android - onAttach callback from fragment to activity

Question

I want to send String data from fragment to activity.

I have read the article about communicating between fragment and activity in android developer, using onAttach callback.

can anyone explain clearly how to send data from fragment to activity?

Answer 1

You should do something like this. First create an interface which will use to comunicate with your activity for example :

public interface OnViewSelected {
public void onViewSelected(int viewId);
}

and in your onAttach do this :

OnViewSelected _mClickListener;
@Override
public void onAttach(Context context) {
    super.onAttach(context);
    try {
        _mClickListener = (OnViewSelected) context;
    } catch (ClassCastException e) {
        throw new ClassCastException(context.toString() + " must implement onViewSelected");
    }
}

In your Fragment implement OnClickListener and in your onClick() method do this :

@Override
public void onClick(View v) {
    _mClickListener.onViewSelected(456);
}

After that in your Activity you have to implement the interface you created in your Fragment and it will ask you to add unimplemented methods and in your activity you will have function like this :

@Override
public void onViewSelected(int data) {
    Log.d("","data : "+data); // this value will be 456.
}

That's all. : )