Chapter 4--Hosting ViewControllers In SwiftUI

📚 Official Books SwiftUI by Tutorials
1

I am using the code in the book to host a ViewController in a SwiftUI project. I use instead of “ViewController”, “DocumentSaveViewController” and my StoryBoard ID is “DocumentSave”. Compiles okay but when I hit the Text(“Save File”) I get a Thread 1: signal SIGABRT and in the DocumentSaveViewController’s ViewControllerRepresentation struct :

struct ViewControllerRepresentation: UIViewControllerRepresentable {

func makeUIViewController(
context: UIViewControllerRepresentableContext
) → DocumentSaveViewController {
UIStoryboard(name: “Main”, bundle: nil)
.instantiateViewController(withIdentifier: “DocumentSave”)
as! DocumentSaveViewController // this is the line where the program stops
}

func updateUIViewController(_ uiViewController: DocumentSaveViewController,
context: UIViewControllerRepresentableContext
) {
}
}

This struct is outside the DocumentSaveViewController class. Is this because I don’t use “ViewController”?

2

hi Garrett!

The context argument should be

context: UIViewControllerRepresentableContext<ViewControllerRepresentation>)

The struct in the angle brackets is whatever you named your UIViewControllerRepresentable struct. In this case, you kept it as ViewControllerRepresentation.

Strange, my code won’t compile without it.

3

Since it crashes in this line:

UIStoryboard(name: “Main”, bundle: nil)
    .instantiateViewController(withIdentifier: “DocumentSave”)
    as! DocumentSaveViewController

I would say that probably it’s because it can’t find a view controller with the DocumentSave identifier, or it cannot be cast to DocumentSaveViewController - I would double check both cases. Have you updated the “custom class” of the view controller in the storyboard?