title: How to hide the taskbar or set it to transparent in scrolling activity?
body: <p>I'm learning <em>ScrollingActivity</em> in Android and I met difficulty for handling the taskbar (the indigo part at the top). I want my zoo image take all the space, until it reaches the top of the screen. But I don't know how to do it. Can somebody help ?</p>
  
  <p><a href="https://i.stack.imgur.com/6BVbs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6BVbs.png" alt="screen shot"></a></p>
  
  <p>Here's the layout XML file <code>activity_scrolling</code>:</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"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:fitsSystemWindows="true"
      tools:context="com.example.zoo.activity.ScrollingActivity"&gt;
  
      &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/app_bar"
          android:layout_width="match_parent"
          android:layout_height="@dimen/app_bar_height"
          android:fitsSystemWindows="true"
          android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
          &lt;android.support.design.widget.CollapsingToolbarLayout
              android:id="@+id/toolbar_layout"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:fitsSystemWindows="true"
              app:contentScrim="?attr/colorPrimary"
              app:layout_scrollFlags="scroll|exitUntilCollapsed"&gt;
  
              &lt;ImageView
                  android:id="@+id/image"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent"
                  android:scaleType="centerCrop"
                  android:src="@drawable/bg_zoo"
                  app:layout_collapseMode="parallax"
                  app:layout_collapseParallaxMultiplier="0.7"/&gt;
  
              &lt;View
                  android:layout_width="match_parent"
                  android:layout_height="match_parent"
                  android:layout_marginTop="30dp"
                  android:background="@drawable/main_header_selector"
                  app:layout_collapseMode="parallax"
                  app:layout_collapseParallaxMultiplier="0.1"/&gt;
  
              &lt;android.support.v7.widget.Toolbar
                  android:id="@+id/toolbar"
                  android:layout_width="match_parent"
                  android:layout_height="?attr/actionBarSize"
                  app:layout_collapseMode="pin"
                  app:popupTheme="@style/AppTheme.PopupOverlay" /&gt;
  
          &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
      &lt;include layout="@layout/content_scrolling" /&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:id="@+id/fab"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_margin="@dimen/fab_margin"
          android:src="@android:drawable/ic_dialog_email"
          app:layout_anchor="@id/app_bar"
          app:layout_anchorGravity="bottom|end" /&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>This is what I want :</p>
  
  <p><a href="https://i.stack.imgur.com/BTlGJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BTlGJ.png" alt="should-be layout"></a></p>