尝试在 USerDefault 中保存图像时我做错了什么

Question

我需要获取图像，然后将其保存到 UserDefaults 以便能够检索它。但是，我尝试另存为 UIImage，但是当我尝试检索图像时，应用程序崩溃了。对我来说最好的方法是什么？

我就是这样保存图片的

import UIKit

protocol dataReceivedDelegate {
    func dataReceived(fotoSaved:[UIImage],nameSaved:NSArray)
}

class adicionarNovoItemVc: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UITextFieldDelegate {

    @IBOutlet weak var textFieldNome: UITextField!
    let imagePicker = UIImagePickerController()
    @IBOutlet weak var namePreview: UILabel!
    @IBOutlet weak var imagePreview: UIImageView!
    let picker = UIImagePickerController()
    var arrayName = [String]()
    var arrayFoto = [UIImage]()
    var delegate:dataReceivedDelegate? = nil

    override func viewDidLoad() {
        super.viewDidLoad()
        self.textFieldNome.delegate = self
        // Do any additional setup after loading the view.
        if isKeyPresentInUserDefaults(key: "namesSavedArray") == true{
            arrayName = UserDefaults.standard.array(forKey: "namesSavedArray") as! [String]
        }
        if isKeyPresentInUserDefaults(key: "fotoSavedArray") == true{
            arrayFoto = UserDefaults.standard.array(forKey: "fotoSavedArray") as! [UIImage]
        }
    }
    func isKeyPresentInUserDefaults(key: String) -> Bool {
        return UserDefaults.standard.object(forKey: key) != nil
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[.originalImage] as? UIImage {
            self.imagePreview.image = image
            self.namePreview.text = self.textFieldNome.text
        }
        self.picker.dismiss(animated: true, completion: nil)
    }


    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        self.textFieldNome.resignFirstResponder()
        return true
    }

    @IBAction func botaoAdcItem(_ sender: UIButton) {
        if (self.namePreview!.text != nil) && (self.imagePreview!.image != nil) {
            if delegate != nil {

                arrayName.append(self.namePreview.text!)
                arrayFoto.append(self.imagePreview.image!)

                delegate?.dataReceived(fotoSaved: arrayFoto, nameSaved: arrayName as NSArray)

                UserDefaults.standard.set(arrayName, forKey: "namesSavedArray")
                UserDefaults.standard.set(arrayFoto, forKey: "fotoSavedArray")

            self.navigationController?.popViewController(animated: true)
            }
        }
        else {return}
}

Answer 1

您不能也不应该将图像存储到 UserDefaults。 UserDefaults 旨在保存用户输入的字符串或首选项设置等简短内容。

它只能保存一小部分数据类型（"property list" 对象：Array、Dictionary、String、Data、Date、整数类型、浮点类型或 Bools）。任何其他数据类型都将失败。

我建议将图片保存到用户的Documents目录下，然后在UserDefaults.

中保存文件的路径

Answer 2

如@Duncan-c 所说，您不应将其保存在 UserDefaults 中。您可以在 UserDefaults 中保存选定的文件名 (URL) 并在下次使用时使用文件名 (URL) 加载实际图像。

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
  if let imageURL = info[UIImagePickerControllerImageURL] as! URL? {
    UserDefaults.standard.set(imageURL, forKey: "SelectedImage")
    UserDefaults.standard.synchronize()
  }

  ...  
  picker.dismiss(animated: true, completion: nil)

}

// Load the image
if let imageURL = UserDefaults.standard.url(forKey: "SelectedImage") {
   if let data = NSData(contentsOf: imageURL) as NSData? {
      self. imagePreview.image = UIImage(data: data as Data)
   }
}

尝试在 USerDefault 中保存图像时我做错了什么

What am I doing wrong on try to save image in USerDefault

ios

swift

nsuserdefaults