onDateChanged 方法似乎不起作用

 
public class DatePickerFragment extends DialogFragment {

    public static final String EXTRA_DATE = "thanoschatz.com.annastodolist.date";

    private Date mDate;

    public static DatePickerFragment newInstance(Date mDate) {
        Bundle args = new Bundle();
        args.putSerializable(EXTRA_DATE, mDate);

        DatePickerFragment fragment = new DatePickerFragment();
        fragment.setArguments(args);

        return fragment;
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        mDate = (Date) getArguments().getSerializable(EXTRA_DATE);


        Calendar calendar = Calendar.getInstance();
        calendar.setTime(mDate);
        int year = calendar.get(Calendar.YEAR);
        int month = calendar.get(Calendar.MONTH);
        int day = calendar.get(Calendar.DAY_OF_MONTH);

        View v = getActivity().getLayoutInflater().inflate(R.layout.dialog_date, null);

        DatePicker datePicker = (DatePicker) v.findViewById(R.id.dialog_date_datepicker);
        datePicker.init(year, month, day, new DatePicker.OnDateChangedListener() {
            @Override
            public void onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth) {

                mDate = new GregorianCalendar(year, monthOfYear, dayOfMonth).getTime();


                getArguments().putSerializable(EXTRA_DATE, mDate);
            }
        });

        return new AlertDialog.Builder(getActivity())
                .setView(v) //
                .setTitle(R.string.date_picker_title) //
                .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        sendResult(Activity.RESULT_OK);
                    }
                })
                .create();
    }

    private void sendResult(int resultCode) {
        if (getTargetFragment() == null) return;

        Intent intent = new Intent();
        intent.putExtra(EXTRA_DATE, mDate);

        getTargetFragment().onActivityResult(getTargetRequestCode(), resultCode, intent);
    }
}

 

public class ToDoFragment extends Fragment {
    public static final String EXTRA_TODO_ID = "thanoschatz.com.annastodolist.todo_id";
    private static final String DIALOG_DATE = "date";
    private static final int REQUEST_DATE = 0;

    private ToDo mToDo;
    private EditText mTitleField;
    private Button mDateButton;
    private CheckBox mDoneCheckBox;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
        UUID toDoId = (UUID)getArguments().getSerializable(EXTRA_TODO_ID);
        mToDo= ToDoLab.get(getActivity()).getToDo(toDoId);
    }



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_todo, container, false);
        wireTitleField(view);
        wireDateButton(view);
        wireSolvedCheckBox(view);
        return  view;
    }




    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (resultCode != Activity.RESULT_OK) {
            return;
        }
        if (requestCode == REQUEST_DATE) {
            Date mDate = (Date)intent.getSerializableExtra(DatePickerFragment.EXTRA_DATE);
            mToDo.setDate(mDate);
           
        }
    }

    public ToDoFragment(){

    }

    
    public static ToDoFragment newInstance(UUID mId) {
        Bundle args = new Bundle();
        args.putSerializable(EXTRA_TODO_ID, mId);

        ToDoFragment fragment = new ToDoFragment();
        fragment.setArguments(args);

        return fragment;
    }

  

    private void wireDateButton(View view) {
        SimpleDateFormat dateFormatter = getSimpleDateFormat();
        mDateButton = (Button)view.findViewById(R.id.toDo_date);
        updateDate(dateFormatter);

        mDateButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                FragmentManager fragmentManager = getFragmentManager();
                DatePickerFragment datePicker = DatePickerFragment.newInstance(mToDo.getDate());
                datePicker.setTargetFragment(ToDoFragment.this, REQUEST_DATE);
                datePicker.show(fragmentManager, DIALOG_DATE);
            }
        });
    }
}