Dans cet article, nous verrons comment mettre en cache des images dans une application Swift pour améliorer les performances de…

import UIKit

class ImageCache {
  // MARK: - Properties

  private let cache = NSCache<NSString, UIImage>()

  // MARK: - Caching

  func cache(image: UIImage, forKey key: String) {
    cache.setObject(image, forKey: key as NSString)
  }

  func image(forKey key: String) -> UIImage? {
    return cache.object(forKey: key as NSString)
  }
}

let cache = ImageCache()

let image = UIImage(named: "myImage")
cache.cache(image: image, forKey: "myImage")

let cachedImage = cache.image(forKey: "myImage")

import UIKit

extension UIImageView {
  private struct AssociatedKeys {
    static var imageCache = "imageCache"
  }

  var imageCache: ImageCache {
    get {
      if let cache = objc_getAssociatedObject(self, &AssociatedKeys.imageCache) as? ImageCache {
        return cache
      }

      let cache = ImageCache()
      objc_setAssociatedObject(self, &AssociatedKeys.imageCache, cache, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
      return cache
    }
  }

  func cache(image: UIImage, forKey key: String) {
    imageCache.cache(image: image, forKey: key)
  }

  func cachedImage(forKey key: String) -> UIImage? {
    return imageCache.image(forKey: key)
  }
}

import UIKit

class ImageCache {
  // MARK: - Properties

  private let cache = NSCache<NSString, UIImage>()

  // MARK: - Caching

  func cache(image: UIImage, forKey key: String) {
    cache.setObject(image, forKey: key as NSString)
  }

  func image(forKey key: String) -> UIImage? {
    return cache.object(forKey: key as NSString)
  }

  func clearCache() {
    cache.removeAllObjects()
  }

  func loadImage(fromURL url: URL, forKey key: String, completion: @escaping (UIImage?) -> Void) {
    if let image = image(forKey: key) {
      completion(image)
      return
    }

    URLSession.shared.dataTask(with: url) { data, response, error in
      if let data = data, let image = UIImage(data: data) {
        self.cache(image: image, forKey: key)
        completion(image)
      } else {
        completion(nil)
      }
    }.resume()
  }
}

let cache = ImageCache()

let imageURL = URL(string: "https://example.com/image.png")!
cache.loadImage(fromURL: imageURL, forKey: "imageKey") { image in
  // Use the image here
}

cache.clearCache()