title: Adding custom icon in rounded button
body: <p>How to add custom icon on rounded button?</p>
  
  <p>This is button:</p>
  
  <pre><code> &lt;Button
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:background="@drawable/selector_button"
    android:drawableTop="@android:drawable/ic_dialog_info"
    android:paddingTop="20dp"
    android:text="Contact"
    android:textColor="#fff" /&gt;
  </code></pre>
  
  <p>selector_button.xml</p>
  
  <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:drawable="@drawable/selector_button_pressed" android:state_enabled="true" android:state_pressed="true" /&gt;
  &lt;item android:drawable="@drawable/selector_button_pressed" android:state_activated="true" android:state_enabled="true" /&gt;
  &lt;item android:drawable="@drawable/selector_button_pressed" android:state_enabled="true" android:state_selected="true" /&gt;
  &lt;item android:drawable="@drawable/circle" /&gt; &lt;/selector&gt;
  </code></pre>
  
  <p>and this is shape for button:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;shape xmlns:android="http://schemas.android.com/apk/res/android"
      android:shape="rectangle"&gt;
      &lt;corners android:radius="1000dp" /&gt;
      &lt;solid android:color="#41ba7a" /&gt;
      &lt;stroke
          android:width="2dip"
          android:color="#03ae3c" /&gt;
      &lt;padding
          android:bottom="4dp"
          android:left="4dp"
          android:right="4dp"
          android:top="4dp" /&gt;
  &lt;/shape&gt;
  </code></pre>
  
  <p>In attribute </p>
  
  <blockquote>
    <p>android:drawableTop</p>
  </blockquote>
  
  <p>i can't find my custom image even it is visible in drawable folder.</p>