Custom size popover in iOS SwiftUI

WithPopover.swift

// -- Usage

struct Content: View {
    @State var open = false
    @State var popoverSize = CGSize(width: 300, height: 300)
    
    var body: some View {
        WithPopover(
            showPopover: $open,
            popoverSize: popoverSize,
            content: {
                Button(action: { self.open.toggle() }) {
                    Text("Tap me")
                }
        },
            popoverContent: {
                VStack {
                    Button(action: { self.popoverSize = CGSize(width: 300, height: 600)}) {
                        Text("Increase size")
                    }
                    Button(action: { self.open = false}) {
                        Text("Close")
                    }
                }
        })
    }
}


// -- Source

struct WithPopover<Content: View, PopoverContent: View>: View {
    
    @Binding var showPopover: Bool
    var popoverSize: CGSize? = nil
    let content: () -> Content
    let popoverContent: () -> PopoverContent
    
    var body: some View {
        content()
        .background(
            Wrapper(showPopover: $showPopover, popoverSize: popoverSize, popoverContent: popoverContent)
                .frame(maxWidth: .infinity, maxHeight: .infinity)
        )
    }
    
    struct Wrapper<PopoverContent: View> : UIViewControllerRepresentable {
        
        @Binding var showPopover: Bool
        let popoverSize: CGSize?
        let popoverContent: () -> PopoverContent
        
        func makeUIViewController(context: UIViewControllerRepresentableContext<Wrapper<PopoverContent>>) -> WrapperViewController<PopoverContent> {
            return WrapperViewController(
                popoverSize: popoverSize,
                popoverContent: popoverContent) {
                    self.showPopover = false
            }
        }
        
        func updateUIViewController(_ uiViewController: WrapperViewController<PopoverContent>,
                                    context: UIViewControllerRepresentableContext<Wrapper<PopoverContent>>) {
            uiViewController.updateSize(popoverSize)

            if showPopover {
                uiViewController.showPopover()
            }
            else {
                uiViewController.hidePopover()
            }
        }
    }
    
    class WrapperViewController<PopoverContent: View>: UIViewController, UIPopoverPresentationControllerDelegate {
        
        var popoverSize: CGSize?
        let popoverContent: () -> PopoverContent
        let onDismiss: () -> Void
        
        var popoverVC: UIViewController?

        required init?(coder: NSCoder) { fatalError("") }
        init(popoverSize: CGSize?,
             popoverContent: @escaping () -> PopoverContent,
             onDismiss: @escaping() -> Void) {
            self.popoverSize = popoverSize
            self.popoverContent = popoverContent
            self.onDismiss = onDismiss
            super.init(nibName: nil, bundle: nil)
        }
        
        override func viewDidLoad() {
            super.viewDidLoad()
        }
        
        func showPopover() {
            guard popoverVC == nil else { return }
            let vc = UIHostingController(rootView: popoverContent())
            if let size = popoverSize { vc.preferredContentSize = size }
            vc.modalPresentationStyle = UIModalPresentationStyle.popover
            if let popover = vc.popoverPresentationController {
                popover.sourceView = view
                popover.delegate = self
            }
            popoverVC = vc
            self.present(vc, animated: true, completion: nil)
        }
        
        func hidePopover() {
            guard let vc = popoverVC, !vc.isBeingDismissed else { return }
            vc.dismiss(animated: true, completion: nil)
            popoverVC = nil
        }
        
        func presentationControllerWillDismiss(_ presentationController: UIPresentationController) {
            popoverVC = nil
            self.onDismiss()
        }
        
        func updateSize(_ size: CGSize?) {
            self.popoverSize = size
            if let vc = popoverVC, let size = size {
                vc.preferredContentSize = size
            }
        }
    }
}

it's not working as popOver it's showing as sheet

if you add the following func you'll get the popover on iPhone as well

func adaptivePresentationStyle(for controller: UIPresentationController) -> UIModalPresentationStyle {
 return .none // this is what forces popovers on iPhone 
}

@wassupdoc Where should that func to be added ?

@ccwasden If the popovercontent is getting modiifed while using it, it doesn't reflect in the view

Ignore my above comment. I figured that out :)

Brilliant mate -- a real help to SwiftUI folks :-)

@dmallass - I'm having the same issue where the view isn't reflecting the underlying state changes. happen to remember what was causing that issue for you?

Yes, this didn't work on iPhone simulators on 15.2, but adding the function above (by @wassupdoc ) is what did it. Add it to the class, WrapperViewController.

@dmallass - I'm having the same issue where the view isn't reflecting the underlying state changes. happen to remember what was causing that issue for you?

I have solved this issue by adding the following code to func updateUIViewController after the if else pair:

if let hostingController = uiViewController.popoverVC as? UIHostingController<PopoverContent> {
    hostingController.rootView = popoverContent()
}