I have the following code:

import SwiftUI

@main
struct MyApp: App {
    var body: some Scene {
        WindowGroup {
            GeometryReader { geometry in
                LocationPickerView()
                    .frame(maxWidth: geometry.size.width, maxHeight: geometry.size.height)
                    .ignoresSafeArea()
            }
        }
    }
}

My goal is to have my LocationPickerView() take up the entire screen regardless of the orientation of the device. A LocationPickerView() is a custom view I built:

struct LocationView: UIViewRepresentable {
    func makeUIView(context: Context) -> ARView {
        let arView = ARView()

        return arView
    }

    func updateUIView(_ uiView: ARView, context: Context) { }
}

However, I have a problem. The safe area is not being ignored. At first glance, I thought this was because the frame was already set by a "constant" value from geometry.

So, I thought I would flip the order of when I ignore the safe area and when I set the frame. This only resulted in a much weirder configuration. At first, the view does take up the entire screen. However, when I change the device to another orientation, the view stays the original height and width it was without updating, despite using GeometryReader.

What is happening here? I am certain this is valid behavior, but I don't understand why it is and how to fix it. I am trying to make things as simple as possible and thought I would add the frame and safe area options in my main struct, in an attempt to keep that code out of every view.

This feels like an easy fix, but I can't figure it out.

Probably all depends on what you have inside your LocationPickerView.

Simple code like below handles everything without a hitch.

struct ContentView: View {
    var body: some View {
        MyCustomView()
            .ignoresSafeArea()
    }
}

struct MyCustomView: UIViewRepresentable {
    func makeUIView(context: Context) -> some UIView {
        let view = UIView()
        view.backgroundColor = UIColor(.blue)
        return view
    }

    func updateUIView(_ uiView: UIViewType, context: Context) { }
}

I think it has something to do with ARView. I tested your code and it does indeed work. However, it doesn't seem to work with what I have. I will look into it more, but this is kind of odd.

I found a person with the same issue, but no solution: https://www.reddit.com/r/SwiftUI/comments/j5s7tn/how_to_make_arview_fullscreen_uiviewrepresentable/

It to do with GeometryReader which take up the whole View therefore .ignoresSafeArea() is ignore.

@NigelGee I think my situation using ARView is a little bit more complicated than that, unfortunately. Take a look at this post I found:

https://developer.apple.com/forums/thread/665031

@joenaveau Check out Understanding frames and coordinates inside GeometryReader. It might help you understand what happen with it, and then you can work out with the ARView.