title: NavigationDrawer with Background image
body: <p>I want to have an image in the background of the drawer <strong>behind the menu</strong>. In this piece of code the <strong>image is in front of the menu</strong>. Im not sure, but I cannot use a FrameLayout in this particular case.</p>
  
  <p>The image should also <strong>maintain its aspect ratio</strong> and the <strong>semitransparent color</strong> should stay in front of it. This color is provided by the @color/menuSemi</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;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"&gt;
  
      &lt;include
          layout="@layout/content_main"
          android:layout_width="match_parent"
          android:layout_height="match_parent"/&gt;
  
      &lt;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"
          android:background="@color/menuSemi"
          app:itemTextColor="@color/white"
          app:itemIconTint="@color/white"
          android:paddingTop="16dp"
          style="@style/AppTheme.navigation"
          app:menu="@menu/activity_main"&gt;
  
          &lt;RelativeLayout
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:layout_gravity="start"&gt;
  
              &lt;ImageView
                  android:id="@+id/drawer_bg"
                  android:src="@drawable/sidebar"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent"
                  android:alpha="1"
                  android:scaleType="centerCrop"/&gt;
          &lt;/RelativeLayout&gt;
  
      &lt;/android.support.design.widget.NavigationView&gt;
  &lt;/android.support.v4.widget.DrawerLayout&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/FBkRY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FBkRY.png" alt="Result of this markup"></a></p>