Get date from datepicker using dialogfragment

Question

I'm using the google example to insert a datepicker inside my app using a dialogfragment
http://developer.android.com/guide/topics/ui/controls/pickers.html

But I'm not sure how to get date after set it (not java expert). Dialog and datepicker runs ok and I can log that date is correctely set but, how can i do to get a callback executed on parent activity?

This is my Dialog fragment

public class DatePickerFragment extends DialogFragment implements
        DatePickerDialog.OnDateSetListener {

    @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);
    }

    public void onDateSet(DatePicker view, int year, int month, int day) {
        **Log.w("DatePicker","Date = " + year);**
    }
}

...and I call dialog from my activity with...

public void showDatePickerDialog(View v) {
    DialogFragment newFragment = new DatePickerFragment();
    newFragment.show(getSupportFragmentManager(), "datePicker");
}

What is the correct way to call a method in my parent activity instead Log.w? I suppose that is something related with passing a callback as parameter or something but most of references I found on internet are about previous versions without dialogfragments

EDIT: not sure if it's important but parent activity is declared as:

public class EditSessionActivity extends FragmentActivity {

SOLUTION: thanks to Lecho user this is the way to do it

DatePickerFragmennt.class

public class DatePickerFragment extends DialogFragment{

    @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(), (EditSessionActivity)getActivity(), year, month, day);
    }

}

...and parent activity EditSessionActivity.class...

public class EditSessionActivity extends FragmentActivity implements OnDateSetListener {
...
    @Override
    public void onDateSet(DatePicker view, int year, int month, int day) {
        //do some stuff for example write on log and update TextField on activity
        Log.w("DatePicker","Date = " + year);
        ((EditText) findViewById(R.id.tf_date)).setText("Date = " + year);
    }

user_5730321 · Answer

In case you have to return a result to a Fragment, but not an Activity, here is a complete solution:

public class DatePickerDialogFragment extends DialogFragment  {

    private static final String ARGUMENT_YEAR = "ARGUMENT_YEAR";
    private static final String ARGUMENT_MONTH = "ARGUMENT_MONTH";
    private static final String ARGUMENT_DAY = "ARGUMENT_DAY";
    private DatePickerDialog.OnDateSetListener listener;

    private int year;
    private int month;
    private int dayOfMonth;

    public static DatePickerDialogFragment newInstance(final int year, final int month, final int dayOfMonth) {
        final DatePickerDialogFragment df = new DatePickerDialogFragment();
        final Bundle args = new Bundle();
        args.putInt(ARGUMENT_YEAR, year);
        args.putInt(ARGUMENT_MONTH, month);
        args.putInt(ARGUMENT_DAY, dayOfMonth);
        df.setArguments(args);
        return df;
    }

    @Override
    public void onCreate(@Nullable final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        retrieveArguments();
    }

    private void retrieveArguments() {
        final Bundle args = getArguments();
        if (args != null) {
            year = args.getInt(ARGUMENT_YEAR);
            month = args.getInt(ARGUMENT_MONTH);
            dayOfMonth = args.getInt(ARGUMENT_DAY);
        }
    }

    @Override
    public Dialog onCreateDialog(final Bundle savedInstanceState) {
        return new DatePickerDialog(getContext(), this.listener, this.year, this.month, this.dayOfMonth);
    }

    public void setListener(final DatePickerDialog.OnDateSetListener listener) {
        this.listener = listener;
    }
}

Then just use it in a Fragment or in an Activity:

final Calendar c = Calendar.getInstance();
DatePickerDialogFragment datePicker = DatePickerDialogFragment.newInstance(
        c.get(Calendar.YEAR),
        c.get(Calendar.MONTH),
        c.get(Calendar.DAY_OF_MONTH));
datePicker.setListener(this);
datePicker.show(getChildFragmentManager(), null);

user_4225163 · Answer

Kotlin version.

DatePickerFragment class:

class DatePickerFragment : DialogFragment() {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {

        val c = Calendar.getInstance()
        val year = c.get(Calendar.YEAR)
        val month = c.get(Calendar.MONTH)
        val day = c.get(Calendar.DAY_OF_MONTH)

        return DatePickerDialog(context!!, context!! as MainActivity, year, month, day)
    }
}

DatePickerDialog.OnDateSetListener is moved to MainActicity

class MainActivity : AppCompatActivity(), DatePickerDialog.OnDateSetListener {

    ..

    override fun onDateSet(view: DatePicker, year: Int, month: Int, day: Int) {
        //use date in your activity
    }
}

Get date from datepicker using dialogfragment

9 Answers