UIScrollView 不会滚动

Question

我的滚动视图不会滚动。我打开了一张类似的票，并被告知要查看 在 Swift 3 中以编程方式使用 ScrollView，但这并没有回答我的问题，所以我再次打开这张票。有人可以调查一下这个问题并且不要关闭这张票吗？我真的需要帮助。我按照另一张票所说的那样设置了内容大小，但这没有做任何事情。请帮忙！

   let scrollView = UIScrollView()
    scrollView.translatesAutoresizingMaskIntoConstraints = false
    scrollView.showsVerticalScrollIndicator = false
    scrollView.showsHorizontalScrollIndicator = false
    scrollView.bounces = true
    scrollView.alwaysBounceVertical = true
    scrollView.isScrollEnabled = true
    self.view.addSubview(scrollView)
    
       // always a good idea to respect safe area
    let safeG = self.view.safeAreaLayoutGuide
    NSLayoutConstraint.activate([
        scrollView.leadingAnchor.constraint(equalTo: safeG.leadingAnchor),
        scrollView.trailingAnchor.constraint(equalTo: safeG.trailingAnchor),
        scrollView.topAnchor.constraint(equalTo: progressView.bottomAnchor, constant: 20),
        scrollView.bottomAnchor.constraint(equalTo: safeG.bottomAnchor)
    ])
    
    
    // Set the content size of the scrollView
    scrollView.contentSize = CGSize(width: self.view.frame.width, height: CGFloat(4000))
    
    // Create the UILabels, UIImageView, and UIButton
    let titleLabel = UILabel()
    titleLabel.text = "Your Intelligence Types"
    titleLabel.font = UIFont(name: "Inter-Bold", size: 20)
    titleLabel.textAlignment = .center
    
    titleLabel.translatesAutoresizingMaskIntoConstraints = false
    scrollView.addSubview(titleLabel)
    
    // Set constraints for the stackView
    NSLayoutConstraint.activate([
        titleLabel.topAnchor.constraint(equalTo: scrollView.safeAreaLayoutGuide.topAnchor, constant: 20),
        titleLabel.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 20),
        titleLabel.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: -20),
        titleLabel.heightAnchor.constraint(equalToConstant: 30)
    ])
    
    // Create the UILabels, UIImageView, and UIButton
    let descriptionLbl = UILabel()
    descriptionLbl.text = "Different types of intelligence highlight the diverse ways people think, solve problems, and interact with the world around them."
    descriptionLbl.font = UIFont(name: "Inter-Regular", size: 14)
    descriptionLbl.textAlignment = .left
    descriptionLbl.numberOfLines = 0
    
    descriptionLbl.translatesAutoresizingMaskIntoConstraints = false
    scrollView.addSubview(descriptionLbl)
    
    // Set constraints for the stackView
    NSLayoutConstraint.activate([
        descriptionLbl.topAnchor.constraint(equalTo: titleLabel.bottomAnchor, constant: 20),
        descriptionLbl.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 20),
        descriptionLbl.widthAnchor.constraint(equalToConstant: 350),
        descriptionLbl.heightAnchor.constraint(equalToConstant: 60)
    ])
    
    var previousProgressView : UIProgressView? = nil
    let previousTitleHeight: CGFloat = 30
    let progressViewHeight: CGFloat = 20
    let labelHeight: CGFloat = 20
    let verticalSpacing: CGFloat = 20

    var n = 0;
    for (key, value) in totalTypes {
        let typeLabel = UILabel()
        typeLabel.text = key
        typeLabel.font = UIFont(name: "Inter-Bold", size: 16)
        typeLabel.textAlignment = .left
        
        typeLabel.translatesAutoresizingMaskIntoConstraints = false
        
        let iprogressView = UIProgressView(progressViewStyle: .bar)
        iprogressView.trackTintColor = UIColor(red: 0.07, green: 0.45, blue: 0.87, alpha: 0.1)
        iprogressView.tintColor = UIColor(red: 0.07, green: 0.45, blue: 0.87, alpha: 1.00)
        iprogressView.layer.cornerRadius = 4
        iprogressView.clipsToBounds = true
        iprogressView.setProgress(Float(userTypes[key] ?? 0) / Float(value), animated: true)
        iprogressView.translatesAutoresizingMaskIntoConstraints = false
        
        let transform : CGAffineTransform = CGAffineTransform(scaleX: 1.0, y: 3.0)
        iprogressView.transform = transform
        
        let progressLabel = UILabel()
        let progressValue = round(((Float(userTypes[key] ?? 0) / Float(value)) * 100) * 100) / 100
        progressLabel.text = "\(progressValue) %"
        progressLabel.translatesAutoresizingMaskIntoConstraints = false
        progressLabel.font = UIFont(name: "Inter-Regular", size: 16)
        
        scrollView.addSubview(typeLabel)
        scrollView.addSubview(iprogressView)
        scrollView.addSubview(progressLabel)
        
        NSLayoutConstraint.activate([
            typeLabel.topAnchor.constraint(equalTo: previousProgressView?.bottomAnchor ?? descriptionLbl.bottomAnchor, constant: previousProgressView == nil ? verticalSpacing : verticalSpacing),
            typeLabel.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 20),
            typeLabel.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: -20),
            typeLabel.heightAnchor.constraint(equalToConstant: 20),
            
            iprogressView.topAnchor.constraint(equalTo: typeLabel.bottomAnchor, constant: 20),
            iprogressView.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 20),
            iprogressView.widthAnchor.constraint(equalToConstant: 200),
            iprogressView.heightAnchor.constraint(equalToConstant: 3),
            
            // Position the label next to the progressView
            progressLabel.leadingAnchor.constraint(equalTo: iprogressView.trailingAnchor, constant: 10),
            progressLabel.centerYAnchor.constraint(equalTo: iprogressView.centerYAnchor)
        ])
        
        // Update the previousProgressView reference
        previousProgressView = iprogressView
        n += 1
    }

Answer 1

在您的情况下，滚动视图需要来自 safeAreaLayoutGuide 的顶部锚点。

例如

 scrollView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor)