Swift - 使用异步方法加载 PHPickerResult

Question

I am trying to load a user selected image from photos using PHPickerViewController's delegate method. I know that I can do that with result.itemProvider.loadObject; however, I want to use an async version of that method that does not require a completion handler. This is what I tried:

func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
    Task {
        do {
            for result in results {
                let x = try await result.itemProvider.loadItem(forTypeIdentifier: String(describing: UIImage.self)) as? UIImage
            }
        } catch {
            print("parsing_error")
        }
    }
}

I am getting a parsing error. To be honest, I'm not sure how itemProvider.loadItem works exactly, and I've had trouble finding much info on it. Any recommendations?

Answer 1

I don't know why your code doesn't work. (It doesn't work for me either, for what it's worth.) However, I did determine code that does work, although you might not consider it to be an improvement over just using loadObject with a callback:

Task {
    do {
        let url = try await item.loadItem(forTypeIdentifier: "public.image") as! URL
        let data = try Data(contentsOf: url)
        if let image = UIImage(data: data) {
            print("Image loaded: \(image)")
        } else {
            print("Error loading image!");
        }
    } catch let error {
        print("async loadItem failed: \(error)")
    }
}

Note: I tried to use UIImage(contentsOfFile: url.absoluteString) instead of loading the URL into a Data object and then loading the UIImage from that. That didn't work, and I don't know why. All I know is that UIImage(contentsOfFile:) returned nil.