SurfaceView 试用

Posted 2022-11-21 小威少威

由于项目需要用到动画效果，如果大量绘制animation，则性能不佳，上网搜了，有surfaceview这个东西（不占用主线程）。因此自己学习了一下，以下demo是实现每个一秒钟绘制显示不同颜色的笑脸。
涉及点：SurfaceView、SurfaceHolder。

一、实现效果：

二、自定义surfaceview类
1、：
继承SurfaceView,实现SurfaceHolder Callback接口。

2、重写构造方法

3、实现三个callback方法：

 @Override
    public void surfaceCreated(SurfaceHolder holder) 
    

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

    

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) 
    

三、整体代码：

public class MySurfaceViewTest extends SurfaceView implements SurfaceHolder.Callback

    private SurfaceHolder mSurfaceHolder;
    private MyThread mMyThread;
    private boolean isDraw = false;

    public MySurfaceViewTest(Context context) 
        super(context);
        mSurfaceHolder = this.getHolder();
        mSurfaceHolder.addCallback(this);
        mMyThread = new MyThread();
    

    private class MyThread extends Thread 
        @Override
        public void run() 
            while (isDraw) 
                try 
                    sleep(1000);//睡一秒钟
                    drawUI();
                 catch (Exception e) 

                
            
            super.run();

        
    

    private void drawUI() 

        Canvas canvas = null;
        try 
            canvas = mSurfaceHolder.lockCanvas();
            synchronized (mSurfaceHolder) 
                drawCanvas(canvas);
            
         finally 
            if (canvas != null) 
                mSurfaceHolder.unlockCanvasAndPost(canvas);
            
        
    

    private void drawCanvas(Canvas canvas) 
        // 在 canvas 上绘制需要的图形
        if (canvas != null) 
            Log.d("weiwei","come-----------------------------------------------");
            canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR); // 清空界面

            Paint p = new Paint();
            p.setColor(CircleTextImageUtil.getRandomColor());// 设置随机颜色
//            //画笑脸弧线
            p.setStyle(Paint.Style.STROKE);//设置空心
            RectF oval1=new RectF(150,20,180,40);
            canvas.drawArc(oval1, 180, 180, false, p);//小弧形
            oval1.set(190, 20, 220, 40);
            canvas.drawArc(oval1, 180, 180, false, p);//小弧形
            oval1.set(160, 30, 210, 60);
            canvas.drawArc(oval1, 0, 180, false, p);//小弧形
        
    


    static class  CircleTextImageUtil 
        /**
         * Get the random color.
         *
         * @return
         */
        private static int getRandomColor() 
            List<Integer> colorList = new ArrayList<Integer>();
            colorList.add(Color.RED);
            colorList.add(Color.BLUE);
            colorList.add(Color.GREEN);
            colorList.add(Color.WHITE);
            colorList.add(Color.YELLOW);
            colorList.add(Color.GRAY);
            return colorList.get((int) (Math.random() * colorList.size()));
        

    

    @Override
    public void surfaceCreated(SurfaceHolder holder) 
        isDraw = true;
        mMyThread.start();
    

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

    

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) 
        isDraw = false;
    

引用：

public class MainActivity extends AppCompatActivity 

    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        CrashReport.initCrashReport(getApplicationContext(), "077d3ebb59", false);
        MySurfaceViewTest mySurfaceViewTest = new MySurfaceViewTest(this);
//        setContentView(R.layout.activity_main);
        setContentView(mySurfaceViewTest);