Cannot place SwiftUI view outside the SafeArea when embedded in UIHostingController

Question

I have a simple SwiftUI view that contains 3 text elements:

struct ImageDescriptionView: View {
    var title: String?
    var imageDescription: String?
    var copyright: String?

    var body: some View {
        VStack(alignment: .leading) {
        
            if let title = title {
                Text(title)
                    .fontWeight(.bold)
                    .foregroundColor(.white)
                    .frame(maxWidth: .infinity, alignment: .leading)
            }
        
            if let imageDescription = imageDescription {
                Text(imageDescription)
                    .foregroundColor(.white)
                    .fontWeight(.medium)
                    .frame(maxWidth: .infinity, alignment: .leading)
            }
        
            if let copyright = copyright {
                Text(copyright)
                    .font(.body)
                    .foregroundColor(.white)
                    .frame(maxWidth: .infinity, alignment: .leading)
            }
        
        }
        .background(
            Color.blue
        )
    }
}

The SwiftUI View is embedded within a UIHostingController:

class ViewController: UIViewController {

    private var hostingController = UIHostingController(rootView: ImageDescriptionView(title: "25. November 2021", imageDescription: "Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.", copyright: "Bild © Unknown"))

    override func viewDidLoad() {
        super.viewDidLoad()
        setUpHC()
    }

    private func setUpHC() {
        hostingController.view.backgroundColor = .red
    
        view.addSubview(hostingController.view)
        hostingController.view.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            hostingController.view.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            hostingController.view.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            hostingController.view.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
        addChild(hostingController)
        hostingController.didMove(toParent: self)
    }

}

The result looks like this:

The UIHostingController is always bigger than the view. Also, it will always make the SwiftUI view respect the safe area (which in my case, I do not want)

The look I want:

(please don't comment the usability of the home indicator, that's not the case here)

What's the problem with UIHostingController? I tried setting .edgesIgnoreSafeArea(.all) on all Views within ImageDescriptionView, did not help.

Answer 1

As Alex mentioned in a comment to my question, it seems like Apple fixed it.

Xcode 14.3, iOS 16 Simulator

Answer 2

On the UIHostingControllers property try the following

viewController._disableSafeArea = true

that should do the trick.

Answer 3

I came across the same issue. You have to ignore the safe area at the SwiftUI view level.

var body: some View {
    VStack(alignment: .leading) {
        ...
    }
    .ignoresSafeArea(edges: .all) // ignore all safe area insets
}

Answer 4

Got a discussion here, and the detail here

extension UIHostingController {
    convenience public init(rootView: Content, ignoreSafeArea: Bool) {
        self.init(rootView: rootView)
        
        if ignoreSafeArea {
            disableSafeArea()
        }
    }
    
    func disableSafeArea() {
        guard let viewClass = object_getClass(view) else { return }
        
        let viewSubclassName = String(cString: class_getName(viewClass)).appending("_IgnoreSafeArea")
        if let viewSubclass = NSClassFromString(viewSubclassName) {
            object_setClass(view, viewSubclass)
        }
        else {
            guard let viewClassNameUtf8 = (viewSubclassName as NSString).utf8String else { return }
            guard let viewSubclass = objc_allocateClassPair(viewClass, viewClassNameUtf8, 0) else { return }
            
            if let method = class_getInstanceMethod(UIView.self, #selector(getter: UIView.safeAreaInsets)) {
                let safeAreaInsets: @convention(block) (AnyObject) -> UIEdgeInsets = { _ in
                    return .zero
                }
                class_addMethod(viewSubclass, #selector(getter: UIView.safeAreaInsets), imp_implementationWithBlock(safeAreaInsets), method_getTypeEncoding(method))
            }
            
            objc_registerClassPair(viewSubclass)
            object_setClass(view, viewSubclass)
        }
    }
}

Answer 5

Happened to me too. When I aligned my view with the frame it worked, but to make it work with autolayout I had to consider the height of the safe area to make it work with UIHostingController, even though I didn't have to do that with a standard view.

code:

hostingVC.view.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: view.safeAreaInsets.bottom).isActive = true

Answer 6

In my case, I had a circle view inside UIHostingController and its background automatically resized when it close to safe area. I could be able to avoid it by setting autoresizesSubviews to false.

UIHostingController.view.autoresizesSubview = false

Answer 7

iOS 16.4 Update

There's now an official API in iOS 16.4 for the previously private API method:

viewController.safeAreaRegions = SafeAreaRegions()

The SafeAreaRegions() initialiser returns an empty collection. Default value of .safeAreaRegions is .all.

Backwards compatible answer

If you want to be backwards compatible and support iOS 13+, there is a workaround:

let controller = UIHostingController(rootView: buttonView)
let window = UIApplication.shared.windows.first(where: \.isKeyWindow)
let inverseSafeAreaInset = window?.safeAreaInsets.bottom ?? 0
controller.additionalSafeAreaInsets = UIEdgeInsets(top: 0, left: 0, bottom: -inverseSafeAreaInset, right: 0)

Note you can get the inverse offset from the parent view / VC in multiple ways. e.g. view.safeAreaInsets works once the view has been laid out, however the window approach works for all contexts.