SampleFragment.Java

public class SampleFragment extends Fragment implements OnClickListener {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.sample_fragment,container, false);
        Button nextButton = (Button) view.findViewById(R.id.button_first);
        nextButton.setOnClickListener(this);
        return view;
    }
  
    // ... some method of your fragment life cycle
}