title: Transparent bottom sheet layout in Android
body: <p>I am trying to make a transparent bottom sheet layout, that would allow me to see the contents of the view below it. The bottom sheet is working as expected, however when I set the background to either <code>@null</code> or <code>@android:color/transparent</code>, the layout's view is white, as opposed to transparent. My layout is as follows:</p>
  
  <p>app_bar_main.xml:</p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout 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:layout_width="match_parent"
      android:layout_height="match_parent"
      android:id="@+id/coordinatorLayout"
      android:background="@android:color/transparent"
      android:fitsSystemWindows="true"
      tools:context=".core.activities.MainActivity"&gt;
      &lt;!-- stuff here --&gt;
      &lt;LinearLayout
          android:id="@+id/bottom_sheet"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:gravity="center"
          android:background="@null"
          android:orientation="vertical"
          app:layout_behavior="@string/bottom_sheet_behavior"&gt;
      &lt;/LinearLayout&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>The linear layout with id <code>bottom_sheet</code> holds, well, my bottom sheet. The sheet itself is defined as follows:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.design.widget.CoordinatorLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:background="@null"
      android:layout_height="match_parent"&gt;
      &lt;LinearLayout android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:background="@null"
          android:orientation="vertical"&gt;
  
          &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/bottom_sheet_placeholder_layout"
              android:layout_weight="0.6"
              android:layout_width="match_parent"
              android:background="@null"
              android:layout_height="50dp"
              android:orientation="horizontal"&gt;
          &lt;/LinearLayout&gt;
          &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:id="@+id/bottom_sheet_layout"
              android:layout_margin="0dp"
              android:layout_weight="0.4"
              android:layout_width="match_parent"
              android:background="@color/my_background"
              android:layout_height="wrap_content"
              android:orientation="vertical"&gt;
  
              &lt;ProgressBar
                  android:layout_width="match_parent"
                  android:layout_height="wrap_content"
                  android:gravity="center"
                  android:id="@+id/my_progress_bar" /&gt;
  
              &lt;TextView
                  android:layout_marginTop="5dp"
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:textAppearance="?android:attr/textAppearanceLarge"
                  android:text="Large Text"
                  android:textColor="@color/my_text"
                  android:id="@+id/txt_my_info"
                  android:layout_gravity="center_horizontal"
                  android:visibility="gone"
                  android:textSize="48px" /&gt;
  
              &lt;TextView
                  android:layout_width="wrap_content"
                  android:layout_height="wrap_content"
                  android:textAppearance="?android:attr/textAppearanceMedium"
                  android:text="Medium Text"
                  android:id="@+id/txt_my_address"
                  android:textColor="@color/my_secondary_text"
                  android:visibility="gone"
                  android:layout_gravity="center_horizontal" /&gt;
          &lt;/LinearLayout&gt;
      &lt;/LinearLayout&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:id="@+id/btn_edit_tree_info"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:clickable="true"
          android:layout_marginTop="-62dp"
          android:elevation="100dp"
          android:src="@drawable/ic_create_black_24dp"
          app:layout_anchor="@id/bottom_sheet_layout"
          app:layout_anchorGravity="top|end|right"
          app:useCompatPadding="true"/&gt;
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>