Compilable Needle dependency injection framework example

README.md

Compilable Needle RootComponent example

Documentation of the Needle dependency injection framework sucks, and most of articles teaching you how to use it are outdated. That's the reason why it's really hard to write even a minimal-working version of the code that compiles.

This is a simple example of RootComponent that compiles successfully. Based on a code from an article "Dependency Injection with Needle", but modified to make it work.

Bonus: How to configure Xcode

1. Go to your target
2. Build Phases
3. Click "+" button
4. New Run Script Phase

Move created build phase to very top of your list of build phases.

It's important to make sure "Shell" field containts /bin/sh, and into a field below add following bash script:

export SOURCEKIT_LOGGING=0 && /opt/homebrew/bin/needle generate $SRCROOT/$TARGETNAME/NeedleGenerated.swift $SRCROOT/$TARGETNAME

Note that a path to the needle binary should be absolute. You can locate this path with whereis needle command.

One more thing to do:

1. Go to your target
2. Build Settings
3. Type "sandboxing" into a search field
4. Set "No" to "User Script Sandboxing" build option

With user script sandboxing enabled Xcode won't allow needle binary to read your project files and modify them.

After you try to build a project NeedleGenerated.swift file will be generated. Add it to a project via menu bar:

1. File
2. Add Files to $TARGETNAME...

RootComponent.swift

import NeedleFoundation
import UIKit

final class RootComponent: BootstrapComponent {
    public var userInfo: UserDataParseable {
        return shared { UserData() }
    }

    public var detailComponent: DetailComponent {
        return DetailComponent(parent: self)
    }

    public var rootViewController: UIViewController {
        return RootViewController(detailBuilder: detailComponent)
    }
}

final class RootViewController: UIViewController {
    public let detailBuilder: DetailBuilder
    public let detailButton = UIButton()

    init(detailBuilder: DetailBuilder) {
        self.detailBuilder = detailBuilder
        super.init(nibName: nil, bundle: nil)
    }

    @available(*, unavailable)
    required init?(coder _: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .black
        configureButton()
    }

    public func configureButton() {
        view.addSubview(detailButton)

        var buttonConfiguration = UIButton.Configuration.bordered()
        buttonConfiguration.title = "Go to Details"
        buttonConfiguration.baseBackgroundColor = .white

        detailButton.configuration = buttonConfiguration

        detailButton.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            detailButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            detailButton.centerYAnchor.constraint(equalTo: view.centerYAnchor),
        ])

        detailButton.addTarget(self, action: #selector(detailButtonTap), for: .touchUpInside)
    }

    @objc
    public func detailButtonTap() {
        present(detailBuilder.detailViewController, animated: true)
    }
}

protocol UserDataParseable {
    var data: String? { get }
}

final class UserData: UserDataParseable {
    public var data: String? = "Ana Maia"
}

protocol DetailDependency: Dependency {
    var userInfo: UserDataParseable { get }
}

protocol DetailBuilder {
    var detailViewController: UIViewController { get }
}

final class DetailComponent: Component<DetailDependency>, DetailBuilder {
    public var detailViewController: UIViewController {
        return DetailViewController(userData: dependency.userInfo)
    }
}

final class DetailViewController: UIViewController {
    public var titleLabel = UILabel()

    init(userData: UserDataParseable) {
        super.init(nibName: nil, bundle: nil)
        titleLabel.text = userData.data
    }

    @available(*, unavailable)
    required init?(coder _: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        configureTitleLabel()
    }

    public func configureTitleLabel() {
        view.addSubview(titleLabel)

        titleLabel.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            titleLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            titleLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor),
        ])
    }
}