Null object reference using setAudioAttributes

Question

I am trying make a radio streaming app in android studio using setAudioAttributes, but i when install the application in my phone shows the next error:

error java.lang.nullpointerexception: attempt to invoke virtual method void android.media.mediaplayer.setaudioattributes(android.media.AudioAttributes) on a null object reference

Thanks.

public class Radio extends Fragment {

Button play_pause;
MediaPlayer mp;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.radio, container, false);
    play_pause = (Button) view.findViewById(R.id.btnplay);
    try {
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {

            mp.setAudioAttributes(new AudioAttributes.Builder()
                    .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC).build());
            mp.setDataSource("http://198.27.83.65:9962/;stream.mp3");
            mp.prepare();
            mp.start();
        }
        else {
            Toast.makeText(getContext(),"Error",Toast.LENGTH_SHORT).show();
        }
     }
     catch (Exception e){
         Toast.makeText(getContext(),"Error" + e,Toast.LENGTH_SHORT).show();
     }
     //mp = MediaPlayer.create(this.getContext(), R.raw.radio);
        play_pause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                     if(mp.isPlaying()) {
                        mp.pause();
                        Toast.makeText(getContext(),"Stop",Toast.LENGTH_SHORT).show();
                    }
                    else {
                        mp.start();
                        Toast.makeText(getContext(),"Start",Toast.LENGTH_SHORT).show();
                    }
            }
        });
    return view;
}
}

Answer 1

Initialise your mp variable before using it. mp=new MediaPlayer();