自定义 iOS UIButton 子类未更新标题

Question

I have a subclass of a UIButton that takes the title label, and puts it under the button's image, as opposed to the right of the image:

final class ImageButton: UIButton {
    @IBInspectable var cornerRadius: CGFloat = 8
    @IBInspectable var borderColor: UIColor? = .black
    
    private enum Constants {
        static let imageSize: CGFloat = 40
        static let titleHeight: CGFloat = 12
    }
    
    override func titleRect(forContentRect contentRect: CGRect) -> CGRect {
        if #available(iOS 15, *) {
            return super.titleRect(forContentRect: contentRect)
        }
        else {
            _ = super.titleRect(forContentRect: contentRect)
            return CGRect(
                x: 0,
                y: contentRect.height - Constants.titleHeight,
                width: contentRect.width,
                height: Constants.titleHeight
            )
        }
    }
    
    override func imageRect(forContentRect contentRect: CGRect) -> CGRect {
        if #available(iOS 15, *) {
            return super.imageRect(forContentRect: contentRect)
        } else {
            return CGRect(
                x: contentRect.width / 2 - Constants.imageSize / 2,
                y: (contentRect.height - titleRect(forContentRect: contentRect).height) / 2 - Constants.imageSize / 2,
                width: Constants.imageSize,
                height: Constants.imageSize
            )
        }
    }
    
    override var intrinsicContentSize: CGSize {
        
        if #available(iOS 15, *) {
            return super.intrinsicContentSize
        }
        else {
            _ = super.intrinsicContentSize
            let size = titleLabel?.sizeThatFits(contentRect(forBounds: bounds).size) ?? .zero
            let spacing: CGFloat = 12
            return CGSize(
                width: max(size.width, Constants.imageSize),
                height: Constants.imageSize + Constants.titleHeight + spacing
            )
        }
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }
    
    private func setup() {
        if #available(iOS 15, *) {
            var myConfiguration = UIButton.Configuration.plain()
            myConfiguration.imagePlacement = .top
            self.configuration = myConfiguration
        } else {
            titleLabel?.textAlignment = .center
        }
    }
    override func draw(_ rect: CGRect) {
        layer.cornerRadius = cornerRadius
        layer.masksToBounds = true
        layer.borderWidth = 1
        layer.borderColor = borderColor?.cgColor
    }
}

Trying to change the button's title does not have any effect:

myCustomButton.setTitle("Disable Box Select", for: .normal)

I tried adding:

myCustomButton.layer.setNeedsLayout() myCustomButton.layer.setNeedsDisplay()

But, nothing seems to change the title of myCustomButton

Answer 1

This is not really an answer, but in response to the OP's comment...

Storyboard:

Complete controller code (using your posted ImageButton class, unedited):

class CustBtnVC: UIViewController {

    @IBOutlet var myCustomButton: ImageButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        if #available(iOS 15.0, *) {
            var cfg = myCustomButton.configuration
            cfg?.title = "Test"
            myCustomButton.configuration = cfg
        } else {
            // Fallback on earlier versions
            myCustomButton.setTitle("Pre-15 Test", for: .normal)
        }
    }
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if #available(iOS 15.0, *) {
            var cfg = myCustomButton.configuration
            cfg?.title = "Disable Box Select"
            myCustomButton.configuration = cfg
        } else {
            // Fallback on earlier versions
            myCustomButton.setTitle("Pre-15 Disable Box Select", for: .normal)
        }
    }
    
}

Note: since your custom button code is setting the button style for iOS 15+ the button .configuration should be used instead of .setTitle(...) when running on iOS 15+

On launch:

after tap on the view: