<uses-permission android:name="android.permission.EXPAND_STATUS_BAR"/>
<uses-permission android:name="android.permission.STATUS_BAR"/>

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    // TODO Auto-generated method stub
    super.onWindowFocusChanged(hasFocus);
    try {
      Object service = getSystemService("statusbar");
      Class<?> statusbarManager = Class.forName("android.app.StatusBarManager");
      Method test = statusbarManager.getMethod("collapse");
      test.invoke(service);
    } catch (Exception ex) {
      ex.printStackTrace();
    }
}