Round top corners of a UIView and add border

问题:

I have the following code in a category that does rounding of corners. I would also like to draw a border. But the border is not shown on the rounded part of the corner.

Here is the code

- (void) roundTopCorners:(CGFloat) radius
{
    self.layer.masksToBounds = YES;

    CGRect bounds = self.bounds;
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerTopRight) cornerRadii:CGSizeMake(radius, radius)];

    CAShapeLayer *maskLayer = [CAShapeLayer layer];
    maskLayer.frame = bounds;
    maskLayer.path = maskPath.CGPath;
    maskLayer.strokeColor = [UIColor redColor].CGColor;

    self.layer.mask = maskLayer;
}

回答1:

The mask layer doesn't get drawn, just used to compute the mask. Try:

-(void)roundCorners:(UIRectCorner)corners radius:(CGFloat)radius
{
    CGRect bounds = self.bounds;
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:bounds
                                                   byRoundingCorners:corners
                                                         cornerRadii:CGSizeMake(radius, radius)];

    CAShapeLayer *maskLayer = [CAShapeLayer layer];
    maskLayer.frame = bounds;
    maskLayer.path = maskPath.CGPath;

    self.layer.mask = maskLayer;

    CAShapeLayer*   frameLayer = [CAShapeLayer layer];
    frameLayer.frame = bounds;
    frameLayer.path = maskPath.CGPath;
    frameLayer.strokeColor = [UIColor redColor].CGColor;
    frameLayer.fillColor = nil;

    [self.layer addSublayer:frameLayer];
}

-(void)roundTopCornersRadius:(CGFloat)radius
{
    [self roundCorners:(UIRectCornerTopLeft|UIRectCornerTopRight) radius:radius];
}

-(void)roundBottomCornersRadius:(CGFloat)radius
{
    [self roundCorners:(UIRectCornerBottomLeft|UIRectCornerBottomRight) radius:radius];
}

The frame you're currently seeing drawn is the UITextField's normal frame, so set the frame style to none. You'll also have to adjust the insets to make up for the fact that with the frame style set to none there's normally no inset.

回答2:

Swift version of David Berry's answer:

func roundCorners(corners:UIRectCorner, radius:CGFloat) {
    let bounds = self.bounds

    let maskPath = UIBezierPath(roundedRect: bounds, byRoundingCorners: corners, cornerRadii: CGSizeMake(radius, radius))

    let maskLayer = CAShapeLayer()
    maskLayer.frame = bounds
    maskLayer.path = maskPath.CGPath

    self.layer.mask = maskLayer

    let frameLayer = CAShapeLayer()
    frameLayer.frame = bounds
    frameLayer.path = maskPath.CGPath
    frameLayer.strokeColor = UIColor.redColor().CGColor
    frameLayer.fillColor = nil

    self.layer.addSublayer(frameLayer)
}

func roundTopCornersRadius(radius:CGFloat) {
    self.roundCorners([UIRectCorner.TopLeft, UIRectCorner.TopRight], radius:radius)
}

func roundBottomCornersRadius(radius:CGFloat) {
    self.roundCorners([UIRectCorner.BottomLeft, UIRectCorner.BottomRight], radius:radius)
}

回答3:

this is probably a very late answer but I would just like to share the solution I came up with based on answers of different people from different similar questions. I got big help from Vojtech's answer above.

extension UIView {
    func EZRoundCorners(corners:UIRectCorner, radius: CGFloat) -> CAShapeLayer {
        let path = UIBezierPath(roundedRect: self.bounds, byRoundingCorners: corners, cornerRadii: CGSize(width: radius, height: radius))
        let mask = CAShapeLayer()
        mask.path = path.CGPath
        self.layer.mask = mask
        return mask
    }

    func EZRoundCornersWithBorder(corners:UIRectCorner, radius:CGFloat, color:UIColor, width:CGFloat) -> CAShapeLayer {

        let mask = self.EZRoundCorners(corners, radius: radius)

        // Add border
        let borderLayer = EZCALayer()
        borderLayer.path = mask.path // Reuse the Bezier path
        borderLayer.fillColor = UIColor.clearColor().CGColor
        borderLayer.strokeColor = color.CGColor
        borderLayer.lineWidth = width
        borderLayer.frame = self.bounds
        self.layer.addSublayer(borderLayer)
        return borderLayer
    }

    func removeEZLayers () {
        for layer in self.layer.sublayers! {
            if layer is EZCALayer {
                layer.removeFromSuperlayer()
            }
        }
    }
}

class EZCALayer : CAShapeLayer {
}

I inherited from CAShapeLayer so I can remove the border sublayers if I don't want to use them anymore.