title: How to change the shape of Floating Action Button (FAB) on android?
body: <p>In our android app we need to create a floating action button which isn't the default circle but a square with with three rounded corners. The fab looks like in the image below: </p>
  
  <p><a href="https://i.stack.imgur.com/uAZiV.png" rel="noreferrer"><img src="https://i.stack.imgur.com/uAZiV.png" alt="enter image description here"></a></p>
  
  <p>I managed to create such a form but don't know how to apply it to my fab, or if it's even possible. The xml file for the shape looks like this:</p>
  
  <pre><code>   &lt;shape xmlns:android="http://schemas.android.com/apk/res/android"
        android:shape="rectangle"&gt;
      &lt;solid android:color="@color/red" /&gt;
      &lt;corners
        android:topLeftRadius="90dp"
        android:topRightRadius="90dp"
        android:bottomRightRadius="90dp"/&gt;
     &lt;/shape&gt;
  </code></pre>
  
  <p>I tried to change the form with </p>
  
  <pre><code>android:src="@drawable/my_shape"
  </code></pre>
  
  <p>but this changes only the icon inside my button. 
  I think I need to extend FloatingActionButton but I have no idea how.</p>
  
  <p>Is there a way to change the shape of the fab? If someone has already achieved this I would appreciate to see a sample.</p>