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Merge pull request #677 from ibrahimkteish/view-controller-life-cycle
Add the ability to observe UIViewController life cycle using signals
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,154 @@ | ||
| // | ||
| // ViewControllerLifeCycle.swift | ||
| // Bond-iOS | ||
| // | ||
| // Created by Ibrahim Koteish on 21/03/2020. | ||
| // Copyright © 2020 Swift Bond. All rights reserved. | ||
| // | ||
|
|
||
| import Foundation | ||
| import UIKit | ||
| import ReactiveKit | ||
|
|
||
| public enum LifecycleEvent { | ||
| case viewDidLoad | ||
| case viewWillAppear | ||
| case viewDidAppear | ||
| case viewWillDisappear | ||
| case viewDidDisappear | ||
| case viewDidLayoutSubviews | ||
| case viewWillLayoutSubviews | ||
| } | ||
|
|
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| /// Observe UIViewController life cycle events | ||
| public final class ViewControllerLifecycle { | ||
|
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| private let wrapperViewController: WrapperViewController | ||
|
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| public var lifecycleEvents: Signal<LifecycleEvent, Never> { | ||
| self.wrapperViewController.lifecycleEvents | ||
| } | ||
|
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| public func lifecycleEvent(_ event: LifecycleEvent) -> Signal<Void, Never> { | ||
| self.wrapperViewController.lifecycleEvent(event) | ||
| } | ||
|
|
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| public init(viewController: UIViewController) { | ||
| self.wrapperViewController = WrapperViewController() | ||
| if viewController.isViewLoaded { | ||
| self.addAsChildViewController(viewController) | ||
| } else { | ||
| viewController | ||
| .reactive | ||
| .keyPath(\.view, startWithCurrentValue: false) | ||
| .prefix(maxLength: 1) | ||
| .bind(to: viewController) { (viewController, _) in | ||
| self.addAsChildViewController(viewController) | ||
| } | ||
| } | ||
| } | ||
|
|
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| private func addAsChildViewController(_ viewController: UIViewController) { | ||
|
|
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| viewController.addChild(self.wrapperViewController) | ||
| viewController.view.addSubview(self.wrapperViewController.view) | ||
| self.wrapperViewController.view.frame = .zero | ||
| self.wrapperViewController.view.autoresizingMask = [] | ||
| self.wrapperViewController.didMove(toParent: viewController) | ||
| } | ||
| } | ||
|
|
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| private extension ViewControllerLifecycle { | ||
|
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| final class WrapperViewController: UIViewController { | ||
|
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|
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| deinit { | ||
| _lifecycleEvent.send(completion: .finished) | ||
| } | ||
|
|
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| private let _lifecycleEvent = PassthroughSubject<LifecycleEvent, Never>() | ||
|
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| public var lifecycleEvents: Signal<LifecycleEvent, Never> { | ||
| var signal = _lifecycleEvent.toSignal() | ||
| if isViewLoaded { | ||
| signal = signal.prepend(.viewDidLoad) | ||
| } | ||
| return signal | ||
| } | ||
|
|
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| public func lifecycleEvent(_ event: LifecycleEvent) -> Signal<Void, Never> { | ||
| return lifecycleEvents.filter { $0 == event }.eraseType() | ||
| } | ||
|
|
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| //MARK: - Overrides | ||
| override func viewDidLoad() { | ||
| super.viewDidLoad() | ||
| _lifecycleEvent.send(.viewDidLoad) | ||
| } | ||
|
|
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| override func viewWillAppear(_ animated: Bool) { | ||
| super.viewWillAppear(animated) | ||
| _lifecycleEvent.send(.viewWillAppear) | ||
| } | ||
|
|
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| override func viewDidAppear(_ animated: Bool) { | ||
| super.viewDidAppear(animated) | ||
| _lifecycleEvent.send(.viewDidAppear) | ||
| } | ||
|
|
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| override func viewWillDisappear(_ animated: Bool) { | ||
| super.viewWillDisappear(animated) | ||
| _lifecycleEvent.send(.viewWillDisappear) | ||
| } | ||
|
|
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| override func viewDidDisappear(_ animated: Bool) { | ||
| super.viewDidDisappear(animated) | ||
| _lifecycleEvent.send(.viewDidDisappear) | ||
| } | ||
|
|
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| override func viewWillLayoutSubviews() { | ||
| super.viewWillLayoutSubviews() | ||
| _lifecycleEvent.send(.viewWillLayoutSubviews) | ||
| } | ||
|
|
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| override func viewDidLayoutSubviews() { | ||
| super.viewDidLayoutSubviews() | ||
| _lifecycleEvent.send(.viewDidLayoutSubviews) | ||
| } | ||
| } | ||
| } | ||
|
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| public protocol ViewControllerLifecycleProvider: class { | ||
| var viewControllerLifecycle: ViewControllerLifecycle { get } | ||
| } | ||
|
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| extension UIViewController: ViewControllerLifecycleProvider { | ||
|
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| private struct AssociatedKeys { | ||
| static var viewControllerLifeCycleKey = "viewControllerLifeCycleKey" | ||
| } | ||
|
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| public var viewControllerLifecycle: ViewControllerLifecycle { | ||
| if let lifeCycle = objc_getAssociatedObject(self, &AssociatedKeys.viewControllerLifeCycleKey) { | ||
| return lifeCycle as! ViewControllerLifecycle | ||
| } else { | ||
| let lifeCycle = ViewControllerLifecycle(viewController: self) | ||
| objc_setAssociatedObject( | ||
| self, | ||
| &AssociatedKeys.viewControllerLifeCycleKey, | ||
| lifeCycle, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC) | ||
| return lifeCycle | ||
| } | ||
| } | ||
| } | ||
|
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| extension ReactiveExtensions where Base: ViewControllerLifecycleProvider { | ||
| public var lifecycleEvents: Signal<LifecycleEvent, Never> { | ||
| self.base.viewControllerLifecycle.lifecycleEvents | ||
| } | ||
|
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| public func lifecycleEvent(_ event: LifecycleEvent) -> Signal<Void, Never> { | ||
| self.base.viewControllerLifecycle.lifecycleEvent(event) | ||
| } | ||
| } |