title: Mask for Ripple effect drawable
body: <p>I have used ripple effect on a view:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;ripple xmlns:android="http://schemas.android.com/apk/res/android"
      android:color="@android:color/black"&gt;
  
      &lt;item&gt;
          &lt;shape android:shape="oval"&gt;
              &lt;solid android:color="?android:colorAccent" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  
      &lt;item&gt;
          &lt;shape android:shape="oval"&gt;
              &lt;stroke
                  android:width="2dp"
                  android:color="@android:color/white" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  &lt;/ripple&gt;
  </code></pre>
  
  <p>Problem is when I click on button, borders effected as well which I specified with 2dp width as stroke.</p>
  
  <p>To fix the problem I used <code>android:id="@android:id/mask"</code> for the first item in ripple drawable as specified in <a href="https://developer.android.com/reference/android/graphics/drawable/RippleDrawable.html" rel="nofollow">documentation</a>. But it just remove the color of item from button.</p>
  
  <p>So then how can I mask ripple effect for specific item and not all child layers?</p>
  
  <p>I tried it in on Android with Lolipop version as well as Marshmallow.</p>