Material TabLayout elevation not working

To make the shadow show, you have to set a background on your TabLayout. It can be the same color as your window background (as long as it's a solid color with no alpha).

<android.support.design.widget.TabLayout    android:id="@+id/tab_layout"    android:layout_width="match_parent"    android:layout_height="?attr/actionBarSize"    android:elevation="6dp"    android:background="@color/white" />

You are supposed to use ToolBar with TabLayout. Then you can put them both inside an AppBarLayout and get a shadow. This only works on Lollipop+.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"              android:layout_width="match_parent"              android:layout_height="match_parent"              android:orientation="vertical">    <android.support.design.widget.AppBarLayout        android:id="@+id/appbar"        android:layout_width="match_parent"        android:layout_height="wrap_content">        <android.support.v7.widget.Toolbar            style="@style/ToolBarStyle"            android:id="@+id/toolbar"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:background="?attr/colorPrimary"            android:minHeight="@dimen/abc_action_bar_default_height_material"/>        <android.support.design.widget.TabLayout            android:id="@+id/tab_layout"            android:layout_width="match_parent"            android:layout_height="?attr/actionBarSize" />    </android.support.design.widget.AppBarLayout>    <android.support.v4.view.ViewPager        android:id="@+id/view_pager"        android:layout_width="match_parent"        android:layout_height="0dp"        android:layout_weight="1" /></LinearLayout>

See http://inthecheesefactory.com/blog/android-design-support-library-codelab/en

You'll need to use CoordinatorLayout as a container layout for your activity and then place your TabLayout right below AppBarLayout.According to Material Design specs you should use

android:elevation="4dp"

elevation and make your TabLayout be a part of AppBarLayout.Also note that elevation will only be visible on v21 (5.0) or higher.