给UIView指定角设置圆角

通过UIRectCorner和 UIBezierPath组合给进行设置

// cornerRadius圆角大小，cornerRadius指定角
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:corners cornerRadii:CGSizeMake(cornerRadius, cornerRadius)];
    maskLayer.maskLayer.frame = self.bounds;
    maskLayer.path = maskPath.CGPath;
    self.layer.mask = maskLayer;

Demo