SurfaceView简单用法

来源：互联网发布：淘宝app首页怎么实现编辑：程序博客网时间：2024/06/06 00:37

快速学会SurfaceView用法：

SurfaceView是视图(View)的继承类，这个视图里内嵌了一个专门用于绘制的Surface。你可以控制这个Surface的格式和尺寸。Surfaceview控制这个Surface的绘制位置。
第一步：

继承SurfaceView并实现SurfaceHolder.Callback接口

第二步： SurfaceView.getHolder()获得SurfaceHolder对象

第三步：SurfaceHolder.addCallback(callback)添加回调函数

第四步：SurfaceHolder.lockCanvas()获得Canvas对象并锁定画布

第五步：Canvas绘画

第六步：SurfaceHolder.unlockCanvasAndPost(Canvas canvas)结束锁定画图，并提交改变，将图形显示。

首先测试代码：

public class MySurfaceViewTestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MySurfaceView(this));
    }
}

然后创建MySurfaceView类

public class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback{
private Canvas canvas;
SurfaceHolder myholder;
public MySurfaceView(Context context) {
  super(context);
  System.out.println("构造方法");
  //获取SurfaceHolder对象
  myholder=getHolder();
  //添加回调函数，绑定回调方法
  myholder.addCallback(this);
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
System.out.println("surfaceChanged方法");
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
  System.out.println("surfaceCreated方法");
  //锁定画布
  canvas=myholder.lockCanvas();

  //设置画笔
  Paint paint=new Paint();
  paint.setColor(Color.RED);
  //绘制图形
  canvas.drawLine(10, 20, 40, 40, paint);
  canvas.drawCircle(50, 50, 6, paint);
  myholder.unlockCanvasAndPost(canvas);
  Rect rect=new Rect(70, 70, 200, 200);
  Canvas mycanvas=myholder.lockCanvas(rect);
  paint.setColor(Color.GREEN);
  //绘制图形

  mycanvas.drawCircle(75, 75, 5, paint);
  myholder.unlockCanvasAndPost(mycanvas);
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
  System.out.println("surfaceDestroyed方法");
  //销毁时激发，一般在这里将画图的线程停止、释放。
  myholder.unlockCanvasAndPost(canvas);

}
}

运行结果如下：

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