<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  tools:context=".DanmuActivity">

  <SurfaceView
    android:id="@+id/sv_text"
    android:layout_width="match_parent"
    android:layout_height="400dp"/>

  <SurfaceView
    android:id="@+id/sv_media"
    android:layout_width="match_parent"
    android:layout_height="400dp"/>
    />


  <EditText
    android:id="@+id/et_text"
    android:layout_width="300dp"
    android:layout_height="wrap_content"
    android:layout_marginTop="450dp"/>

  <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="發(fā)送"
    android:layout_marginTop="500dp"
    android:onClick="Gogo"/>
</FrameLayout>

public class Danmu {

  String text;//彈幕內(nèi)容
  int x;//x軸
  int y;//y軸

  public Danmu(String text){
    this.text = text;
    //將y設(shè)置為隨機(jī),彈幕出現(xiàn)的位置也為隨機(jī)
    this.y = (int) (Math.random()*400);
    this.x = 0;
  }
}

//視頻播放
private MediaPlayer mediaPlayer;
//彈幕Surface與視頻Surface
private SurfaceView sv_text, sv_media;
//兩個Surface對應(yīng)的兩個holder
private SurfaceHolder text_holder, media_holder;
EditText editText;//字幕輸入框
List<Danmu> list = new ArrayList<>();//存放

private void initPlayer() throws IOException {
 //先判斷是否創(chuàng)建過,沒創(chuàng)建就創(chuàng)建出來
    if (mediaPlayer == null) {
      mediaPlayer = new MediaPlayer();
    }
    mediaPlayer.reset();//使其恢復(fù)空閑狀態(tài)
    //播放的資源
    mediaPlayer.setDataSource("http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4");
    mediaPlayer.prepare();//準(zhǔn)備
    mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
      @Override
      public void onPrepared(MediaPlayer mp) {//準(zhǔn)備完畢了
        mediaPlayer.start();//播放
      }
    });
  }

private void initView() {

    sv_text = findViewById(R.id.sv_text);
    text_holder = sv_text.getHolder();
    text_holder.addCallback(this);

    sv_media = findViewById(R.id.sv_media);
    media_holder = sv_media.getHolder();
    media_holder.addCallback(this);

    editText = findViewById(R.id.et_text);

    //設(shè)置透明,將播放彈幕的Surface放到第一位并設(shè)置為背景透明
    sv_text.setZOrderOnTop(true);
    text_holder.setFormat(PixelFormat.TRANSPARENT);
  }

@Override
  public void surfaceCreated(SurfaceHolder holder) {
  //判斷當(dāng)前holder是否是media的那個
    if (holder == media_holder) {
    //設(shè)置要顯示的Surfaceholder
      mediaPlayer.setDisplay(media_holder);
        //判斷當(dāng)前holder是否是字幕的那個
    } else if (holder == text_holder) {
    //創(chuàng)建線程執(zhí)行耗時操作
      new Thread() {
        @Override
        public void run() {
          super.run();
          //死循環(huán)用來一直更新彈幕的位置
          while (true) {
            try {
              Thread.sleep(500);
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
  Paint paint = new Paint();//創(chuàng)建畫筆
 paint.setStrokeWidth(5);//畫筆粗細(xì)
 paint.setColor(Color.GREEN);//畫筆顏色
  paint.setTextSize(30);//設(shè)置文字大小
 //創(chuàng)建畫板
   Canvas canvas = text_holder.lockCanvas();
   //判斷若畫板為空則跳出循環(huán)
            if (canvas == null) {
              break;
            }
        //設(shè)置畫布顏色,透明
 canvas.drawColor(PixelFormat.TRANSPARENT, PorterDuff.Mode.CLEAR);
 //用循環(huán)來你的彈幕集合并且在畫板上展示出來
 //x+=20為你的彈幕在不斷的從左到右移動
      for (Danmu danmu : list) {
  canvas.drawText(danmu.text, danmu.x += 20, danmu.y, paint);
  //若移動的位置大于視頻Surface的寬度了就歸0
     if (danmu.x > sv_media.getWidth()) {
                danmu.x = 0;
           }
          }
          //將畫布解鎖并顯示到屏幕上
    text_holder.unlockCanvasAndPost(canvas);
          }
        }
      }.start();//不要忘記開啟線程

    }

  }

public void Gogo(View view) {
//先判斷輸入框里有沒有東西
    if (!editText.getText().toString().isEmpty() && !editText.getText().toString().equals("")) {
      Danmu danmu = new Danmu(editText.getText().toString());
      list.add(danmu);
    }
  }