无法在 swift 中使用滚动视图滚动图像答案

【问题标题】：Unable to scroll image using scroll view in swift无法在 swift 中使用滚动视图滚动图像
【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
    }
}

【问题讨论】：

标签： ios swift

【解决方案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
    }
}

【讨论】：

【解决方案2】：

您应该更新内容大小并更新图像视图约束检查此tutorial

【讨论】：