Swift 中的 UIImagePickerController 图像

Posted 2023-02-23

【中文标题】Swift 中的 UIImagePickerController 图像

【英文标题】：UIImagePickerController image in Swift

【发布时间】：2017-04-14 19:11:56

【问题描述】：

我在我的程序中使用 UIImagePickerController，它有效地改变了我添加的图像视图的图像。但是，每当我重新启动此应用程序并返回主屏幕时，它会自动重置为我之前使用的默认图像，而不是用户选择的图像。我怎样才能让它记录上次使用的图像，并在每次程序启动时重新加载它？

 var imagePicker = UIImagePickerController()
 func chooseImage(_ sender: Any)  //function called with button press

    let imagePickerController = UIImagePickerController()
    imagePickerController.delegate = self
    imagePickerController.allowsEditing = true

    let actionSheet = UIAlertController(title: "Photo Source", message: "Choose a source", preferredStyle: .actionSheet)

    actionSheet.addAction(UIAlertAction(title: "Camera", style: .default, handler:  (action:UIAlertAction) in

        if UIImagePickerController.isSourceTypeAvailable(.camera) 
            imagePickerController.sourceType = .camera
            self.present(imagePickerController, animated: true, completion: nil)
        else
            print("Camera not available")
        


    ))

    actionSheet.addAction(UIAlertAction(title: "Photo Library", style: .default, handler:  (action:UIAlertAction) in
        imagePickerController.sourceType = .photoLibrary
        self.present(imagePickerController, animated: true, completion: nil)
    ))

    actionSheet.addAction(UIAlertAction(title: "Default", style: .default, handler:  (action:UIAlertAction) in
        self.avatarImageView.image = UIImage(named: "Avatar.png")


    ))

    actionSheet.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

    self.present(actionSheet, animated: true, completion: nil)




func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) 
    let image = info[UIImagePickerControllerEditedImage] as! UIImage

    avatarImageView.image = image

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





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

【问题讨论】：

我假设您的意思是实际的应用重启（即内存不足），而不是仅仅点击主屏幕然后重新启动应用？

您需要将图像保存在某处，并在您的应用下次启动时加载它

@LeoDabus 我该怎么做？请指导我。

另存为 jpeg ***.com/questions/29726643/…

你需要有某种持久层。你可以使用数据库、Core Data 甚至 NSUserDefaults。稍后我会尝试整理一个示例。

【参考方案1】：

由于应用程序内存不足，您需要某种持久性机制来保存图像。最简单的方法是将图像存储在UserDefaults 中。这可以这样完成：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) 

    let image = info[UIImagePickerControllerEditedImage] as! UIImage
    avatarImageView.image = image
    UserDefaults.standard.set(UIImagePNGRepresentation(image), forKey: "avatarImage")    

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

然后，当您重新打开应用程序时，您需要检查您之前是否在UserDefaults 中保存了头像图像并从那里加载：

// Could be in viewDidLoad or wherever else you load your image
override func viewDidLoad() 

    if let imageData = UserDefaults.standard.object(forKey: "avatarImage") as? Data 
        avatarImageView.image = UIImage(data: imageData)