How to add a border just on the top side of a UIVi

Question

My question is on the title.

I don't know how to add a border in a specific side, top or bottom, any side... layer.border draws the border for the whole view...

Answer 1

I consider subclassing UIView and overriding drawRect overkill here. Why not add an extension on UIView and add border subviews?

@discardableResult
func addBorders(edges: UIRectEdge,
                color: UIColor,
                inset: CGFloat = 0.0,
                thickness: CGFloat = 1.0) -> [UIView] {

    var borders = [UIView]()

    @discardableResult
    func addBorder(formats: String...) -> UIView {
        let border = UIView(frame: .zero)
        border.backgroundColor = color
        border.translatesAutoresizingMaskIntoConstraints = false
        addSubview(border)
        addConstraints(formats.flatMap {
            NSLayoutConstraint.constraints(withVisualFormat: $0,
                                           options: [],
                                           metrics: ["inset": inset, "thickness": thickness],
                                           views: ["border": border]) })
        borders.append(border)
        return border
    }


    if edges.contains(.top) || edges.contains(.all) {
        addBorder(formats: "V:|-0-[border(==thickness)]", "H:|-inset-[border]-inset-|")
    }

    if edges.contains(.bottom) || edges.contains(.all) {
        addBorder(formats: "V:[border(==thickness)]-0-|", "H:|-inset-[border]-inset-|")
    }

    if edges.contains(.left) || edges.contains(.all) {
        addBorder(formats: "V:|-inset-[border]-inset-|", "H:|-0-[border(==thickness)]")
    }

    if edges.contains(.right) || edges.contains(.all) {
        addBorder(formats: "V:|-inset-[border]-inset-|", "H:[border(==thickness)]-0-|")
    }

    return borders
}

    // Usage:         
    view.addBorder(edges: [.all]) // All with default arguments 
    view.addBorder(edges: [.top], color: .green) // Just Top, green, default thickness
    view.addBorder(edges: [.left, .right, .bottom], color: .red, thickness: 3) // All except Top, red, thickness 3

With this code you're not tied to your subclass too, you can apply it to anything and everything that inherits from UIView - reusable in your project, and any others. Pass in other arguments to your methods to define other colours and widths. Many options.

Answer 2

For me works

extension UIView {

    func addBorders(edges: UIRectEdge = .all, color: UIColor = .black, width: CGFloat = 1.0) {

        func createBorder() -> UIView {
            let borderView = UIView(frame: CGRect.zero)
            borderView.translatesAutoresizingMaskIntoConstraints = false
            borderView.backgroundColor = color
            return borderView
        }

        if (edges.contains(.all) || edges.contains(.top)) {
            let topBorder = createBorder()
            self.addSubview(topBorder)
            NSLayoutConstraint.activate([
                topBorder.topAnchor.constraint(equalTo: self.topAnchor),
                topBorder.leadingAnchor.constraint(equalTo: self.leadingAnchor),
                topBorder.trailingAnchor.constraint(equalTo: self.trailingAnchor),
                topBorder.heightAnchor.constraint(equalToConstant: width)
                ])
        }
        if (edges.contains(.all) || edges.contains(.left)) {
            let leftBorder = createBorder()
            self.addSubview(leftBorder)
            NSLayoutConstraint.activate([
                leftBorder.topAnchor.constraint(equalTo: self.topAnchor),
                leftBorder.bottomAnchor.constraint(equalTo: self.bottomAnchor),
                leftBorder.leadingAnchor.constraint(equalTo: self.leadingAnchor),
                leftBorder.widthAnchor.constraint(equalToConstant: width)
                ])
        }
        if (edges.contains(.all) || edges.contains(.right)) {
            let rightBorder = createBorder()
            self.addSubview(rightBorder)
            NSLayoutConstraint.activate([
                rightBorder.topAnchor.constraint(equalTo: self.topAnchor),
                rightBorder.bottomAnchor.constraint(equalTo: self.bottomAnchor),
                rightBorder.trailingAnchor.constraint(equalTo: self.trailingAnchor),
                rightBorder.widthAnchor.constraint(equalToConstant: width)
                ])
        }
        if (edges.contains(.all) || edges.contains(.bottom)) {
            let bottomBorder = createBorder()
            self.addSubview(bottomBorder)
            NSLayoutConstraint.activate([
                bottomBorder.bottomAnchor.constraint(equalTo: self.bottomAnchor),
                bottomBorder.leadingAnchor.constraint(equalTo: self.leadingAnchor),
                bottomBorder.trailingAnchor.constraint(equalTo: self.trailingAnchor),
                bottomBorder.heightAnchor.constraint(equalToConstant: width)
                ])
        }
    }
}

Answer 3

Swift version of Adam Waite's awesome 5/5/15 addition:

extension CALayer {

  func addBorder(edge: UIRectEdge, color: UIColor, thickness: CGFloat) {

    var border = CALayer()

    switch edge {
    case .Top:
        border.frame = CGRectMake(0, 0, CGRectGetWidth(self.frame), thickness)
        break
    case .Bottom:
        border.frame = CGRectMake(0, CGRectGetHeight(self.frame) - thickness, CGRectGetWidth(self.frame), thickness)
        break
    case .Left:
        border.frame = CGRectMake(0, 0, thickness, CGRectGetHeight(self.frame))
        break
    case .Right:
        border.frame = CGRectMake(CGRectGetWidth(self.frame) - thickness, 0, thickness, CGRectGetHeight(self.frame))
        break
    default:
        break
    }

    border.backgroundColor = color.CGColor;

    addSublayer(border)
  }
}

Swift 3:

extension CALayer {

    func addBorder(edge: UIRectEdge, color: UIColor, thickness: CGFloat) {

        let border = CALayer()

        switch edge {
        case .top:
            border.frame = CGRect(x: 0, y: 0, width: frame.width, height: thickness)
        case .bottom:
            border.frame = CGRect(x: 0, y: frame.height - thickness, width: frame.width, height: thickness)
        case .left:
            border.frame = CGRect(x: 0, y: 0, width: thickness, height: frame.height)
        case .right:
            border.frame = CGRect(x: frame.width - thickness, y: 0, width: thickness, height: frame.height)
        default:
            break
        }

        border.backgroundColor = color.cgColor;

        addSublayer(border)
    }
}

Answer 4

The best way for me is a category on UIView, but adding views instead of CALayers, so we can take advantage of AutoresizingMasks to make sure borders resize along with the superview.

- (void)addTopBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    [border setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleBottomMargin];
    border.frame = CGRectMake(0, 0, self.frame.size.width, borderWidth);
    [self addSubview:border];
}

- (void)addBottomBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    [border setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleTopMargin];
    border.frame = CGRectMake(0, self.frame.size.height - borderWidth, self.frame.size.width, borderWidth);
    [self addSubview:border];
}

- (void)addLeftBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    border.frame = CGRectMake(0, 0, borderWidth, self.frame.size.height);
    [border setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleRightMargin];
    [self addSubview:border];
}

- (void)addRightBorderWithColor:(UIColor *)color andWidth:(CGFloat) borderWidth {
    UIView *border = [UIView new];
    border.backgroundColor = color;
    [border setAutoresizingMask:UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin];
    border.frame = CGRectMake(self.frame.size.width - borderWidth, 0, borderWidth, self.frame.size.height);
    [self addSubview:border];
}

Answer 5

Code for the selected answer, in case anyone wants it.

NOTE: This does not work with autolayout (aka, rotating device to landscape, etc).

First define a thickness:

NSInteger borderThickness = 1;

Then just copy use any or all of these to set the border you want to set.

Top Border

UIView *topBorder = [UIView new];
topBorder.backgroundColor = [UIColor lightGrayColor];
topBorder.frame = CGRectMake(0, 0, myView.frame.size.width, borderThickness);
[myView addSubview:topBorder];

Bottom Border

UIView *bottomBorder = [UIView new];
bottomBorder.backgroundColor = [UIColor lightGrayColor];
bottomBorder.frame = CGRectMake(0, myView.frame.size.height - borderThickness, myView.frame.size.width, borderThickness);
[myView addSubview:bottomBorder];

Left Border

UIView *leftBorder = [UIView new];
leftBorder.backgroundColor = [UIColor lightGrayColor];
leftBorder.frame = CGRectMake(0, 0, borderThickness, myView.frame.size.height);
[myView addSubview:leftBorder];

Right Border

UIView *rightBorder = [UIView new];
rightBorder.backgroundColor = [UIColor lightGrayColor];
rightBorder.frame = CGRectMake(myView.frame.size.width - borderThickness, 0, borderThickness, myView.frame.size.height);
[myView addSubview:rightBorder];

Answer 6

Here's a simple solution. Add a label onto your UIView, clear the text on the label and set the label background color to be your border color. Set the origin (x,y) of your label to be the origin (x,y) of your view. and set the width of the label to be the width of your UIView, set the height to be 1 or 2 (for your border height at the top of your UIView). And that should do the trick.