title: how to add image at the center of LayerList android
body: <p>I am setting style to my splash screen activity and in style I am adding background gradient, Now I am trying to add image at the center of screen, actually just below the center of screen lets say 20dp below the center.
  can any one tell me how I can active it.</p>
  
  <p>Style I am adding to activity:</p>
  
  <pre><code>&lt;style name="SplashTheme" parent="Theme.AppCompat.Light.NoActionBar"&gt;
          &lt;item name="android:windowBackground"&gt;
              @drawable/background_splash
          &lt;/item&gt;
          &lt;item name="android:buttonStyle"&gt;
              @style/Base.Widget.AppCompat.Button.Colored
          &lt;/item&gt;
          &lt;item name="colorAccent"&gt;
              @color/white
          &lt;/item&gt;
          &lt;item name="colorPrimaryDark"&gt;
              @color/blue.dark
          &lt;/item&gt;
      &lt;/style&gt; 
  </code></pre>
  
  <p>background_splash.xml: please refer comment in file</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layer-list xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:drawable="@drawable/splash_screen_gradient" /&gt; 
  // here I want to add Image here such that it will be we wrap_contect and
  // 20dp below center of screen
  &lt;/layer-list&gt;
  </code></pre>
  
  <p>splash_screen_gradient.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layer-list xmlns:android="http://schemas.android.com/apk/res/android"
      &gt;
      &lt;item &gt;
          &lt;shape&gt;
              &lt;gradient
                  android:angle="270"
                  android:centerColor="#ff0000"
                  android:endColor="#00ff00"
                  android:startColor="#0000ff"&gt;
              &lt;/gradient&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  &lt;/layer-list&gt;
  </code></pre>
  
  <p>I have tried several permutation combinations by adding Bitmap, Item background in layer list but its not working as expected.
  I don't want to add it in layout xml file.  </p>