i am getting only android actionbar overlaylayout in preview

xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/drawer_layout"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:fitsSystemWindows="true"
 tools:openDrawer="start">

    <include
 layout="@layout/app_bar_main"
 android:layout_width="match_parent"
 android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
 android:id="@+id/nav_view"
 android:layout_width="wrap_content"
 android:layout_height="match_parent"
 android:layout_gravity="start"
 android:fitsSystemWindows="true"
 app:headerLayout="@layout/nav_header_main"
 app:menu="@menu/activity_main_drawer" />

android.support.v4.widget.DrawerLayout>