Using UIViewController via the SwiftUI Environment

UIViewController+SwiftUI.swift

struct ViewControllerHolder {
	weak var value: UIViewController?
	init(_ value: UIViewController?) {
		self.value = value
	}
}

struct ViewControllerKey: EnvironmentKey {
	static var defaultValue: ViewControllerHolder { return ViewControllerHolder(UIApplication.shared.windows.first?.rootViewController ) }
}

extension EnvironmentValues {
	var viewController: ViewControllerHolder {
		get { return self[ViewControllerKey.self] }
		set { self[ViewControllerKey.self] = newValue }
	}
}

extension UIViewController {
	func present<Content: View>(presentationStyle: UIModalPresentationStyle = .automatic, transitionStyle: UIModalTransitionStyle = .coverVertical, animated: Bool = true, completion: @escaping () -> Void = {}, @ViewBuilder builder: () -> Content) {
		let toPresent = UIHostingController(rootView: AnyView(EmptyView()))
		toPresent.modalPresentationStyle = presentationStyle
		toPresent.rootView = AnyView(
			builder()
				.environment(\.viewController, ViewControllerHolder(toPresent))
		)
		if presentationStyle == .overCurrentContext {
			toPresent.view.backgroundColor = .clear
		}
		self.present(toPresent, animated: animated, completion: completion)
	}
}

Thanks for this! I have a couple of questions

Is there a way to make the modal only as big as the content you put in it? I don’t want the white box that appears when using .formSheet/pageSheet. (I know I can just set toPresent.view.backgroundColor = .clear) preferredContentSize seems like an option but haven’t had a chance to test

Also when I tried to add a button to the body of ModalContentView to dismiss (experimenting with full screen), the button appeared behind the content, not above it like I expected given its a VStack. I can’t therefore see how to dismiss full screen

@Environment(\.viewController) private var viewControllerHolder: ViewControllerHolder?
private var viewController: UIViewController? {
   self.viewControllerHolder?.value
}

with this code I'm getting error like
Key path value type 'ViewControllerHolder' cannot be converted to contextual type 'ViewControllerHolder?

@Sadmansamee

@Environment(\.viewController) private var viewControllerHolder: ViewControllerHolder?
private var viewController: UIViewController? {
   self.viewControllerHolder?.value
}

with this code I'm getting error like

Key path value type 'ViewControllerHolder' cannot be converted to contextual type 'ViewControllerHolder?

Don't have time to test this but maybe try:

@Environment(\.viewController) private var viewControllerHolder: ViewControllerHolder
private var viewController: UIViewController? {
    self.viewControllerHolder.value
}

Reading the gist, Line 14 defines viewController to return a non-optional ViewControllerHolder so I'm guessing that's the issue you're running into.

and how to dismiss it

its support for RTL?

Using UIViewControllerRepresentable to manage the make/update lifetime will fix the leak.