swift - 根据 titleLabel 的长度调整 UIButton 的大小

问题描述

所以我有一个 UIButton 并且我将其中的标题设置为一个动态长度的字符串。我希望 titleLabel 的宽度是屏幕宽度的一半。我尝试使用 .sizeToFit() 但这会导致按钮在将约束应用于 titleLabel 之前使用 CGSize。我尝试使用 .sizeThatFits(button.titleLabel?.intrinsicContentSize) 但这也没有用。我认为下面的重要函数是 init() 和 presentCallout()，但我展示整个类只是为了更完整地理解。我正在玩的课程看起来像：

class CustomCalloutView: UIView, MGLCalloutView {
    var representedObject: MGLAnnotation
    
    // Allow the callout to remain open during panning.
    let dismissesAutomatically: Bool = false
    let isAnchoredToAnnotation: Bool = true
    
    // https://github.com/mapbox/mapbox-gl-native/issues/9228
    override var center: CGPoint {
        set {
            var newCenter = newValue
            newCenter.y -= bounds.midY
            super.center = newCenter
        }
        get {
            return super.center
        }
    }
    
    lazy var leftAccessoryView = UIView() /* unused */
    lazy var rightAccessoryView = UIView() /* unused */
    
    weak var delegate: MGLCalloutViewDelegate?
    
    let tipHeight: CGFloat = 10.0
    let tipWidth: CGFloat = 20.0
    
    let mainBody: UIButton
    
    required init(representedObject: MGLAnnotation) {
        self.representedObject = representedObject
        self.mainBody = UIButton(type: .system)
        
        super.init(frame: .zero)
        
        backgroundColor = .clear
        
        mainBody.backgroundColor = .white
        mainBody.tintColor = .black
        mainBody.contentEdgeInsets = UIEdgeInsets(top: 10.0, left: 10.0, bottom: 10.0, right: 10.0)
        mainBody.layer.cornerRadius = 4.0
        
        addSubview(mainBody)
//        I thought this would work, but it doesn't.
//        mainBody.translatesAutoresizingMaskIntoConstraints = false
//        mainBody.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
//        mainBody.leftAnchor.constraint(equalTo: self.rightAnchor).isActive = true
//        mainBody.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
//        mainBody.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
    }
    
    required init?(coder decoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - MGLCalloutView API
    func presentCallout(from rect: CGRect, in view: UIView, constrainedTo constrainedRect: CGRect, animated: Bool) {
        
        delegate?.calloutViewWillAppear?(self)
        view.addSubview(self)
        
        // Prepare title label.
        mainBody.setTitle(representedObject.title!, for: .normal)
        mainBody.titleLabel?.lineBreakMode = .byWordWrapping
        mainBody.titleLabel?.numberOfLines = 0
        mainBody.sizeToFit()
        
        if isCalloutTappable() {
            // Handle taps and eventually try to send them to the delegate (usually the map view).
            mainBody.addTarget(self, action: #selector(CustomCalloutView.calloutTapped), for: .touchUpInside)
        } else {
            // Disable tapping and highlighting.
            mainBody.isUserInteractionEnabled = false
        }
        
        // Prepare our frame, adding extra space at the bottom for the tip.
        let frameWidth = mainBody.bounds.size.width
        let frameHeight = mainBody.bounds.size.height + tipHeight
        let frameOriginX = rect.origin.x + (rect.size.width/2.0) - (frameWidth/2.0)
        let frameOriginY = rect.origin.y - frameHeight
        frame = CGRect(x: frameOriginX, y: frameOriginY, width: frameWidth, height: frameHeight)
        
        if animated {
            alpha = 0
            
            UIView.animate(withDuration: 0.2) { [weak self] in
                guard let strongSelf = self else {
                    return
                }
                
                strongSelf.alpha = 1
                strongSelf.delegate?.calloutViewDidAppear?(strongSelf)
            }
        } else {
            delegate?.calloutViewDidAppear?(self)
        }
    }
    
    func dismissCallout(animated: Bool) {
        if (superview != nil) {
            if animated {
                UIView.animate(withDuration: 0.2, animations: { [weak self] in
                    self?.alpha = 0
                }, completion: { [weak self] _ in
                    self?.removeFromSuperview()
                })
            } else {
                removeFromSuperview()
            }
        }
    }
    
    // MARK: - Callout interaction handlers
    
    func isCalloutTappable() -> Bool {
        if let delegate = delegate {
            if delegate.responds(to: #selector(MGLCalloutViewDelegate.calloutViewShouldHighlight)) {
                return delegate.calloutViewShouldHighlight!(self)
            }
        }
        return false
    }
    
    @objc func calloutTapped() {
        if isCalloutTappable() && delegate!.responds(to: #selector(MGLCalloutViewDelegate.calloutViewTapped)) {
            delegate!.calloutViewTapped!(self)
        }
    }
    
    // MARK: - Custom view styling
    
    override func draw(_ rect: CGRect) {
        // Draw the pointed tip at the bottom.
        let fillColor: UIColor = .white
        
        let tipLeft = rect.origin.x + (rect.size.width / 2.0) - (tipWidth / 2.0)
        let tipBottom = CGPoint(x: rect.origin.x + (rect.size.width / 2.0), y: rect.origin.y + rect.size.height)
        let heightWithoutTip = rect.size.height - tipHeight - 1
        
        let currentContext = UIGraphicsGetCurrentContext()!
        
        let tipPath = CGMutablePath()
        tipPath.move(to: CGPoint(x: tipLeft, y: heightWithoutTip))
        tipPath.addLine(to: CGPoint(x: tipBottom.x, y: tipBottom.y))
        tipPath.addLine(to: CGPoint(x: tipLeft + tipWidth, y: heightWithoutTip))
        tipPath.closeSubpath()
        
        fillColor.setFill()
        currentContext.addPath(tipPath)
        currentContext.fillPath()
    }
}

这就是短标题和长标题的样子。当标题变得太长时，我希望文本换行并且气泡获得更高的高度。正如您在下面的图片集中看到的那样，第一个“短名称”可以作为地图注释气泡正常工作。但是，当名称变得超长时，它只会将气泡扩大到离开屏幕的程度。

https://imgur.com/a/I5z0zUd

非常感谢任何有关如何修复的帮助。谢谢！

标签： swiftxcodeuibuttonuilabelnslayoutconstraint

swift - 根据 titleLabel 的长度调整 UIButton 的大小

问题描述

解决方案

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