Add elevation/shadow on toolbar for pre-lollipop devices

Try using the AppBarLayout inside the activity layout. Try:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

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

        <include
            layout="@layout/Toolbar" />
    </android.support.design.widget.AppBarLayout>

    <fragment
        class="OverAllField.XamarinAndroid.Fragments.Planning.PlanningFragment"
        android:id="@+id/PlanningFragment"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
</LinearLayout>

Toolbar.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/Toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

For Android 5.0 and above : AppBarLayout automatically provides/gives shadow in the layout. You can also increase the elevation of the AppBarLayout by app:elevation="4dp".

For Pre-Lollipop : You can use the following link: https://github.com/vipulasri/Toolbar-Elevation-Pre-Lollipop

Note: Toolbar also supports elevation to it, using android:elevation="4dp"

---

New Update: In Appcompat v24.0.0, you can not set elevation to AppBarLayout using setElevation() and app:elevation as these are deprecated.

You have to use stateListAnimator property to set elevation now.

Note: set duration to 1ms in StateListAnimator in order to avoid delay in Elevation Drawing.

AppBarLayout elevation change is delayed on appCompat v24.0.0

appbar_always_elevated.xml in animator-v21 folder under res directory.

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item>
    <objectAnimator android:propertyName="elevation"
                    android:valueTo="8dp" 
                    android:valueType="floatType"
                    android:duration="1"/>
</item>
</selector>

In AppbarLayout :

<android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:fitsSystemWindows="true"
        android:stateListAnimator="@animator/appbar_always_elevated"
        android:theme="@style/AppTheme.AppBarOverlay">

</android.support.design.widget.AppBarLayout>

use build file:

---

compile 'com.android.support:cardview-v7:23.1.1'

refer this link

to call in xml add:

app:cardElevation="8dp"
app:cardCornerRadius="8dp"
app:contentPadding="5dp"