ObserverList

An implementation of observable weak collection for Swift. Now you can think less about retain cycles in your applications.

• Usage
• Requirements
• Communication
• Installation
• Author
• License

Usage

If you want to notify some elements about some actions and you don't want to get a retain cycle you can use ObserverList for storing and notifying your elements.

Example №1

typealias FirstClosure = (Int) -> Void
typealias SecondClosure = () -> Void
typealias ThirdClosure = (String, String) -> Void

// MARK: - SomeObserving

struct SomeObserving {

    // MARK: - Properties

    let firstClosure: FirstClosure?
    let secondClosure: SecondClosure?
    let thirdClosure: ThirdClosure?

    // MARK: - Initializers

    init(
        firstClosure: FirstClosure? = nil,
        secondClosure: SecondClosure? = nil,
        thirdClosure: ThirdClosure? = nil
    ) {
        self.firstClosure = firstClosure
        self.secondClosure = secondClosure
        self.thirdClosure = thirdClosure
    }
}

// MARK: MyService

final class MyService {

    // MARK: - Properties

    private let observers = ObserverList<SomeObserving>()

    // MARK: - Useful

    func add(observer: AnyObject, closures: SomeObserving) {
        observers.addObserver(disposable: observer, observer: closures)
    }

    func remove(observer: AnyObject) {
        observers.removeObserver(disposable: observer)
    }

    func someEvent(_ int: Int) {
        observers.forEach { closures in
            closures.firstClosure?(int)
        }
    }

    func someEvent() {
        observers.forEach { closures in
            closures.secondClosure?()
        }
    }

    func someEvent(string1: String, string2: String) {
        observers.forEach { closures in
            closures.thirdClosure?(string1, string2)
        }
    }
}

Example №2

// MARK: - UserLocationPlainObject

struct UserLocationPlainObject {

    // MARK: - Properties

    /// Current user coordinate
    let coordinate: CoordinatesPlainObject

    /// User's heading
    let heading: Double

    /// Current user speed
    let speed: Double
}

/// Services success block for `Obtain` operation
typealias ServiceObtainSuccessBlock<T> = (T) -> Void

// MARK: - UserLocationServiceObservable

final class UserLocationServiceObservable: NSObject {

    // MARK: - Properties

    /// All current user location observers
    private var userLocationObservers = ObserverList<ServiceObtainSuccessBlock<UserLocationPlainObject>>()

    /// CLLocationManager instance
    private let locationManager = CLLocationManager()

    // MARK: - Initializers

    override init() {
        super.init()
        locationManager.delegate = self
        locationManager.startUpdatingLocation()
    }

    // MARK: - Useful

    func add(
        observer: AnyObject,
        onLocationUpdate: @escaping ServiceObtainSuccessBlock<UserLocationPlainObject>
    ) {
        userLocationObservers.addObserverIfNotContains(
            disposable: observer,
            observer: onLocationUpdate
        )
    }

    func remove(observer: AnyObject) {
        userLocationObservers.removeObserver(disposable: observer)
    }

    // MARK: - Private

    private func setup() {
        locationManager.showsBackgroundLocationIndicator = true
        locationManager.allowsBackgroundLocationUpdates = true
    }
}

// MARK: - CLLocationManagerDelegate

extension UserLocationServiceObservable: CLLocationManagerDelegate {

    func locationManager(
        _ manager: CLLocationManager,
        didUpdateLocations locations: [CLLocation]
    ) {
        let userLocation = locations[0]
        let location = UserLocationPlainObject(
            coordinate: .init(userLocation.coordinate),
            heading: userLocation.course,
            speed: max(0, (userLocation.speed * 60 * 60) / 1_000)
        )
        userLocationObservers.forEach { block in
            block(location)
        }
    }
}

Requirements

• iOS 10.0+ / macOS 10.12+ / tvOS 10.0+ / watchOS 3.0+
• Xcode 12.0
• Swift 5

Communication

• If you found a bug, open an issue.
• If you have a feature request, open an issue.
• If you want to contribute, submit a pull request.

Installation

CocoaPods

CocoaPods is a dependency manager for Cocoa projects. You can install it with the following command:

$ gem install cocoapods

To integrate ObsserverList into your Xcode project using CocoaPods, specify it in your Podfile:

use_frameworks!

target "<Your Target Name>" do
    pod "incetro-observer-list"
end

Then, run the following command:

$ pod install

Manually

If you prefer not to use any dependency managers, you can integrate ObserverList into your project manually.

Drag and drop

Just drag and drop ObserverList.swift into your project!

Embedded Framework

• Open up Terminal, cd into your top-level project directory, and run the following command "if" your project is not initialized as a git repository:

  $ git init

• Add ObserverList as a git submodule by running the following command:

  $ git submodule add https://github.com/Incetro/observer-list.git

• Open the new ObserverList folder, and drag the ObserverList.xcodeproj into the Project Navigator of your application's Xcode project.

  It should appear nested underneath your application's blue project icon. Whether it is above or below all the other Xcode groups does not matter.

• Select the ObserverList.xcodeproj in the Project Navigator and verify the deployment target matches that of your application target.

• Next, select your application project in the Project Navigator (blue project icon) to navigate to the target configuration window and select the application target under the "Targets" heading in the sidebar.

• In the tab bar at the top of that window, open the "General" panel.

• Click on the + button under the "Embedded Binaries" section.

• You will see two different ObserverList.xcodeproj folders each with two different versions of the ObserverList.framework nested inside a Products folder.

  It does not matter which Products folder you choose from, but it does matter whether you choose the top or bottom ObserverList.framework.

• Select the top ObserverList.framework for iOS and the bottom one for OS X.

  You can verify which one you selected by inspecting the build log for your project. The build target for Nio will be listed as either ObserverList iOS, ObserverList macOS, ObserverList tvOS or ObserverList watchOS.

• And that's it!

  The ObserverList.framework is automagically added as a target dependency, linked framework and embedded framework in a copy files build phase which is all you need to build on the simulator and a device.

Author

incetro, incetro@ya.ru

License

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