layout to generate a drop shadow.

    <android.support.design.widget.AppBarLayout        android:layout_width="match_parent"        android:layout_height="wrap_content">       <android.support.v7.widget.Toolbar           .../>    </android.support.design.widget.AppBarLayout>

Here is the result :

There are lots of other tricks with the design support library.

1. http://inthecheesefactory.com/blog/android-design-support-library-codelab/en
2. http://android-developers.blogspot.in/2015/05/android-design-support-library.html

AndroidX

As above but with dependency:

implementation 'com.google.android.material:material:1.0.0'

and com.google.android.material.appbar.AppBarLayout

You can't use the elevation attribute before API 21 (Android Lollipop). You can however add the shadow programmatically, for example using a custom view placed below the Toolbar.

@layout/toolbar

<android.support.v7.widget.Toolbar    android:id="@+id/toolbar"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:background="@color/blue"    android:minHeight="?attr/actionBarSize"    app:theme="@style/ThemeOverlay.AppCompat.ActionBar" /><View    android:id="@+id/toolbar_shadow"    android:layout_width="match_parent"    android:layout_height="3dp"    android:background="@drawable/toolbar_dropshadow" />

@drawable/toolbar_dropshadow

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">    <gradient        android:startColor="@android:color/transparent"        android:endColor="#88333333"        android:angle="90"/> </shape>

in your activity layout <include layout="@layout/toolbar" />