ios view设置圆角

///全角设置
 UIView *yview = [[UIView alloc] initWithFrame:frame(10, 10, 100, 200)];
        yview.backgroundColor = [UIColor whiteColor];
        yview.layer.cornerRadius = 3;
        yview.layer.masksToBounds = YES;
        [self addSubview: yview];
        
///半角设置
        UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect: yview.bounds byRoundingCorners:UIRectCornerBottomLeft | UIRectCornerBottomRight cornerRadii:CGSizeMake(10, 10)];
        CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
        maskLayer.frame = yview.bounds;
        maskLayer.path = maskPath.CGPath;
        yview.layer.mask = maskLayer;

///设置弧度角
* UIRectCornerTopLeft
* UIRectCornerTopRight
* UIRectCornerBottomLeft
* UIRectCornerBottomRight
* UIRectCornerAllCorners