快速在 UIImageView 上创建缩放
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【中文标题】快速在 UIImageView 上创建缩放【英文标题】：Creating zoom on UIImageView in swift 【发布时间】：2018-12-09 01:48:03 【问题描述】：我目前正在从我的服务器加载图像。图像很多，具体取决于它返回的图像数量。我已经能够成功显示这些图像，并且可以向下滚动查看所有图像。现在我的问题是我想要一种可以单击特定图像的方式，我将能够对其进行缩放。我在下面分享了我的代码：
//Declaration of variables
var albumID: String?
var imagePath: String?
var path: String?
var getClickImage = UIImageView()
var zoomscrollV = UIScrollView()
var imageArray = [String]()
//view did load
override func viewDidLoad()
super.viewDidLoad()
setUpViewsAlbumPhotos()
zoomscrollV.delegate = self
if !CheckInternet.Connection()
showAlert(title: "No Internet", message: "Please connect your device to an internet connection")
else
fetchPhotos(albumID: albumID)
//viewDidAppear
override func viewDidAppear(_ animated: Bool)
super.viewDidAppear(animated)
zoomscrollV.isHidden = true
zoomscrollV.frame = CGRect(x:0, y:0, width:self.view.frame.width, height:self.view.frame.height - 50)
zoomscrollV.minimumZoomScale=1
zoomscrollV.maximumZoomScale=10
zoomscrollV.bounces=false
self.view.addSubview(zoomscrollV)
getClickImage=UIImageView()
getClickImage.frame = CGRect(x:0, y:0, width:zoomscrollV.frame.width, height:zoomscrollV.frame.height)
getClickImage.backgroundColor = .black
getClickImage.contentMode = .scaleAspectFit
zoomscrollV.addSubview(getClickImage)
//This code makes an async call to download images and details from the server
let async_call = URL(string: "\(String.api_albumPhotos)\(albumID ?? "")")
let request = NSMutableURLRequest(url: async_call!)
request.httpMethod = "GET"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
let task = URLSession.shared.dataTask(with: request as URLRequest)
data, response, error in
if error != nil
print("error is:: \(error!.localizedDescription)")
DispatchQueue.main.async
self.showAlert(title: "Error", message: "Sorry try again later")
self.stopActivityLoader()
return
do
let myJSON = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
if let parseJSON = myJSON
var responseCode: String!
var message: NSArray!
responseCode = parseJSON["responseCode"] as! String?
if responseCode == "200"
DispatchQueue.main.async
self.stopActivityLoader()
message = parseJSON["message"] as? NSArray
self.path = parseJSON["path"] as? String
if let message = message
let totalMessage = message.count
let viewHeight = self.view.frame.height
var scrollHeight = 0
var contentViewTopConstraint: CGFloat = 20
// self.preference.set(parseJSON, forKey: UserDefaultKeys.albums.rawValue)
for obj in message
if let dict = obj as? NSDictionary
self.imagePath = dict.value(forKey: "path") as? String
let imageID = dict.value(forKey: "id") as? String
let albumThumbnail = photos()
self.scrollView.addSubview(albumThumbnail)
albumThumbnail.translatesAutoresizingMaskIntoConstraints = false
albumThumbnail.leadingAnchor.constraint(equalTo: self.contentView.leadingAnchor).isActive = true
albumThumbnail.topAnchor.constraint(equalTo: self.scrollView.topAnchor, constant: contentViewTopConstraint).isActive = true
albumThumbnail.trailingAnchor.constraint(equalTo: self.contentView.trailingAnchor).isActive = true
albumThumbnail.heightAnchor.constraint(equalToConstant: 150).isActive = true
albumThumbnail.isUserInteractionEnabled = true
albumThumbnail.contentMode = .scaleAspectFit
let touchRec = UITapGestureRecognizer(target: self, action: #selector(self.myImageTapped(_:)))
albumThumbnail.addGestureRecognizer(touchRec)
if let path = self.path
if let imagePath = self.imagePath
let strippedPath = path.replacingOccurrences(of: "\\", with: "")
let strippedImagePath = imagePath.replacingOccurrences(of: "\\", with: "")
print("\(strippedPath)\(strippedImagePath)")
albumThumbnail.sd_setImage(with: URL(string: "\(strippedPath)\(strippedImagePath)"), placeholderImage: UIImage(named: "default_profile"), options: [.continueInBackground, .progressiveDownload])
if let wrapped = self.path
self.imageArray.append("\(strippedPath)\(strippedImagePath)")
// print(self.imageArray.append(wrapped))
contentViewTopConstraint = contentViewTopConstraint + 170
scrollHeight = totalMessage * 170
if totalMessage <= 1
self.scrollView.contentSize.height = viewHeight + 20
else
self.scrollView.contentSize.height = CGFloat(scrollHeight)
else
//Show alert
DispatchQueue.main.async
self.showAlert(title: "Error", message: "Sorry could not update album. Try again")
self.stopActivityLoader()
catch
print("you:: \(error.localizedDescription)")
//Show alert
DispatchQueue.main.async
self.showAlert(title: "Error", message: "Sorry could not update album. Try again")
self.stopActivityLoader()
task.resume()
@objc func myImageTapped(_ sender: UITapGestureRecognizer)
zoomscrollV.isHidden = false
let myImage = imageArray[(sender.view?.tag)!]
print("myImage \(myImage)")
// RESPECTIVE IMAGE
getClickImage.image = UIImage(named: myImage)
let closeButton: UIButton = UIButton(type: .custom)
closeButton.frame = CGRect(x:40.0, y:self.view.frame.height - 50, width:self.view.frame.width - 80, height:50.0)
closeButton.addTarget(self, action: #selector(self.closeZoom), for: .touchUpInside)
closeButton.setTitle("CLOSE ZOOM", for: .normal)
closeButton.setTitleColor(UIColor.white, for: .normal)
// CLOSE BUTTON
self.view.addSubview(closeButton)
``
@objc func closeZoom(sender: AnyObject)
zoomscrollV.isHidden = true
zoomscrollV.setZoomScale(1.0, animated: false)
sender.removeFromSuperview()
//SCROLLVIEW DELEGATE
func viewForZooming(in scrollView: UIScrollView) -> UIView?
return getClickImage
【问题讨论】：
【参考方案1】：=========================== 编辑 1 月 24 日 =============== =============
将网址转换为图片
@objc func myImageTapped(_ sender: UITapGestureRecognizer)
zoomscrollV.isHidden = false
let myImageURL = imageArray[(sender.view?.tag)!]
if let url = URL( string: myImageURL)
DispatchQueue.global().async
if let data = try? Data( contentsOf:url)
DispatchQueue.main.async
let myImage = UIImage( data:data)
print("myImage \(myImage)")
// RESPECTIVE IMAGE
getClickImage.image = UIImage(named: myImage)
let closeButton: UIButton = UIButton(type: .custom)
closeButton.frame = CGRect(x:40.0, y:self.view.frame.height - 50, width:self.view.frame.width - 80, height:50.0)
closeButton.addTarget(self, action: #selector(self.closeZoom), for: .touchUpInside)
closeButton.setTitle("CLOSE ZOOM", for: .normal)
closeButton.setTitleColor(UIColor.white, for: .normal)
// CLOSE BUTTON
self.view.addSubview(closeButton)
================================================ ================
在图片点击时，你已经创建了滚动视图并将相应的图片添加为子视图，然后缩放将起作用。
var getClickImage = UIImageView()
var zoomscrollV = UIScrollView()
override func viewDidLoad()
super.viewDidLoad()
zoomscrollV.delegate = self
override func viewDidAppear(_ animated: Bool)
zoomscrollV.isHidden = true
zoomscrollV.frame = CGRect(x:0, y:0, width:self.view.frame.width, height:self.view.frame.height - 50)
zoomscrollV.minimumZoomScale=1
zoomscrollV.maximumZoomScale=10
zoomscrollV.bounces=false
self.view.addSubview(zoomscrollV)
getClickImage=UIImageView()
getClickImage.frame = CGRect(x:0, y:0, width:zoomscrollV.frame.width, height:zoomscrollV.frame.height)
getClickImage.backgroundColor = .black
getClickImage.contentMode = .scaleAspectFit
zoomscrollV.addSubview(getClickImage)
// ON CLICKING IMAGE ACTION
@objc func myImageTapped(_ sender: UITapGestureRecognizer)
zoomscrollV.isHidden = false
// RESPECTIVE IMAGE
getClickImage.image = BG_CARD_IMGS[(sender.view?.tag)!]
let closeButton: UIButton = UIButton(type: .custom)
closeButton.frame = CGRect(x:40.0, y:self.view.frame.height - 50, width:self.view.frame.width - 80, height:50.0)
closeButton.addTarget(self, action: #selector(self.closeZoom), for: .touchUpInside)
closeButton.setTitle("CLOSE ZOOM", for: .normal)
closeButton.setTitleColor(UIColor.red, for: .normal)
// CLOSE BUTTON
self.view.addSubview(closeButton)
@objc func closeZoom(sender: AnyObject)
zoomscrollV.isHidden = true
zoomscrollV.setZoomScale(1.0, animated: false)
sender.removeFromSuperview()
//SCROLLVIEW DELEGATE
func viewForZooming(in scrollView: UIScrollView) -> UIView?
return getClickImage
输出
【讨论】：
在你的代码中 BG_CARD_IMGS 是什么意思？我正在使用未解析的标识符。 那是你的图像数组。你如何在滚动视图中显示图像？点击第三张，getClickImage.image = YourImage [第三张图片]，点击第四张，getClickImage.image = YourImage [第四张图片]， 我显示的图像是通过 URL。所以我创建了一个像 var BG_CARD_IMGS = [String]() 这样的空数组，并在我的异步调用中添加了路径，比如 self.BG_CARD_IMGS.append(self.imagePath!)。但是在我的 myImageTapped 函数中这一行“getClickImage.image = imageArray[(sender.view?.tag)!]”。我收到此错误“无法将'String'类型的值分配给'UIImage？'” 所以，据我所知，您在图片点击时获得了正确的图片 URL。如果是，则在点击右图后，将 URL 转换为图片并将该图片存储在 getClickImage.image 中。 @chevi99 如果您对我的回答满意，请点赞并打勾。这对 SO 追随者很有用。以上是关于快速在 UIImageView 上创建缩放的主要内容，如果未能解决你的问题，请参考以下文章
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