Returning String from Dialog Fragment back to Activity [duplicate]

Question

I have read many posts on this but I can't find any that apply to this case.

I have a time picker dialog and I have put the integer values together in a string and I need to get this string back to the main activity.

This string value will then be used to set the text of a button.

If someone could help me with this it would be most appreciated.

Thank you

Dialog Fragment

public class TimePickerFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener {     @Override     public Dialog onCreateDialog(Bundle savedInstanceState) {         // Use the current time as the default values for the picker         final Calendar c = Calendar.getInstance();         int hour = c.get(Calendar.HOUR_OF_DAY);         int minute = c.get(Calendar.MINUTE);          // Create a new instance of TimePickerDialog and return it         return new TimePickerDialog(getActivity(), this, hour, minute, DateFormat.is24HourFormat(getActivity()));     }      public void onTimeSet(TimePicker view, int hourOfDay, int minute) {         // Do something with the time chosen by the user         String Time =Integer.toString(hourOfDay) + " : " + Integer.toString(minute);     } } 

Code

@Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_second);           Button btn = (Button) findViewById(R.id.start_time_button);         Button.setText(Time);       } 

Answer 1

The preferred method is to use a callback to get a signal from a Fragment. Also, this is the recommended method proposed by Android at Communicating with the Activity

For your example, in your DialogFragment, add an interface and register it.

public static interface OnCompleteListener {     public abstract void onComplete(String time); }  private OnCompleteListener mListener;  // make sure the Activity implemented it @Override public void onAttach(Activity activity) {     super.onAttach(activity);      try {         this.mListener = (OnCompleteListener)activity;     }     catch (final ClassCastException e) {         throw new ClassCastException(activity.toString() + " must implement OnCompleteListener");     } } 

Now implement this interface in your Activity

public class MyActivity extends Activity implements MyDialogFragment.OnCompleteListener {     //...      public void onComplete(String time) {         // After the dialog fragment completes, it calls this callback.         // use the string here     } } 

Now in your DialogFragment, when a user clicks the OK button, send that value back to the Activity via your callback.

public void onTimeSet(TimePicker view, int hourOfDay, int minute) {     String time = Integer.toString(hourOfDay) + " : " + Integer.toString(minute);     this.mListener.onComplete(time); }