iphone - 在 Swift 中存储和获取图像？

Question

我需要你的帮助。我需要将相机中的图片保存到 ImageView 中。当我打开应用程序时，图片必须出现在那里，但我不知道它是如何工作的。我是初学者，所以非常感谢您的帮助/提示 :) 谢谢。

更具体地说，我用手机拍了一张照片，照片出现了，但当我关闭应用程序时，它就不再存在了。我应该使用 NSUser 默认值吗？？？

Answer 1

如果你想保存简单的照片，你可以使用UserDefaults。您需要将图像转换为 NSData，然后才能保存在 UserDefaults 中。这是示例代码。

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

@IBOutlet weak var imageView: UIImageView!

override func viewDidLoad() {
    super.viewDidLoad()

    // Load saved image
    loadImageFromUserDefaults()
}

private func loadImageFromUserDefaults() {
    guard let imageData = UserDefaults.standard.data(forKey: "image_data") as NSData? else {
        print("No image saved")
        return
    }
    let image = UIImage(data: imageData as Data)
    imageView.image = image
}

private func saveImageToUserDefaults(image: UIImage) {
    guard let data = UIImageJPEGRepresentation(image, 1.0) as NSData? else {
        print("Failed to convert image")
        return
    }
    UserDefaults.standard.set(data, forKey: "image_data")
    UserDefaults.standard.synchronize()
}

@IBAction func selectPhoto(_ sender: Any) {
    let imagePickerController = UIImagePickerController()
    imagePickerController.sourceType = .photoLibrary
    imagePickerController.delegate = self
    self.present(imagePickerController, animated: true, completion: nil)
}

// UIImagePickerControllerDelegate

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {
        saveImageToUserDefaults(image: image)
        loadImageFromUserDefaults()
    }
    self.dismiss(animated: true, completion: nil)
}

func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
    picker.dismiss(animated: true, completion: nil)
}
}