title: How to maintain ripple effect when the button is selected
body: <p>I have a button with ripple effect, it has two states 
  one is "regular" with ripple effect and the other one is selected
  the background is changed but there are two issues:</p>
  
  <ol>
  <li>The hole button colored with color, I would like only to color the oval shape of the button</li>
  <li>The ripple effect not persist when changing the background color of the button</li>
  </ol>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
     &lt;item android:state_selected="true" android:drawable="@color/cal_selected"/&gt;
      &lt;item android:drawable="@drawable/cal_day_regualr"&gt;
          &lt;ripple xmlns:android="http://schemas.android.com/apk/res/android" android:color="?android:attr/colorActivatedHighlight"&gt;
              &lt;item android:id="@android:id/mask"&gt;
                  &lt;shape android:shape="oval"&gt;
                      &lt;solid android:color="@color/cal_background" /&gt;
                  &lt;/shape&gt;
              &lt;/item&gt;
          &lt;/ripple&gt;
      &lt;/item&gt;
  &lt;/selector&gt;
  </code></pre>