title: android get button background imageName programmatically
body: <p>I'm using button in layout.xml as following</p>
  
  <pre><code> &lt;Button
        android:id="@+id/karaza"
        android:layout_width="160dp"
        android:layout_height="160dp"
        android:background="@drawable/button_green"
        android:text="0"
        android:textColor="#FFFFFF"
        android:textSize="45dp" /&gt;
  </code></pre>
  
  <p>The background image name is "button_green"</p>
  
  <p>how can I get it in the code of activity as String?</p>
  
  <p>Thanks in advance</p>