扣丁学堂——SurfaceView(实现画图 播放视频)

/**
 * 自定义 surfaceView（相当于独立的一块屏幕）
 */
public class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback {
    //控制屏幕绘制的对象
    private SurfaceHolder holder;
    private MyThread thread;

    public MySurfaceView(Context context) {
        super(context);
        holder = this.getHolder();
        //添加回调接口，因为实现了，所以传this，对象一创建就调用回调的方法
        holder.addCallback(this);
    }

    class MyThread implements Runnable {
        private SurfaceHolder holder;
        //作用：线程什么进侯开始，什么时侯结束
        public boolean isRun;

        public MyThread(SurfaceHolder holder) {
            this.holder = holder;
            isRun = true;
        }

        @Override
        public void run() {
            int count = 0;
            Canvas canvas = null;
            while (isRun) {
                try {
                    synchronized (holder) {
                        //因为有多个 线程在操作，所以要同步
                        //锁定一个画布,锁定后，可以通过其返回的 画布对象 Canvas，在上面画图等操作了
                        canvas = holder.lockCanvas();
                        canvas.drawColor(Color.BLACK);
                        Paint p = new Paint();
                        p.setColor(Color.RED);
                        p.setStyle(Paint.Style.FILL);
                        p.setAntiAlias(true);
                        canvas.drawRect(10, 10, 100, 100, p);
                        p.setTextSize(30);
                        canvas.drawText("当前是第 " + (count++)+" 秒", 10, 150, p);

                        Thread.sleep(1000);
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    holder.unlockCanvasAndPost(canvas);//释放 画布的锁
                }
            }
        }
    }
    /*************** 事件回调方法  *********************************/
    /**
     * 回调
     *
     * @param holder
     */
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        thread = new MyThread(holder);
        thread.isRun = true;
        new Thread(thread).start();
    }

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

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        thread.isRun = false;
    }
}

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
//        setContentView(new MyView(this));
//        setContentView(new MyImageView(this));
        setContentView(new MySurfaceView(this));
    }
}

public class VideoActivity extends AppCompatActivity implements SurfaceHolder.Callback{

    private SurfaceView surfaceView;
    private SurfaceHolder holder;
    private MediaPlayer mp;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_video);
        surfaceView = (SurfaceView) findViewById(R.id.surfaceView);
        holder = surfaceView.getHolder();
        holder.addCallback(this);
        holder.setFixedSize(320,220);
    }

    public void playClick(View view) {
        mp.start();
    }

    public void pauseClick(View view) {
        mp.pause();
    }

    public void stopClick(View view) {
        mp.stop();
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        mp = new MediaPlayer();
        mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mp.setDisplay(holder);
        String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES)+"/2.mp4";
        try {
            mp.setDataSource(path);//设置播放视频源
            mp.prepare();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

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

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        if (mp!=null){
            if (mp.isPlaying()){
                mp.stop();
                mp.release();
            }
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mp!=null){
            if (mp.isPlaying()){
                mp.stop();
                mp.release();
            }
        }
    }
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.codingke.vince59_canvas_drawable.VideoActivity">

    <SurfaceView
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:id="@+id/surfaceView"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="播放"
        android:onClick="playClick"
        android:id="@+id/button"
        android:layout_alignTop="@+id/button3"
        android:layout_toLeftOf="@+id/button2"
        android:layout_toStartOf="@+id/button2" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="暂停"
        android:onClick="pauseClick"
        android:id="@+id/button2"
        android:layout_alignTop="@+id/button"
        android:layout_centerHorizontal="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="停止"
        android:onClick="stopClick"
        android:id="@+id/button3"
        android:layout_below="@+id/surfaceView"
        android:layout_toRightOf="@+id/button2"
        android:layout_toEndOf="@+id/button2" />
</RelativeLayout>