无法在 swift 中使用滚动视图滚动图像

Posted 2023-03-16

【中文标题】无法在 swift 中使用滚动视图滚动图像

【英文标题】：Unable to scroll image using scroll view in swift

【发布时间】：2017-06-06 16:54:24

【问题描述】：

我在快速滚动视图中遇到了这个奇怪的问题，即使在文件中定义滚动视图后图像也不会滚动，我还添加了缩放并且效果很好。请在这件事上给予我帮助 https://pastebin.com/1uC3fqHG

import UIKit

class ImageViewController: UIViewController

    var imageURL: URL? 
        didSet 
            image = nil
            if view.window != nil 
                fetchImage()
            
        
    

    private func fetchImage() 
        if let url = imageURL 
            let urlContents = try? Data(contentsOf: url)
            if let imageData = urlContents 
                image = UIImage(data: imageData)
            
        
    

    override func viewDidLoad() 
        super.viewDidLoad()
        view.addSubview(imageView)
        imageURL = URL(string: "http://www.lamborghini.com/en-en/sites/en-en/files/DAM/lamborghini/share%20img/huracan-coupe-facebook-og.jpg")
    

    override func viewWillAppear(_ animated: Bool) 
        super.viewWillAppear(animated)
        if image == nil 
            fetchImage()
        

    

    @IBOutlet weak var scrollView: UIScrollView! 
        didSet 

            scrollView.delegate = self
            scrollView.minimumZoomScale = 0.03
            scrollView.maximumZoomScale = 2.0
            scrollView.contentSize = imageView.frame.size
            scrollView.addSubview(imageView)
        
    


    fileprivate var imageView = UIImageView()

    private var image: UIImage? 
        get
            return imageView.image
        
        set
            imageView.image = newValue
            imageView.sizeToFit()
            scrollView?.contentSize = imageView.frame.size
        
    


extension ImageViewController: UIScrollViewDelegate

    func viewForZooming(in scrollView: UIScrollView) -> UIView? 
        return imageView
    

【参考方案1】：

问题是您在 viewDidLoad() 中将图像添加到视图中。从 viewDidLoad() 中删除 view.addSubview(imageView) ，一切都会正常工作。 代码会变成如下

import UIKit

class ImageViewController: UIViewController

    var imageURL: URL? 
        didSet 
            image = nil
            if view.window != nil 
                fetchImage()
            
        
    

    private func fetchImage() 
        if let url = imageURL 
            let urlContents = try? Data(contentsOf: url)
            if let imageData = urlContents 
                image = UIImage(data: imageData)
            
        
    

    override func viewDidLoad() 
        super.viewDidLoad()
        imageURL = URL(string: "http://www.lamborghini.com/en-en/sites/en-en/files/DAM/lamborghini/share%20img/huracan-coupe-facebook-og.jpg")
    

    override func viewWillAppear(_ animated: Bool) 
        super.viewWillAppear(animated)
        if image == nil 
            fetchImage()
        

    

    @IBOutlet weak var scrollView: UIScrollView! 
        didSet 

            scrollView.delegate = self
            scrollView.minimumZoomScale = 0.03
            scrollView.maximumZoomScale = 2.0
            scrollView.contentSize = imageView.frame.size
            scrollView.addSubview(imageView)
        
    


    fileprivate var imageView = UIImageView()

    private var image: UIImage? 
        get
            return imageView.image
        
        set
            imageView.image = newValue
            imageView.sizeToFit()
            scrollView?.contentSize = imageView.frame.size
        
    


extension ImageViewController: UIScrollViewDelegate

    func viewForZooming(in scrollView: UIScrollView) -> UIView? 
        return imageView
    

【参考方案2】：

您应该更新内容大小并更新图像视图约束检查此tutorial