在“UIKit for Mac”平台上如何使用SwiftUI打开文件对话框？

Question

在"UIKit for Mac"平台上无法使用NSOpenPanel: https://developer.apple.com/documentation/appkit/nsopenpanel

如果苹果没有提供内置方式，那么我猜有人会基于SwiftUI和FileManager创建一个库，用于显示选择文件的对话框。

- Ngoc Dao

Answer 1

以下是一种在Catalyst和UIKit下选择macOS文件的解决方案

在您的SwiftUI视图中：

Button("Choose file") {
    let picker = DocumentPickerViewController(
        supportedTypes: ["log"], 
        onPick: { url in
            print("url : \(url)")
        }, 
        onDismiss: {
            print("dismiss")
        }
    )
    UIApplication.shared.windows.first?.rootViewController?.present(picker, animated: true)
}

DocumentPickerViewController 类:

class DocumentPickerViewController: UIDocumentPickerViewController {
    private let onDismiss: () -> Void
    private let onPick: (URL) -> ()

    init(supportedTypes: [String], onPick: @escaping (URL) -> Void, onDismiss: @escaping () -> Void) {
        self.onDismiss = onDismiss
        self.onPick = onPick

        super.init(documentTypes: supportedTypes, in: .open)

        allowsMultipleSelection = false
        delegate = self
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

extension DocumentPickerViewController: UIDocumentPickerDelegate {
    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        onPick(urls.first!)
    }

    func documentPickerWasCancelled(_ controller: UIDocumentPickerViewController) {
        onDismiss()
    }
}

- Anthony

---

优秀的解决方案。我已经寻找了一段时间，但一直没有成功。恭喜。 - Cesare Piersigilli

Answer 2

UIDocumentPickerViewController和UIDocumentBrowserViewController在Catalyst中都可以使用。您可以像在iOS上一样使用它们，它们将“神奇地”显示为标准的Mac打开/保存对话框。

如果您需要，这里有一个不错的示例：https://appventure.me/guides/catalyst/how/open_save_export_import.html

- Adam