marty-suzuki / noticeobservekit

NoticeObserveKit is type-safe NotificationCenter wrapper.

NoticeObserveKit

NoticeObserveKit is type-safe NotificationCenter wrapper.

Swift Concurrency (since macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0)

Task {
    // .keyboardWillShow is a static property.
    for try await keyboardInfo in NotificationCenter.default.nok.notifications(named: .keyboardWillShow) { 
        // In this case, keyboardInfo is UIKeyboardInfo type.
        // It is inferred from a generic parameter of Notice.Name<Value>.
        print(keyboardInfo)
    }
}

Combine (since macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0)

// .keyboardWillShow is a static property.
NotificationCenter.default.nok.publisher(for: .keyboardWillShow)
    .sink(
        receiveCompletion: { _ in },
        receiveValue: { keyboardInfo in
            // In this case, keyboardInfo is UIKeyboardInfo type.
            // It is inferred from a generic parameter of Notice.Name<Value>.
            print(keyboardInfo)
        }
    )
    .store(in: &cancellables)

NoticeObserveKit original

// .keyboardWillShow is a static property.
NotificationCenter.default.nok.observe(name: .keyboardWillShow) { keyboardInfo in
    // In this case, keyboardInfo is UIKeyboardInfo type.
    // It is inferred from a generic parameter of Notice.Name<Value>.
    print(keyboardInfo)
}
// pool is Notice.ObserverPool.
// If pool is released, Notice.Observes are automatically removed.
.invalidated(by: pool)

Usage

First of all, you need to implement Notice.Name<T> like this. T is type of value in notification.userInfo.

extension Notice.Names {
    static let keyboardWillShow = Notice.Name<UIKeyboardInfo>(
        UIResponder.keyboardWillShowNotification
    ) { userInfo in
        // Implementing decode is only required if you want to use an already defined Notification.Name (e.g. UIResponder.keyboardWillShowNotification).
        guard
            let frame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue,
            let duration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? TimeInterval,
            let curve = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? UInt
        else {
            throw DecodeError()
        }

        return UIKeyboardInfo(
            frame: frame,
            animationDuration: duration,
            animationCurve: UIViewAnimationOptions(rawValue: curve)
        )
    }
}

Customization

If you can post custom Notification like this.

extension Notice.Names {
    // If you define your own custom Notification.Name, no implementation of decode is required.
    static let navigationControllerDidShow = Notice.Name<NavigationControllerContent>(name: "navigationControllerDidShow")
}

let content = NavigationControllerContent(viewController: viewController, animated: animated)
NotificationCenter.default.nok.post(name: .navigationControllerDidShow, value: content)

You can invalidate manually like this.

let observer = NotificationCenter.default.nok.observe(name: .keyboardWillShow) { keyboardInfo in
    print(keyboardInfo)
}
observer.invalidate()

Sample

import UIKit
import NoticeObserveKit

class ViewController: UIViewController {
    private let searchBar = UISearchBar(frame: .zero)
    private lazy var keyboardNotificationTasks: [Task<Void, Error>] = [
        Task {
            for try await value in NotificationCenter.default.nok.notifications(named: .keyboardWillShow) {
                print("UIKeyboard will show = \(value)")
            }
        },
        Task {
            for try await value in NotificationCenter.default.nok.notifications(named: .keyboardWillHide) {
                print("UIKeyboard will hide = \(value)")
            }
        }
    ]

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        navigationItem.titleView = searchBar

        configureObservers()
    }

    private func configureObservers() {
        _ = keyboardNotificationTasks
    }
}

Requirements

• Swift 5
• Xcode 15.0 or greater
• iOS 10.0 or greater
• tvOS 10.0 or greater
• macOS 10.10 or greater
• watchOS 3.0 or greater

Installation

CocoaPods

NoticeObserveKit is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "NoticeObserveKit"

Carthage

If you’re using Carthage, simply add NoticeObserveKit to your Cartfile:

github "marty-suzuki/NoticeObserveKit"

Make sure to add NoticeObserveKit.framework to "Linked Frameworks and Libraries" and "copy-frameworks" Build Phases.

Author

marty-suzuki, [email protected]

License

NoticeObserveKit is available under the MIT license. See the LICENSE file for more info.

noticeobservekit's Issues

Notifications that doesn't contain a userInfo dictionary

Consider handling such notifications. An example is UserDefaults .didChangeNotification (documentation)

Observe callback does not contain posted object, only contain userInfo.

version: 0.12

public func observe<Value: NoticeUserInfoDecodable>(name: Notice.Name<Value>,
                                                        object: Any? = nil,
                                                        queue: OperationQueue? = nil,
                                                        using: @escaping (Value) -> Void) -> Notice.Observer {
        let observer = center.addObserver(forName: name.raw, object: object, queue: queue) { notification in
            guard
                let userInfo = notification.userInfo,
                let value = Value(info: userInfo)
                else {
                    return
            }
            using(value)
        }
        return Notice.Observer(center: center, raw: observer)

Here is the implementation in pods.

received object is abandoned, can not get this from outside.