SwiftUI + UIKit project causes crashes

[amsam0]

Hi, we have a UIKit project that we are currently working on migrating to SwiftUI. The default view is SwiftUI, and we use a UIHostingController to display it. I’ve added inject into the SwiftUI view, and editing already added elements works fine (like changing text). However, if I add a new element, it crashes the app with Thread 1: EXC_BAD_ACCESS (code=1, address=…). Is there any way I can fix this? I’ve tried using Inject.ViewControllerHost on the UIHostingController, and also using Inject.ViewControllerHost without having inject in the SwiftUI part, but neither helped.

Our project is open source, and I can give you a link to the branch with the SwiftUI stuff if needed. (I haven’t pushed adding Inject yet.) It’s a pretty complex project, and uses libraries written in Objective-C and Rust, so it might take a little while to setup.

[johnno1962]

Hi, Can you post an image of the stack trace or the link to the branch please?

[amsam0]

Here’s the branch: https://github.com/SideStore/SideStore/tree/naturecodevoid/swiftui-improvements As I said, it is a decently complex project and setup might take a while (you will need Rust installed, and it will take 5-10 minutes to compile the rust dependencies). There are some compilation instructions: https://github.com/SideStore/SideStore/tree/naturecodevoid/swiftui-improvements#compilation-instructions (they are slightly outdated, you should be able to skip some of the steps to run on simulator, and I’m not sure if you need to manually build the rust dependencies with cargo build) I will push adding inject now.

You should be able to trigger a crash by adding Text("test") around line 192 in AltStore/Views/Settings/SettingsView.swift and saving.

Here's the stack trace (not sure if this is what you wanted):

[johnno1962]

Your problem is probably because you are not calling .eraseToAnyView() at the end of your SwiftUI property method. You need to do this if you are going to add or remove elements to the View over an injection as it changes the concrete type of the some View which the containing view won't be expecting and will crash. You need to do this ahead of time for any view you want to be able to inject. There is more information about this in the https://github.com/johnno1962/HotSwiftUI Swift Package or in the README https://github.com/johnno1962/InjectionIII#swiftui-injection

[amsam0]

Doesn't Inject already do this? https://github.com/krzysztofzablocki/Inject/blob/main/Sources/Inject/Integrations/SwiftUI.swift#L12

[johnno1962]

Inject contains an implementation of .eraseToAnyView() (where it is called enableinjection()) but it needs to be used as part of your SwiftUI view implementation. Have a look at https://github.com/johnno1962/SwiftUI-Kit/blob/master/Shared/ContentView.swift for example.

[amsam0]

https://github.com/SideStore/SideStore/blob/naturecodevoid/swiftui-improvements/AltStore/Views/RootView.swift#L32

I'm calling enableInjection, do I need to be doing something else?

[johnno1962]

Unfortunately you can't just do it at the top level. You need to add it to each component you want to be injectable to erase the type and isolate it from it's parent view.

[amsam0]

I see. If I want it on one view, do I need to add it to all child view/components?

[johnno1962]

Just the view(s) you want to iterate over.

[amsam0]

Ok, thanks! Do I also need to add the observer to every view, or just the root?

[amsam0]

I'll close this now, tysm for the help!

[johnno1962]

NP. You need and injectionObserver per view you want to auto-redraw.