I ve been migrating our code to compose navigation We re usi

Question

I ve been migrating our code to compose navigation We re using MVVM but the navigation does not go through the ViewModel and we delegate it directly to the composable up to the navigation graph For user interaction that does some processing before navigation such as login we expose a `suspend fun` which returns the operation s result and navigate accordingly Works fine so far and now I encountered a new use case integrating with non Kotlin code I use CameraX ImageCapture use case with takes a listener for successful capture I can t use suspend fun to wait for the result So now I m looking for options I wonder if we could represent capture events from the ViewModel and I remember discussions on SingleLiveEvents and we now prefer representing state instead of events in Compose For example we now use state for snackbar or dialog visibility instead of SingleLiveEvent I m not sure how to do this for navigation events I ve seen articles suggesting `StateFlow` `SharedFlow` `Channel` for navigation events but I m curious what the Compose team thinks I haven t found an official example where the navigation is handled within the ViewModel is it deliberate that we want to decouple ViewModels from the Views navigations completely no mention of navigation within a ViewModel We re also having internal discussions how to handle navigation in our Compose+MVVM architecture and we re split on what we need to do about whether we should call the navigation lambda directly on user event like onClick or whether we should keep our Composables pure amp passive

allan.conda · Answer

Basically in general we re split on whether we should do something like this ```Screen state = viewModel state toLogin = actions toLogin ``` Or this ```viewModel navigateToLoginEvent observe actions toLogin Screen onLoginButtonClick = viewModel onLoginButtonClick ``` We are doing the former currently but we re not sure we re following MVVM correctly by doing this Technically our Composables know when to navigate instead of simply delegating the user event somewhere else such as into the ViewModel

Albert Chang · Answer

Jetnews <https github com android compose samples blob 9f9d82ac863815a8a798c6c5271de6990eed012d JetNews app src main java com example jetnews ui Navigation kt L107|used to> use ViewModel for navigation

Albert Chang · Answer

By the way you can use `suspendCancellableCoroutine` to convert a callback into a suspend function