Android控件之SurfaceView初步了解

1.SurfaceView 说明：

1）使用了双缓存技术，显示效率非常快，对内存与cpu的开销非常大

A.加载数据 显示界面

B.显示界面 加载数据

2）特点：

a.可以绘制

b.可以在多个多个线程同时修改界面

线程要求：在surfaceCreated时创建，在surfaceDestroyed是销毁

2.绘制：

1）必须获得surface, 通过holder.getSurface();

2）surface.lockCanvas(); 锁定画布

canvas.draw() ;绘制界面

surface.unLockCanvasAndPost();解锁并提交

public class PlantView extends SurfaceView implements SurfaceHolder.Callback{
private boolean isRuning = false;
private SurfaceThread mThread;
private SurfaceHolder mHolder;

public PlantView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}

public PlantView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}

public PlantView(Context context) {
super(context);

mHolder = getHolder();
mHolder.addCallback(this);
}

@Override/**创建是调用*/
public void surfaceCreated(SurfaceHolder holder) {
mThread = new SurfaceThread();
isRuning = true;
mThread.start();
}

@Override/**改变时是调用*/
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// TODO Auto-generated method stub

}

@Override/**销毁时调用*/
public void surfaceDestroyed(SurfaceHolder holder) {
//停止线程
isRuning = false;

}

private class SurfaceThread extends Thread{
@Override
public void run() {
while(isRuning){
try {
drawUI();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

/**
* 绘制矩形
*/
public void drawUI() {
//锁定界面
Canvas canvas = mHolder.lockCanvas();
//画矩形
canvas.drawRect(0, 0, 100, 100, new Paint());
//解锁并提交
mHolder.unlockCanvasAndPost(canvas);
}

}