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November 29, 2016 18:52
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ImageStore.swift for the advanced ios bootcamp pre-reading
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// | |
// Copyright © 2015 Big Nerd Ranch | |
// | |
import UIKit | |
class ImageStore { | |
let cache = NSCache<NSString, UIImage>() | |
func imageURL(forKey key: String) -> URL { | |
let documentsDirectories = | |
FileManager.default.urls(for: .documentDirectory, | |
in: .userDomainMask) | |
let documentDirectory = documentsDirectories.first! | |
return documentDirectory.appendingPathComponent(key) | |
} | |
func setImage(_ image: UIImage, forKey key: String) { | |
cache.setObject(image, forKey: key as NSString) | |
// Create full URL for image | |
let url = imageURL(forKey: key) | |
// Turn image into JPEG data | |
if let data = UIImageJPEGRepresentation(image, 0.5) { | |
// Write it to full URL | |
let _ = try? data.write(to: url, options: [.atomic]) | |
} | |
} | |
func image(forKey key: String) -> UIImage? { | |
if let existingImage = cache.object(forKey: key as NSString) { | |
return existingImage | |
} else { | |
let url = imageURL(forKey: key) | |
guard let imageFromDisk = UIImage(contentsOfFile: url.path) else { | |
return nil | |
} | |
cache.setObject(imageFromDisk, forKey: key as NSString) | |
return imageFromDisk | |
} | |
} | |
func deleteImage(forKey key: String) { | |
cache.removeObject(forKey: key as NSString) | |
let url = imageURL(forKey: key) | |
do { | |
try FileManager.default.removeItem(at: url) | |
} catch { | |
print("Error removing the image from disk: \(error)") | |
} | |
} | |
} |
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