CloudDocument

CloudDocument uses UIDocument to coordinate access to iCloud documents, providing a simple and powerful API for handling conflicts related to syncing with iCloud documents. It is suitable for both SwiftUI and UIKit applications.

Features

• Asynchronous and error-handling based API.
• Simple and powerful API for controlling file saving.
• Simple and powerful API for handling cloud file conflicts.
• Renaming of URL from UIDocumentBrowserViewController in a document-based application on UIKit or SwiftUI in iOS 16.0.
• A class CloudTextPresenter for automatically processing text files and text encoding has been provided.

Usage Example

Detailed descriptions of all documents are available in the source code files. Here is a brief overview of how to use it.

Make Data Structure Conform to CloudFileModel Protocol

For example, here is an example of making the String type conform to the CloudFileModel protocol.

extension String: CloudFileModel {
    public typealias DataInfo = String.Encoding
    public static func createEmptyModel() -> String {
        .init()
    }
    public static func createModel(from data: Data) throws -> String {
        String(data: data, encoding: self.dataInfo!) ?? .init()
    }
    public func accessModelData() throws -> Data {
        guard let data = self.data(using: self.dataInfo!) else {
            throw CocoaError(.fileReadInapplicableStringEncoding)
        }
        return data
    }
     var dataInfo: DataInfo? { .utf8 }
}

It is important to note that types conforming to this protocol must be valuable semantics. Otherwise it will lead to unexpected behavior.

Load File Model and Use in SwiftUI

Here is an example code snippet.

import SwiftUI
import UIKit

struct DocumentEditor: View {
    @StateObject var document: CloudFilePresenter<String>
    var body: some View {
        Text(self.document.content)
    }
}

class DocumentBrowserViewController: UIDocumentBrowserViewController {
    func presentDocument(at url: URL) async throws {
        let document = try await CloudFilePresenter<String>(fileURL: url, documentBrowser: self)
        let hostViewController = UIHostingController(rootView: DocumentEditor(model: document))
        hostViewController.modalPresentationStyle = .fullScreen
        hostViewController.sizingOptions = .preferredContentSize
        self.present(hostViewController, animated: true)
    }
}

Notes

If you want to fully utilize SwiftUI for editing documents in a UIKit-based document class app, you need to remove the Storyboard, otherwise it may cause abnormal sizes for SwiftUI views.