title: Robotium ClickOnButton(int ID) method causes "junit.framework.AssertionFailedError: Button with index 2131034130 is not available!"
body: <p>I am using robotium for testing and can't figure out how to click buttons without text.
  Test fails with trace:</p>
  
  <blockquote>
    <p>junit.framework.AssertionFailedError: Button with index 2131034130 is not available!</p>
  </blockquote>