@SuppressWarnings("unchecked")

     public <T extends Fragment> T getFragment(int id) {

         T result = (T)getFragmentManager().findFragmentById(id);

         if (result == null) {

             throw new IllegalArgumentException("fragment 0x" + Integer.toHexString(id)

                     + " doesn't exist");

         }

         return result;

     }

     /**

      * Convenient version of {@link #findViewById(int)}, which throws

      * an exception if the view doesn't exist.

      */

     @SuppressWarnings("unchecked")

     public <T extends View> T getView(int id) {

         T result = (T)findViewById(id);

         if (result == null) {

             throw new IllegalArgumentException("view 0x" + Integer.toHexString(id)

                     + " doesn't exist");

         }

         return result;

     }