title: Android combine Drawable and Shape into a single Drawable (programatically)
body: <p>I'm setting <code>android:drawable</code> of a RadioButton programatically like this:</p>
  
  <pre><code>Drawable unchecked = getResources().getDrawable(R.drawable.ic_room_car);
  
  Drawable d= getResources().getDrawable(R.drawable.ic_room_car);
  
  Shape circle = ?????;
  ??? checked = combine circle and d
  
  
  SateListDrawable states= new StateListDrawable();
  states.addState(new int[] {android.R.attr.state_checked}, checked);
  states.addState(new int[] {}, unchecked);
  
  ((RadioButton)findViewById(R.id.icon_1)).setButtonDrawable(states);
  </code></pre>
  
  <p>Basically it has a custom icon that I'm reading from resources when it's unchecked, and when checked I would like to draw a circle behind the icon. </p>
  
  <p>The unchecked behavior is set in the second addState line, and it's working. My problem is how to draw a circle programatically and then somehow combine it with the drawable I'm reading from resources.</p>