title: Can't make the Window of my Activity translucent
body: <p>I'm trying to make my <code>Activity</code> translucent, i.e. see-through, but it's not working. It's always opaque. That's my code so far:</p>
  
  <pre><code>public class SvetlinTranslucentActivity extends Activity {
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          Window w = getWindow();
          w.setFormat(PixelFormat.RGBA_8888);
          w.addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
          w.setBackgroundDrawable(new ColorDrawable(0x00FF0000));
      }
  }
  </code></pre>
  
  <p>I've been looking at the code from the official API demos but still no success.</p>