DatePickerDialog listener

Question

I am making an Android app where I use a DatePickerDialog. The intended function is for the user to select a date in the dialog, and then for a TextView to reflect that chosen date. However, I can't find any sort of a click listener to notify my Activity when the user has selected a date. I am looking for a way to detect when the user has selected a date, but from my main Activity. This is my DatePickerDialog class:

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

private GregorianCalendar date;

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    // Use the current date as the default date in the picker
    final Calendar c = Calendar.getInstance();
    int year = c.get(Calendar.YEAR);
    int month = c.get(Calendar.MONTH);
    int day = c.get(Calendar.DAY_OF_MONTH);

    // Create a new instance of DatePickerDialog and return it
    return new DatePickerDialog(getActivity(), this, year, month, day);
}

@Override
public void onDateSet(DatePicker datePicker, int year, int month, int day) {
    date = new GregorianCalendar(year, month, day);
}

public GregorianCalendar getDate() {
    return date;
}
}    

And the code where I launch the dialog:

DialogFragment datePicker = new DatePickerFragment();
datePicker.show(getSupportFragmentManager(), "datePicker");

I currently launch the dialog from a class that extends Activity, and I am looking for a way to detect from within that class if a user has selected a date from the dialog. Any suggestions?

Answer 1

I recommend reading: Communicating with Other Fragments.

Activity has to implement DatePickerDialog.OnDateSetListener interface:

public class MyActivity extends ActionBarActivity implements DatePickerDialog.OnDateSetListener {
    ...

    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
        // the user selected, now you can do whatever you want with it
    }
}

Activity will be notified when user selected date if you add following code to DialogPickerFragment class:

public class DatePickerFragment extends DialogFragment {
    private DatePickerDialog.OnDateSetListener mListener;

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current date as the default date in the picker
        final Calendar c = Calendar.getInstance();
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DAY_OF_MONTH);

        // Create a new instance of DatePickerDialog and return it
        return new DatePickerDialog(getActivity(), mListener, year, month, day);
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);

        if (!(context instanceof DatePickerDialog.OnDateSetListener)) {
            throw new IllegalStateException("Activity must implement fragment's callbacks.");
        }

        mListener = (DatePickerDialog.OnDateSetListener) activity;
    }

    @Override
    public void onDetach() {
        super.onDetach();

        mListener = null;
    }
}