自定义View类,实现绘制一个随鼠标拖动的矩形。
1、创建一个MySurfaceView类
public class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback, Runnable {
private Paint mPaint;
int widthPixels;
int heightPixels;
float cx, cy;
SurfaceHolder mSurfaceHolder;
Thread thread;
public MeasureView(Context context) {
super(context);
mSurfaceHolder = this.getHolder();
mSurfaceHolder.addCallback(this);
mPaint = new Paint();
thread = new Thread(this);
}
public void draw() {
Canvas canvas = mSurfaceHolder.lockCanvas();
if (mPaint == null || canvas == null) return;
mPaint.setAntiAlias(true);
//用白色清屏
canvas.drawColor(Color.WHITE);
mPai