Nivelir

In multi-module projects, you can pass Screen factories through DI by erasing their types. This prevents module leakage while maintaining navigation capabilities.

• Screen/eraseToAnyScreen(): Erases the type but preserves the container type (e.g., AnyTabsScreen or AnyStackScreen), allowing for tab switching or stack changes.
• Screen/eraseToAnyModalScreen(): Erases the container type to UIViewController, ensuring the container type does not extend beyond the module boundary.

You can also share ScreenRoute objects (like ScreenWindowRoute) between modules to define complex navigation paths that can be executed by a central navigator.

// Erasing a factory for DI
struct Screens {
    func homeScreen() -> AnyTabsScreen {
        HomeScreen(services: services, screens: self).eraseToAnyScreen()
    }
}

// Executing a shared route from DI
let screens: Screens
let navigator = ScreenNavigator()
navigator.navigate(to: screens.showRoomListRoute())

Nivelir uses a Screen protocol to define view controllers and a ScreenNavigator to execute navigation commands.

1. Define a Screen: Implement the Screen protocol. The build(navigator:) method is responsible for returning the UIViewController instance.
2. Execute Navigation: Use a ScreenNavigator instance and its navigate method. Inside the closure, use the provided route to chain commands like .top(), .popToRoot(), .push(), and .present().

// 1. Define your ViewController
class SomeViewController: UIViewController {
    let color: UIColor
    init(color: UIColor) { 
        self.color = color
        super.init(nibName: nil, bundle: nil) 
    }
    required init?(coder: NSCoder) { fatalError() }
    override func viewDidLoad() { super.viewDidLoad(); view.backgroundColor = color }
}

// 2. Implement the Screen protocol
struct SomeScreen: Screen {
    let color: UIColor
    func build(navigator: ScreenNavigator) -> UIViewController {
        SomeViewController(color: color)
    }
}

// 3. Navigate
let navigator = ScreenNavigator()

navigator.navigate { route in
    route
        .top(.stack)
        .popToRoot()
        .push(SomeScreen(color: .red))
        .push(SomeScreen(color: .green)) { route in
            route.present(SomeScreen(color: .blue))
        }
}

Nivelir uses a DSL to define screens and navigate between them. To use it, follow these three steps:

1. Define your View Controller: Create a standard UIViewController (or UIView based controller) that handles the UI logic.
2. Implement the Screen protocol: Create a struct that conforms to Screen. This struct acts as a builder that takes parameters and returns the actual UIViewController via the build(navigator:) method.
3. Use ScreenNavigator to navigate: Initialize a ScreenNavigator and use the navigate method to chain navigation actions like push, popToRoot, and present.

// 1. The View Controller
class SomeViewController: UIViewController {
    let color: UIColor
    init(color: UIColor) { 
        self.color = color
        super.init(nibName: nil, bundle: nil) 
    }
    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = color
    }
}

// 2. The Screen implementation
struct SomeScreen: Screen {
    let color: UIColor
    func build(navigator: ScreenNavigator) -> UIViewController {
        SomeViewController(color: color)
    }
}

// 3. Navigation
let navigator = ScreenNavigator()
navigator.navigate { route in
    route
        .top(.stack)
        .popToRoot()
        .push(SomeScreen(color: .red))
        .push(SomeScreen(color: .green)) { route in
            route.present(SomeScreen(color: .blue))
        }
}

Nivelir supports custom animations for several navigation types:

• Root replacement: Use ScreenRootCustomAnimation via route.setRoot(to:animation:).
• Stack changes: Use ScreenStackCustomAnimation via route.replace(with:animation:) or route.push(_:animation:).
• Tab switching: Use ScreenTabCustomAnimation.
• Modal presentation: Use route.present(_:) combined with Screen/withModalTransitioningDelegate(_:) to pass a UIViewControllerTransitioningDelegate.

Prebuilt animations like .crossDissolve can be passed to the animation parameter.

// Replace root with cross-dissolve
navigator.navigate { route in
    route.setRoot(to: screens.homeScreen(), animation: .crossDissolve)
}

// Custom modal transition
navigator.navigate(from: container) { route in
    route.present(
        screens
            .floatingActionSheetScreen()
            .withModalTransitioningDelegate(CardModalTransitionAnimator())
    )
}