CODEWITHSUNDEEP
iosswiftpersistencensuserdefaults
ferryawijayanto
ferryawijayanto

Reputation: 649

Persist app when terminate using UserDefaults

I want to save image using userdefaults, what I want to achieve is after image being change and the app terminate it. the image user change is still there. how do I achieve this with userdefaults.

This is my code when user pick image and save it in userdefaults

var data: Data? //I make a reference data to save imageData in pickerController
@objc func handleImagePicker() {
    let imagePickerController = UIImagePickerController()
    imagePickerController.allowsEditing = true
    imagePickerController.sourceType = .photoLibrary
    imagePickerController.delegate = self

    present(imagePickerController, animated: true)
}

@objc func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    if let editedImage = info[.editedImage] as? UIImage {
        guard let imageData = editedImage.jpegData(compressionQuality: 0.5) else { return }
        self.data = NSKeyedArchiver.archivedData(withRootObject: imageData)
        UserDefaults.standard.set(data, forKey: "profileImageEditedKey")
        UserDefaults.standard.synchronize()
        profileImageView.image = editedImage.withRenderingMode(.alwaysOriginal)
    } else if let originalImage = info[.originalImage] as? UIImage {
        guard let imageData = originalImage.jpegData(compressionQuality: 1) else { return }
        self.data = NSKeyedArchiver.archivedData(withRootObject: imageData)
        UserDefaults.standard.set(data, forKey: "profileImageOriginalKey")
        UserDefaults.standard.synchronize()
        profileImageView.image = originalImage.withRenderingMode(.alwaysOriginal)
    }
    dismiss(animated: true)
}

This is the code I place in viewWillAppear when I fetch the data after the app terminate

private func fetchData() {
    guard let data = data else { return }
    guard let image = NSKeyedUnarchiver.unarchiveObject(with: data) as? UIImage else { return }

    profileImageView.image = image.withRenderingMode(.alwaysOriginal)
    print("fetch...")
}

Upvotes: 0

Views: 80

Answers (1)

Ethan
Ethan

Reputation: 471

  1. it is not a good idea to save big data in userdefaults, it is often not recommended as it is not the most efficient way to save images; a more efficient way is to save your image in the application's Documents Directory. you use Data write func to do that. there are other third library too.

  2. if you insist using UserDefaults

    to save image

    guard let imageData = editedImage.jpegData(compressionQuality: 0.5) else { return }
UserDefaults.standard.set(imageData, forKey: "profileImageEditedKey")
UserDefaults.standard.synchronize()

    to get image from UserDefaults

    guard let data = UserDefaults.standard.object(forKey: "profileImageOriginalKey") as? Data else {
    return;
}
let image = UIImage.init(data: data);

Upvotes: 1

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