创建Canvas的方式
Bitmap bitmap = Bitmap.createBitmap(500, 500, Bitmap.Config.ARGB_8888);
Canvas canvas1 = new Canvas();
Canvas canvas2 = new Canvas(bitmap);
//使用于绘制高质量图形,刷新频率高,但是系统花销比较大
SurfaceView surfaceView = new SurfaceView(context);
SurfaceHolder holder = surfaceView.getHolder();
Canvas canvas = holder.lockCanvas();
holder.unlockCanvasAndPost(canvas);