So I'm trynna replace my LiveData with a StateFlow. I want to trigger an update whenever it's first ...

# coroutines

[Se7eN]

So I'm trynna replace my LiveData with a StateFlow. I want to trigger an update whenever it's first accessed. I was using liveData builder before like this:

val users = liveData {
    emit(getUsers(count=20))
}

With StateFlow, I'm doing it with `lazy`:

val users by lazy {
    MutableStateFlow<List<User>>(listOf()).also { usersFlow ->
        viewModelScope.launch {
            usersFlow.value = getUsers(count = 20)
        }
    }
}

Just wanna know if it's fine to do it this way?

[Erik]

Not sure if entirely equivalent, but could you simply MutableStateFlow(...).onStart { emit(getUsers(count = 20)) }?

[Se7eN]

I tried but it doesn't work for me. I think it would work if I added a collect after the onStart but that's not how I'm doing it. Also onStart converts it to Flow so I can't add that while initializing

[Erik]

Your UI should be collecting the flow. When that starts, the underlying mutable state flow emits the value before anything else

[Se7eN]

I'm using jetpack compose. I'm collecting the flow using StateFlow.collectAsState but the onStart never runs. Is this a bug?

[Erik]

Well, there's the initial value of a mutable state flow, but I'm sure you had noticed that before

[Se7eN]

Yep the initial value is collected which is an empty list but onStart never gets called

[Erik]

onStart is only called when a collector starts collecting

[Se7eN]

Yes I'm collecting using collectAsState from jetpack compose

[Erik]

For simplicity I guess that your suggested code should be fine, unless you don't want to emit and empty list initially.

[Se7eN]

Alright. I'd probably wrap it in a network state later