getActivity().getActionBar() is giving null on fragment

Question

I have a fragment , where I need to change the title of ActionBar dynamically. But when I am using the following code, it is giving me NullPointerException. Here getActionBar() is returning null,my question is how can I get the reference of ActionBar in Fragment class. Appreciate your help in advance.

Fragment Class code:

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

      ActionBar mActionBar = getActivity().getActionBar();
      mActionBar.setTitle("Your new score is :"+ i);
      return rootView;
}

Answer 1

I think the best solution is make a call back from your fragment like below:

Create a call back

public interface OnActionBarListener {
        void onChangeActionBarTitle(int score);
    }

and implement it in your activity

public class YourActivity extends AppCompatActivity
        implements OnActionBarListener {
    @Override
    public void onChangeActionBarTitle(int score) {
       mActionBar.setTitle("Your new score is :"+ score);
    }
}

and in your fragment

public class YourFragment extends Fragment {
    OnActionBarListener mListener;

 @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof YourActivity) {
            mListener = (OnActionBarListener) context;
        }

    }
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
       if (mListener != null) mListener.onChangeActionBarTitle(i);
       return rootView;
}

}

Hope this helps !

UPDATE 1: base on your request, if you want your activity listen every button click on your fragment, try below code in your fragment

Button mButton1;
Button mButton2;

mButton1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                changeTitle(your_score);
            }
        });
mButton2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                changeTitle(your_score);
            }
        });

void changeTitle(int score) {
        if (mListener != null) mListener.onChangeActionBarTitle(i);
    }