Andrio studio 学习 之视频弹幕

效果

xml布局

<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="com.example.ytx0904.myapplication.MainActivity">
<!--第一个显示弹幕的-->
<SurfaceView
android:id="@+id/surface_text"
android:layout_width="match_parent"
android:layout_height="200dp" />
<!--第二个播放视频-->
<SurfaceView
android:id="@+id/surface_media"
android:layout_width="match_parent"
android:layout_height="200dp" />
</FrameLayout>

activity代码

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.io.IOException;

import javax.security.auth.login.LoginException;

public class MainActivity  extends AppCompatActivity implements SurfaceHolder.Callback {
private MediaPlayer mediaPlayer;//播放视频和音频
private SurfaceView surfaceView,surfaceView2;//UI控件，显示画面
private SurfaceHolder surfaceHolder,surfaceHolder2;//不能直接操作surfaceView，但是可以通过surfaceHolder来操作surfaceView
int x=20;//文字的初始位置
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//TODO 1:搞mediaPalyer
try {
initPlayer();
} catch (IOException e) {
e.printStackTrace();
}
//TODO 2:搞surfaceView ，在surfaceview create生命周期的时候二者绑定
initView();
}

//初始化surfaceView
private void initView() {

//播放视频的
surfaceView=findViewById(R.id.surface_view);
surfaceHolder=surfaceView.getHolder();
surfaceHolder.addCallback(this);//设置回调监听：获得surfaceView的生命周期
//显示弹幕的，需要将surfaceView2设置为透明
surfaceView2=findViewById(R.id.surface_view2);
surfaceHolder2=surfaceView2.getHolder();
surfaceHolder2.addCallback(this);
//TODO ：设置surfaceView2透明
surfaceView2.setZOrderOnTop(true);
surfaceHolder2.setFormat(PixelFormat.TRANSLUCENT);

}

//初始化player对象
private void initPlayer() throws IOException {
if(mediaPlayer==null){
mediaPlayer=new MediaPlayer();
}
mediaPlayer.reset();
mediaPlayer.setDataSource("http://uvideo.spriteapp.cn/video/2019/0512/56488d0a-7465-11e9-b91b-1866daeb0df1_wpd.mp4");
mediaPlayer.prepare();
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {//准备完毕了

mediaPlayer.start();
}
});
}

//创建完成
@Override
public void surfaceCreated(SurfaceHolder holder) {
if(holder==surfaceHolder){ //将holder和player二者结合在一起
mediaPlayer.setDisplay(surfaceHolder);
}else if(holder==surfaceHolder2){//显示弹幕
new Thread(){
@Override
public void run() {
super.run();
while (true){
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
//画笔
Paint paint = new Paint();
paint.setStrokeWidth(5);
paint.setColor(Color.GREEN);
paint.setTextSize(30);//设置文字的大小

Canvas canvas = surfaceHolder2.lockCanvas();
if(canvas==null){
break;}
//TODO ：这里不将画布刷白，刷透明
canvas.drawColor(PixelFormat.TRANSPARENT, PorterDuff.Mode.CLEAR);
canvas.drawText("猴子成精了",x+=20,50,paint);
surfaceHolder2.unlockCanvasAndPost(canvas);
}

}
}.start();
}

}
//改变了
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

}
//销毁了
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
//释放mediaplayer的资源
mediaPlayer.release();//释放资源
mediaPlayer=null;//回收掉

}
}