`rememberSaveable` does not work - restore/save logic is never called

I currently have:

    val appState = remember { AppState() }

I thought I would try switching to rememberSaveable so that app settings would persist across app invocations.

So I changed it to:

    val appState = rememberSaveable(saver = AppState.Saver) { AppState() }

AppState.Saver is currently just:

    val Saver = object : Saver<AppState, Any> {
        override fun restore(value: Any): AppState? {
            TODO("Not yet implemented")
        }

        override fun SaverScope.save(value: AppState): Any? {
            TODO("Not yet implemented")
        }
    }

If I put a breakpoint on those TODO lines, I can see that they are never called. I’d expect a call to save during application exit, and a call to restore some time during startup.

I assume there’s a way to call the right things programmatically to get this to happen as a workaround but haven’t figured it out yet.

[hakanai]

I partially agree, except:

1. It isn’t clear that Compose is just a “UI framework”. The docs really make it seem like an “app framework” instead - code examples show the main function directly calling their singleWindowApplication function, i.e. the very first line of code is Compose code.

2. This means I have to reinvent the wheel even though surely I am not the only person trying to use this framework to make full applications.

So yeah, Compose may be a UI framework and not an app framework, but if that’s the case, things like rememberSaveable are confusing at best, and it means we have to wait for someone to make an actual app framework which is built on Compose until we can really develop apps with ease, because “just putting state in some object and serialising it” is not trivial.

[hakanai]

No… I didn’t have the slightest idea where to start.