我正在制作在线媒体播放器应用程序。它工作得很好bt，当我单击“下一步”按钮时无法播放下一首歌曲

Question

I am making online media player app.. it works very well but I am unable to play next song when I click the next button

PLAYER CLASS

public class Player extends AppCompatActivity {

    Intent i;
    String sname,sid,spath;
    ImageButton play;
    Button nxt;
    MediaPlayer mp;
    ArrayList list;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.player);

        play = (ImageButton)findViewById(R.id.play_pause);


        nxt = (Button) findViewById(R.id.next);

        nxt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            // NO IDEA WHAT TO DO NOW
            }
        });

        play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mp = MediaPlayer.create(Player.this,Uri.parse(spath));


                if(mp.isPlaying()){
                    if(mp!=null){
                        mp.pause();
                        // Changing button image to play button
                        play.setImageResource(R.drawable.uamp_ic_play_arrow_white_48dp);
                    }
                }else{
                    // Resume song
                    if(mp!=null){
                        mp.start();
                        // Changing button image to pause button
                        play.setImageResource(R.drawable.uamp_ic_pause_white_48dp);
                    }
                }
        }
        });

        i=getIntent();

        sid=i.getStringExtra("sid");
        sname=i.getStringExtra("sname");
        spath=i.getStringExtra("spath");

    }
    @Override
    public void onBackPressed() {
        startActivity(new Intent(Player.this, song_list.class));
        finish();
        super.onBackPressed();
    }
}

SONGLIST CLASS

public class song_list extends AppCompatActivity  {

    ListView listView;
    ArrayList<pojonew> list;
    String result,url;
    json js;


    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.song_list);

        listView = (ListView)findViewById(R.id.songs);


        url="https://heeled-pipe.000webhostapp.com/select.php";
        new SongData().execute();


        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                pojonew p=(pojonew)list.get(position);
                String sid=p.getId();
                String sname=p.getName();
                String spath=p.getPath();
                Intent i = new Intent(song_list.this,Player.class);
                i.putExtra("sid",sid);
                i.putExtra("sname",sname);
                i.putExtra("spath",spath);
                startActivity(i);
            }
        });

    }

SONGDATA CLASS

    class SongData extends AsyncTask<Void, Void , Void>
    {


        @Override
        protected Void doInBackground(Void... params) {
            js = new json();
            list = new ArrayList<>();
            result = js.getdatafromurl(url);

            Log.d("url",url);

            try {
                JSONObject jo = new JSONObject(result);

                JSONArray ja= jo.getJSONArray("data");
                for (int i=0;i<ja.length();i++){
                    JSONObject jo1 = ja.getJSONObject(i);
                    pojonew sp = new pojonew();
                    sp.setId(jo1.getString("id"));
                    sp.setName(jo1.getString("name"));
                    sp.setPath(jo1.getString("path"));

                    list.add(sp);

                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            custadapter n=new custadapter(list,song_list.this);
            listView.setAdapter(n);
        }
    }
}

Answer 1

on click of the play get the position of list data item and call the method below

    public ModelClass loadNext(String id) {
    ModelClass nextAudio = null;

    int pos = 1;
    for (int index = 0; index < FileList.size(); index++) {
        if (ModelClass.get(index).getFileUID().equals(id)) {
            pos = index + 1;
            break;
        }
    }

    if (pos != AudioFileList.size())
        nextAudio = AudioFileList.get(pos);

    return nextAudio;
}

load media player has your playing in on click of list view