ios - Swift:拖放，保存来自谷歌图像的图像网址

Question

我正在尝试创建一个由 Collection View 组成的应用程序，其中将图像拖到其上。

我正在双显示器中打开谷歌图像，搜索“密封件”并将密封件的第一张图像拖到我的应用程序的 View Controller 上。我的应用程序应该保存图像的网址。 Collection View 中的每个单元格都会从保存的 url 中获得一个 url。设置 url 后，单元格会从 url 检索图像并将图像放置在自身内部。

问题是采用了错误的网址。获取的 url 可以转换为数据，但该数据无法转换为 UIImage。拖放保存的网址不是图像的网址，它似乎是谷歌搜索或其他东西的网址。

我需要能够保存图像的正确网址，以便 ImageCell 可以从该网址加载图像。

---

当我在网络浏览器中输入网址时，我会收到这样的页面。

ImageViewController

import UIKit

class ImageViewController: UIViewController{

    @IBOutlet weak var collectionView: UICollectionView!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    var gallery = [URL]()

}

extension ImageViewController: UICollectionViewDelegate, UICollectionViewDataSource{

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return gallery.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ImageCell", for: indexPath) as! ImageCell
        cell.url = gallery[indexPath.item]
        return cell
    }
}

extension ImageViewController: UICollectionViewDropDelegate{

    func collectionView(_ collectionView: UICollectionView, canHandle session: UIDropSession) -> Bool {
        return session.canLoadObjects(ofClass: NSURL.self) && session.canLoadObjects(ofClass: UIImage.self)
    }

    func collectionView(_ collectionView: UICollectionView, dropSessionDidUpdate session: UIDropSession, withDestinationIndexPath destinationIndexPath: IndexPath?) -> UICollectionViewDropProposal {
        return UICollectionViewDropProposal(operation: .copy)
    }

    func collectionView(_ collectionView: UICollectionView, performDropWith coordinator: UICollectionViewDropCoordinator) {

        // Get the destion index path, if there's none set, just insert at the beginning
        let destinationIndexPath = coordinator.destinationIndexPath ?? IndexPath(item: 0, section: 0)

        // Process all items being dragged
        for item in coordinator.items {

                // External drops must provide url and an image that we'll use to get an aspect-ratio
                var url: URL?

                // Get the URL
                item.dragItem.itemProvider.loadObject(ofClass: NSURL.self) { [weak self] (provider, error) in

                    url = provider as? URL  //Check that url is valid

                    // If both url and ratio were provided, perform the actual drop
                    if url != nil{
                        DispatchQueue.main.async {
                            collectionView.performBatchUpdates({
                                // Update model
                                self?.gallery.insert(url!, at: destinationIndexPath.item)

                                // Update view
                                collectionView.insertItems(at: [destinationIndexPath])

                                // Animates the item to the specified index path in the collection view.
                                coordinator.drop(item.dragItem, toItemAt: destinationIndexPath)
                            })
                        }
                    }
                }
            }

    }

}

ImageCell

class ImageCell: UICollectionViewCell{
    var url: URL?{
        didSet{
            self.fetchImage(withURL: url!)
        }
    }
    @IBOutlet var imageView: UIImageView!

    private func fetchImage(withURL url: URL) {
        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
            guard let data = try? Data(contentsOf: url) else {
                return
            }

            guard let image = UIImage(data: data) else {
                print("Couldn't convert data to UIImage")
                print("The url is")
                print(url)
                return
            }

            // If by the time the async. fetch finishes, the imageURL is still the same, update the UI (in the main queue)
            if self?.url == url {
                DispatchQueue.main.async {
                    self?.imageView.image = image
                }
            }
        }
    }

}

---

GITHUB

Here is my project on github

Answer 1

要从通过拖放 Google 图片提供的 URL 中提取图片 URL，您可以将这些扩展名添加到 URL。然后，在保存 url 的变量 (url) 上，您可以使用 url!.imageURL 而不仅仅是 url! 来访问图像 url >

extension URL {
    var imageURL: URL {
        if let url = UIImage.urlToStoreLocallyAsJPEG(named: self.path) {
            // this was created using UIImage.storeLocallyAsJPEG
            return url
        } else {
            // check to see if there is an embedded imgurl reference
            for query in query?.components(separatedBy: "&") ?? [] {
                let queryComponents = query.components(separatedBy: "=")
                if queryComponents.count == 2 {
                    if queryComponents[0] == "imgurl", let url = URL(string: queryComponents[1].removingPercentEncoding ?? "") {
                        return url
                    }
                }
            }
            return self.baseURL ?? self
        }
    }
}

extension UIImage
{
    private static let localImagesDirectory = "UIImage.storeLocallyAsJPEG"

    static func urlToStoreLocallyAsJPEG(named: String) -> URL? {
        var name = named
        let pathComponents = named.components(separatedBy: "/")
        if pathComponents.count > 1 {
            if pathComponents[pathComponents.count-2] == localImagesDirectory {
                name = pathComponents.last!
            } else {
                return nil
            }
        }
        if var url = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first {
            url = url.appendingPathComponent(localImagesDirectory)
            do {
                try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
                url = url.appendingPathComponent(name)
                if url.pathExtension != "jpg" {
                    url = url.appendingPathExtension("jpg")
                }
                return url
            } catch let error {
                print("UIImage.urlToStoreLocallyAsJPEG \(error)")
            }
        }
        return nil
    }

    func storeLocallyAsJPEG(named name: String) -> URL? {
        if let imageData = self.jpegData(compressionQuality: 1.0) {
            if let url = UIImage.urlToStoreLocallyAsJPEG(named: name) {
                do {
                    try imageData.write(to: url)
                    return url
                } catch let error {
                    print("UIImage.storeLocallyAsJPEG \(error)")
                }
            }
        }
        return nil
    }
}