title: How to make a circular ripple on a button when it's being clicked?
body: <h2>Background</h2>
  
  <p>On the dialer app of Android, when you start searching for something, and you click the arrow button on the left of the EditText, you get a circular ripple effect on it :</p>
  
  <p><a href="https://i.stack.imgur.com/1q30Y.png"><img src="https://i.stack.imgur.com/1q30Y.png" alt="enter image description here"></a></p>
  
  <h2>The problem</h2>
  
  <p>I've tried to have it too, but I got a rectangular one:</p>
  
  <pre><code>    &lt;ImageButton
          android:id="@+id/navButton"
          android:layout_width="40dp"
          android:layout_height="40dp"
          android:layout_gravity="center_vertical"
          android:layout_marginLeft="8dp"
          android:background="?android:attr/selectableItemBackground"
          android:src="@drawable/search_ic_back_arrow"/&gt;
  </code></pre>
  
  <h2>The question</h2>
  
  <p>How do I make the button have a circular ripple effect when being clicked? Do I have to create a new drawable, or is there a built in way for that?</p>