在Swift中从ImagePickerControllerImageURL在UserDefaults中保存并追加一个数组

问题描述

我在从UIImagePickerControllerImageURL中保存和检索UserDefaults中的数组时遇到问题.同步后可以获取数组，但是无法检索它.myArray为空.

I'm having an issue saving and retrieving an array in UserDefaults from UIImagePickerControllerImageURL. I can get the array after synchronizing, but I am unable to retrieve it. myArray is empty.

testImage.image确实获得了图像，在那里没有问题.

The testImage.image does get the image, no problems there.

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    let imageURL: URL = info[UIImagePickerControllerImageURL] as! URL

    //test that imagepicker is actually getting the image
    let imageData: NSData = try! NSData(contentsOf: imageURL)
    let cvImage = UIImage(data:imageData as Data)
    testImage.image = cvImage

    //Save array to UserDefaults and add picked image url to the array
    let usD = UserDefaults.standard
    var array: NSMutableArray = []
    usD.set(array, forKey: "WeatherArray")
    array.add(imageURL)
    usD.synchronize()
    print ("array is \(array)")

    let myArray = usD.stringArray(forKey:"WeatherArray") ?? [String]()
    print ("myArray is \(myArray)")

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

推荐答案

这里有很多问题.

1. 请勿使用 NSData ，而应使用 Data .
2. 请勿使用 NSMutableArray ，而应使用Swift数组.
3. 您可以直接从 info 字典中获取 UIImage .
4. 您不能将URL存储在 UserDefaults 中.
5. 在使用新的URL更新阵列之前，将 array 保存到 UserDefaults .
6. 您创建一个新数组，而不是从 UserDefaults 获取当前数组.
7. 您不必要地调用同步.
8. 您无需为大多数变量指定类型.

1. Do not use NSData, use Data.
2. Do not use NSMutableArray, use a Swift array.
3. You can get the UIImage directly from the info dictionary`.
4. You can't store URLs in UserDefaults.
5. You save array to UserDefaults before you update the array with the new URL.
6. You create a new array instead of getting the current array from UserDefaults.
7. You needlessly call synchronize.
8. You needlessly specify the type for most of your variables.

以下是您的代码已更新，可解决所有这些问题:

Here is your code updated to fix all of these issues:

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    if let image = info[UIImagePickerControllerOriginalImage] as? UIImage {
        testImage.image = image
    }

    if let imageURL = info[UIImagePickerControllerImageURL] as? URL {
        //Save array to UserDefaults and add picked image url to the array
        let usD = UserDefaults.standard
        var urls = usD.stringArray(forKey: "WeatherArray") ?? []
        urls.append(imageURL.absoluteString)
        usD.set(urls, forKey: "WeatherArray")
    }

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

请注意，这会保存代表每个URL的字符串数组.稍后，当您访问这些字符串时，如果需要 URL ，则需要使用 URL(string:arrayElement).

Note that this saves an array of strings representing each URL. Later on, when you access these strings, if you want a URL, you need to use URL(string: arrayElement).

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