title: Get the app icon as int identifier
body: <p>I want to retrieve the icon of an app. If I use</p>
  
  <pre><code>String pkg = "com.app.my";
  Drawable icon = getContext().getPackageManager().getApplicationIcon(pkg);
  </code></pre>
  
  <p>The result is a Drawable. how can I retrieve the id of the associated resource for passing it as extra in an intent? THanks!</p>