android - 如何在两个 fragment 之间传递数据？

Question

我有两个 Activity 和两个 fragment :detialActivity 和 detialActivityFragment、mainActivity 和 mainActivityFragment。 我如何在 detialActivityFragment 和 mainActivityFragment 之间传递数据。 当我尝试传递数据时显示异常:java.lang.NullPointerException 我做了界面:

  public interface OnButtonPressListener { 
        public void onButtonPressed(String msg);
    }

在类 mainActivityFragment 中:

 @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
           try {
                buttonListener = (OnButtonPressListener) getActivity();
            } catch (ClassCastException e) {
                throw new ClassCastException(activity.toString() + " must 
                implement onButtonPressed");
            }
        }

  public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View root = inflater.inflate(R.layout.fragment_main, container, 
        false);
        listMovie = (GridView) root.findViewById(R.id.gridview_movie);

        listMovie.setOnItemClickListener(new  AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                buttonListener.onButtonPressed("hi");
            }
        });
        return root;
    }

内部类 detialActivityFragment:

void setMessage(String msg){
   TextView txt=(TextView)root.findViewById(R.id.titleDetialMovie);
   txt.setText(msg);
}

内部类 detialActivity:

 @Override
    public void onButtonPressed(String msg) {
        DetialActivityFragment Obj=(DetialActivityFragment)                   
   getSupportFragmentManager().findFragmentById(R.id.detialActivityFragment);
        Obj.setMessage(msg);
    }

Answer 1

你不应该这样调用方法。 而是将数据传递给 Fragment 的构造函数并在那里使用它。