title: Why I get a red exclamation in android studio when I try to use setBackgroundResource?
body: <p>When I try to change the background of my button with</p>
  
  <pre><code>button.setBackgroundResource(R.drawable.button_orange);
  </code></pre>
  
  <p>I get a red exclamation in Line numbers , is it because the minimum sdk version is 15?  should someone worry? What should I do for that?</p>