DialogFragment show with tag doesn't work correctly

Question

I've created TimePicker using this manual http://developer.android.com/guide/topics/ui/controls/pickers.html

public class TimePickerFragment extends DialogFragment {

    private TimePickerDialog.OnTimeSetListener mListener;
    private Activity mActivity;
    private Calendar mCalendar = Calendar.getInstance();

    public TimePickerFragment(Activity a,TimePickerDialog.OnTimeSetListener listener) {
        mListener = listener;
        mActivity = a;
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current time as the default values for the picker
        int hour = mCalendar.get(Calendar.HOUR_OF_DAY);
        int minute = mCalendar.get(Calendar.MINUTE);

        // Create a new instance of TimePickerDialog and return it
        return new TimePickerDialog(mActivity, mListener, hour, minute,
                DateFormat.is24HourFormat(mActivity));
    }
}

I'm trying to show this Dialog with tag this way

public class SomeActivity extends FragmentActivity implements TimePickerDialog.OnTimeSetListener {
    TimePickerFragment mTimePicker;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.some_view);

        mTimePicker = new TimePickerFragment(this, this);

        // calling show with "SOME_TAG" tag
        mTimePicker.show(this.getSupportFragmentManager(), "SOME_TAG");
    }

    @Override
    public void onTimeSet(TimePicker timePicker, int hourOfDay, int minute) {
        // Here tag is null ?!
        // Why?
        String tag = (String) timePicker.getTag();
    }
}

But in the onTimeSet method, tag is always null. Why?

Answer 1

you can simply get tag by getTag() function

public static class DatePickerCustom extends DialogFragment implements
            DatePickerDialog.OnDateSetListener {
        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            final Calendar calendar = Calendar.getInstance();
            int yy = calendar.get(Calendar.YEAR);
            int mm = calendar.get(Calendar.MONTH);
            int dd = calendar.get(Calendar.DAY_OF_MONTH);
            return new DatePickerDialog(getActivity(), this, yy, mm, dd);
        }

        public void onDateSet(DatePicker view, int yy, int mm, int dd) {

              String mytag=getTag();

        }
    }

Answer 2

I know its a late reply but i went through with the same condition recently . So here is my answer ,

the DialogFragment.Show(FragmentManager manager, String tag) method is set tag for Fragment itself . so this tag can be use as follows :

Fragment dateTo=getActivity().getSupportFragmentManager().findFragmentByTag("dateTo");
            if(dateTo!=null){
                //do something

            } 

one use case is you can display more then one fragment in a activity and to identify the fragment you can find that fragment with the given tag.If it is not null, bingo!!!