suspend-view-controller-sample

iOS Tech Talk【みてね x Mirrativ】
Swift Concurrencyを利用したUIViewController表示の排他制御の実装
https://mirrativ.connpass.com/event/240385/

sample code: https://github.com/to4iki/suspend-view-controller-sample

Transcript

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   ޙଓͷը໘දࣔ͸࣮ߦ͞Εͳ͍ func tapButton() { let coverVC1 = CoverViewController(rootView: .init(item: .red)) present(coverVC1, animated: true) let coverVC2 = CoverViewController(rootView: .init(item: .yellow)) present(coverVC2, animated: true) }
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11. දࣔதͷ଴ػΛࣔ͢ܕͷఆٛ TVTQFOE͢Δը໘Λࣔ͢QSPUPDPM @MainActor protocol SuspendableViewControllerProtocol: AnyObject { var didDisappearHandler: (() -> Void)? { get set } } typealias SuspendableViewController = UIViewController & SuspendableViewControllerProtocol
12. දࣔதͷ଴ػΛࣔ͢ܕͷఆٛ TVTQFOE͢Δը໘ͷ࣮૷ class CoverViewController: UIHostingController<CoverView>, SuspendableViewControllerProtocol { var didDisappearHandler: (() -> Void)? override func viewDidDisappear(_ animated: Bool) { super.viewDidDisappear(animated) didDisappearHandler?() } }
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    Λར༻͠ఆٛ͢Δ extension UIViewController { func presentAsync(_ viewController: SuspendableViewController, animated: Bool, completion: (() -> Void)? = nil) async { present(viewController, animated: animated, completion: completion) await withCheckedContinuation { continuation in viewController.didDisappearHandler = { continuation.resume() } } } }
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16. 5BTL TZODίʔυ͔ΒBTZODίʔυΛݺͼग़͢ func tapButton() { Task { let coverVC1 = CoverViewController(rootView: .init(item: .red)) await presentAsync(coverVC1, animated: true) let coverVC2 = CoverViewController(rootView: .init(item: .yellow)) await presentAsync(coverVC2, animated: true) } }
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19. 5BTLDBODFM 5BTLΠϯελϯεΛอ࣋͠ɺΩϟϯηϧΛݺͼग़͢ var task: Task<Void, Never>? func tapButton() { DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in self?.task?.cancel() } self.task = Task { let coverVC1 = CoverViewController(rootView: .init(item: .red)) await presentAsync(coverVC1, animated: true) let coverVC2 = CoverViewController(rootView: .init(item: .yellow)) await presentAsync(coverVC2, animated: true) } }
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24. 5BTLJT$BODFMMFE ݺͼग़͠ଆ func tapButton() { DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in self?.task?.cancel() } self.task = Task { let coverVC1 = CoverViewController(rootView: .init(item: .red)) await presentAsync(coverVC1, animated: true) let coverVC2 = CoverViewController(rootView: .init(item: .yellow)) await presentAsync(coverVC2, animated: true) } }
25. 5BTLJT$BODFMMFE ޙଓͷը໘දࣔ͸࣮ߦ͞Εͳ͍
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27. 5BTLDIFDL$BODFMMBUJPO ݺͼग़͠ଆͰͷΩϟϯηϧ࣌ͷϋϯυϦϯά func tapButton() { DispatchQueue.main.asyncAfter(deadline: .now() + 3) { [weak self] in self?.task?.cancel() } self.task = Task { do { let coverVC1 = CoverViewController(rootView: .init(item: .red)) try await presentAsync(coverVC1, animated: true) let coverVC2 = CoverViewController(rootView: .init(item: .yellow)) try await presentAsync(coverVC2, animated: true) } catch { // CancellationError dismiss(animated: true) } } }
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30. XJUI5BTL$BODFMMBUJPO)BOEMFS දࣔதͷը໘Λด͡Δ
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