title: How to achieve ripple animation using support library?
body: <p>I am trying to add a ripple animation on button click. I did like below but it requires minSdKVersion to 21.</p>
  
  <p>ripple.xml</p>
  
  <pre><code>&lt;ripple xmlns:android="http://schemas.android.com/apk/res/android"
      android:color="?android:colorControlHighlight"&gt;
      &lt;item&gt;
          &lt;shape android:shape="rectangle"&gt;
              &lt;solid android:color="?android:colorAccent" /&gt;
          &lt;/shape&gt;
      &lt;/item&gt;
  &lt;/ripple&gt;
  </code></pre>
  
  <p>Button</p>
  
  <pre><code>&lt;com.devspark.robototextview.widget.RobotoButton
      android:id="@+id/loginButton"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@drawable/ripple"
      android:text="@string/login_button" /&gt;
  </code></pre>
  
  <p>I want to make it backward compatible with the design library.</p>
  
  <p>How this can be done?</p>