SurfaceView播放视频发送弹幕并实现滚动歌词

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback {
  
  public static final int PROGRESS = 101;

  SurfaceView surfaceView,surfaceView_danmu;
  SurfaceHolder surfaceHolder,surfaceView_danmuHolder;
  MediaPlayer mediaPlayer = new MediaPlayer();
  String path = "/sdcard/aa.mp4";
  SeekBar seekBar;
  Timer timer;
  EditText editText;
  Button button,bt_start,bt_stop;
  int x = 0;

  ArrayList<DanMu> list = new ArrayList<>();
  Handler handler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
      super.handleMessage(msg);
      if (msg.what == PROGRESS){
        seekBar.setProgress((Integer) msg.obj);
        mediaPlayer.setOnSeekCompleteListener(new MediaPlayer.OnSeekCompleteListener() {
          @Override
          public void onSeekComplete(MediaPlayer mp) {
            Toast.makeText(MainActivity.this, "播放完毕！", Toast.LENGTH_SHORT).show();
          }
        });
      }
    }
  };

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

    surfaceView = findViewById(R.id.sufaceview);
    surfaceView_danmu = findViewById(R.id.sufaceview_danmu);
    editText = findViewById(R.id.et);
    button = findViewById(R.id.bt_send);
    seekBar = findViewById(R.id.bar);
    bt_start = findViewById(R.id.bt_start);
    bt_stop = findViewById(R.id.bt_stop);

    surfaceHolder = surfaceView.getHolder();
    surfaceHolder.addCallback(this);

    surfaceView_danmuHolder = surfaceView_danmu.getHolder();
    surfaceView_danmuHolder.addCallback(this);
    surfaceView_danmu.setZOrderOnTop(true);
    surfaceView_danmuHolder.setFormat(PixelFormat.TRANSPARENT);

    if (mediaPlayer!=null) {
      try {
        mediaPlayer.setDataSource(path);
        mediaPlayer.prepareAsync();
        mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
          @Override
          public void onPrepared(MediaPlayer mp) {
            mediaPlayer.start();

            int duration = mediaPlayer.getDuration();
            seekBar.setMax(duration);

            timer = new Timer();
            timer.schedule(new TimerTask() {
              @Override
              public void run() {
                int currentPosition = mediaPlayer.getCurrentPosition();
                Message message = Message.obtain();
                message.what = PROGRESS;
                message.obj = currentPosition;
                handler.sendMessage(message);
              }
            },0,1000);
          }
        });

        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
          @Override
          public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
          }

          @Override
          public void onStartTrackingTouch(SeekBar seekBar) {

          }

          @Override
          public void onStopTrackingTouch(SeekBar seekBar) {
            int progress = seekBar.getProgress();
            mediaPlayer.seekTo(progress);
          }
        });
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    
    button.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        String s = editText.getText().toString();
        int y= (int) (Math.random()*300);
        list.add(new DanMu(0,y,s,Color.RED));
      }
    });

    bt_start.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        mediaPlayer.start();
      }
    });

    bt_stop.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        mediaPlayer.pause();
      }
    });
  }

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    if (holder == surfaceHolder) {
      mediaPlayer.setDisplay(holder);
    }else if (holder == surfaceView_danmuHolder) {
      new MyDanMuThread().start();
    }
  }

  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

  }

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {

  }

  class MyDanMuThread extends Thread {
    @Override
    public void run() {
      super.run();
      Paint paint = new Paint();
      paint.setColor(Color.RED);
      paint.setTextSize(40);
      while (true) {
        try {
          Thread.sleep(200);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
        Canvas canvas = surfaceView_danmuHolder.lockCanvas();
        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
        for (int i=0;i<list.size();i  ) {
          DanMu danMu = list.get(i);
          x = danMu.getX();
          danMu.setX(x =10);
          canvas.drawText(danMu.getText(),danMu.getX(),danMu.getY(),paint);
        }
        surfaceView_danmuHolder.unlockCanvasAndPost(canvas);
      }
    }
  }
}

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback{
  SurfaceView surfaceView;
  SurfaceHolder surfaceHolder;
  MediaPlayer mediaPlayer = new MediaPlayer();
  ArrayList<Music> list=new ArrayList<>();
  Timer timer;
  int count = 0;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    surfaceView = findViewById(R.id.sv);

    surfaceHolder=surfaceView.getHolder();
    surfaceHolder.addCallback(this);

    timer = new Timer();
    timer.schedule(new TimerTask() {
      @Override
      public void run() {
        int currentPosition = mediaPlayer.getCurrentPosition();
        if(list.size()>0){
          if(currentPosition>=list.get(count 1).getTime()){
            count  ;
          }
        }

      }
    },0,500);

    try {
      mediaPlayer.setDataSource("/sdcard/凤凰传奇 - 最炫民族风(Live).mp3");
      mediaPlayer.prepareAsync();
      mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
        @Override
        public void onPrepared(MediaPlayer mp) {
          mediaPlayer.start();
        }
      });
    } catch (IOException e) {
      e.printStackTrace();
    }

    try {
      StringBuffer stringBuffer = new StringBuffer();
      FileInputStream fileInputStream = new FileInputStream("/sdcard/最炫民族风");
      byte[] bytes = new byte[1024];
      int len = 0;
      while ((len=fileInputStream.read(bytes))!=-1) {
        stringBuffer.append(new String(bytes,0,len));
      }

      Gson gson = new Gson();
      JavaBean javaBean = gson.fromJson(stringBuffer.toString(), JavaBean.class);
      JavaBean.LrcBean lrc = javaBean.getLrc();
      String lyric = lrc.getLyric();

      String[] split = lyric.split("\n");
      for(int i=0;i<split.length;i  ){
        String trim = split[i].trim();
        String[] split1 = trim.split("]");
        if(split.length>=2){
          String s = split1[0];
          String substring1 = s.substring(1, 3);
          String substring2 = s.substring(4, 6);
          String substring3 = s.substring(7, 10);
          long start = Integer.parseInt(substring1)*60*1000 Integer.parseInt(substring2)*1000 Integer.parseInt(substring3);
          String text = split1[1];
          list.add(new Music(text,start));
        }
      }
    } catch (FileNotFoundException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    new MyThread().start();
  }

  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

  }

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {

  }

  class MyThread extends Thread {
    @Override
    public void run() {
      super.run();
      Paint paint = new Paint();
      paint.setColor(Color.RED);
      paint.setTextSize(50);
      while (true){
        try {
          Thread.sleep(100);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
        Canvas canvas = surfaceHolder.lockCanvas();
        if(canvas==null){
          break;
        }
        canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
        if(list.size()>0){
          canvas.drawText(list.get(count).getTitle(),100,100,paint);
        }
        surfaceHolder.unlockCanvasAndPost(canvas);
      }
    }
  }
}