iCloud > iCloud Documents

0. 準備: アプリ単位の ContainerID を設定
1. UIDocument を継承したクラスを作成する
   • contents() を override
   • load() を override
2. NSMetadataQuery でファイルのURLを特定
3. FileManager を使用してファイルの読み書き

・・・という感じだが、使うことがあったときにもう少し詳しく見よう。。

swift

class MyDocument: UIDocument {
	var fileContent: Data?
	
	override func contents(forType typeName: String) throws -> Any {
		return fileContent ?? Data()
	}
	override func load(fromContents contents: Any, ofType typeName: String?) throws {
		if let data = contents as? Data, !data.isEmpty {
			fileContent = data
		}
	}
}

swift

class ApplicationData: ObservableObject {
	var document: MyDocument!
	var metaData: NSMetadataQuery!
	
	init() {
		metaData = NSMetadataQuery()
		metaData.predicate = NSPredicate(format: "%K == %@", NSMetadataItemFSNameKey, "myfile.dat")
		metaData.searchScopes = [NSMetadataQueryUbiquitousDocumentsScope]
		Task(priority: .high) {
			let center = NotificationCenter.default
			let name = NSNotification.Name.NSMetadataQueryDidFinishGathering
			for await notification in center.notifications(named: name, object: metaData) {
				if notification.name == name {
					await createFile()
				}
			}
		}
		metaData.start()
	}
	
	@MainActor
	func createFile() async {
		if metaData.resultCount > 0 {
			let file = metaData.result(at: 0) as! NSMetadataItem
			let fileURL = file.value(forAttribute: NSMetadataItemURLKey) as! URL
			document = MyDocument(fileURL: fileURL)
		} else {
			let manager = FileManager.default
			if let fileURL = manager.url(forUbiquityContainerIdentifier: nil) {
				let documentURL = fileURL.appendingPathComponent("Documents/myfile.dat")
				document = MyDocument(fileURL: documentURL)
				document.fileContent = Data()
				if manager.fileExists(atPath: documentURL.path) {
					let _ = await document.save(to: documentURL, for: .forOverwriting)
				} else {
					let _ = await document.save(to: documentURL, for: .forCreating)
				}
			}
		}
	}
	
	@MainActor
	func openDocument() async -> String {
		let manager = FileManager.default
		if let fileURL = manager.url(forUbiquityContainerIdentifier: nil) {
			let documentURL = fileURL.appendingPathComponent("Documents/myfile.dat")
			document = MyDocument(fileURL: documentURL)
			let success = await document.open()
			if success {
				if let data = document.fileContent {
					return String(data: data, encoding: .utf8) ?? ""
				}
			}
		}
		return ""
	}
	
	@MainActor
	func saveDocument(text: String) async {
		let manager = FileManager.default
		if let fileURL = manager.url(forUbiquityContainerIdentifier: nil) {
			let documentURL = fileURL.appendingPathComponent("Documents/myfile.dat")
			
			if let data = text.data(using: .utf8) {
				document.fileContent = data
				let _ = await document.save(to: documentURL, for: .forOverwriting)
			}
		}
	}
	
	@MainActor
	func closeDocument() async {
		let _ = await document.close()
	}
	
}

swift

struct EditDocumentView: View {
	@EnvironmentObject var appData: ApplicationData
	@Environment(\.dismiss) var dismiss
	@State private var inputText: String = ""
	
	var body: some View {
		VStack {
			HStack {
				Button("Close") {
					dismiss()
				}
				.padding()
				
				Spacer()
				
				Button("SAve") {
					Task(priority: .high) {
						await appData.saveDocument(text: inputText)
						dismiss()
					}
				}
				.padding()
			}
			GroupBox {
				TextEditor(text: $inputText)
			}
		}
		.task {
			inputText = await appData.openDocument()
		}
		.onDisappear {
			Task(priority: .background) {
				await appData.closeDocument()
			}
		}
	}
}

swift

	@State private var editDocument: Bool = false
	
		VStack {
			Text("My Document")
				.padding()
			Button("Open Document") {
				editDocument = true
			}
				.buttonStyle(.borderedProminent)
				.padding()
		}
		.sheet(isPresented: $editDocument) {
			EditDocumentView()
		}

xml

	<key>NSUbiquitousContainers</key>
	<dict>
		<key>iCloud.com.sugoi-user.SugoiApp</key>
		<dict>
			<key>NSUbiquitousContainerIsDocumentScopePublic</key>
			<true/>
			<key>NSUbiquitousContainerName</key>
			<string>SugoiApp</string>
			<key>NSUbiquitousContainerSupportedFolderLevels</key>
			<string>Any</string>
		</dict>
	</dict>