Fragment与Activity的接口回调

private OnFragmentInteractionListener mListener;  
    
  @Override  
  public void onAttach(Context context) {  
      super.onAttach(context);  
      if (context instanceof OnFragmentInteractionListener) {  
          mListener = (OnFragmentInteractionListener) context;  
      }  
      else {  
          throw new RuntimeException(context.toString()  
                  + " must implement OnFragmentInteractionListener");  
      }  
  }  
  
  @Override  
  public void onDetach() {  
      super.onDetach();  
      mListener = null;  
  }  
  
  public interface OnFragmentInteractionListener {  
      // TODO: Update argument type and name  
      void onFragmentInteraction(String data);  
  }