iOS-添加新手操作指引

//先创建一个与主屏幕同样大小的半灰色背景（其实是个长方形）
UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, DZScreenWidth, DZScreenHeight)];

//接着在这个路径下继续加其它路径：椭圆形的路径
[path appendPath:[[UIBezierPath bezierPathWithOvalInRect:maskFrame] bezierPathByReversingPath]];

CAShapeLayer *shapeLayer = [CAShapeLayer layer];

shapeLayer.path = path.CGPath;

[btn.layer setMask:shapeLayer];

//可以将你想加的提示啊什么加上
UIImage *image  = DZImageNameWith(imageStr, @"png");
UIImageView *imgaeView  =  [[UIImageView alloc] initWithImage:image];
imgaeView.centerX = centerX;
imgaeView.y = LabelY;
self.helpImageView = imgaeView;
[btn addSubview:imgaeView];