Hi guys, I’m trying to validate a TextField with Jetpack Compose using StateFlow on a ViewModel I sa...

# compose

[Jose Carlos Hernandez]

Hi guys, I’m trying to validate a TextField with Jetpack Compose using StateFlow on a ViewModel I saw an example that looks like this:

val isButtonEnabled: StateFlow<Boolean> =
        combine(isLoading, login, password) { isLoading, login, password ->
            isLoading.not() && login.isNotBlank() && password.isNotBlank()
        }.stateIn(viewModelScope, SharingStarted.Eagerly, false)

But I only have 1 field instead to validate so I try to put it like this

val isContinueEnable: StateFlow<Boolean> = MutableStateFlow(login.value.isNotBlank())
        .stateIn(viewModelScope, SharingStarted.Eagerly, false)

but when I start typing on the TextField it doesn’t change de value to true so is there a method similar to combine to get Flow but just with one element?

[Landry Norris]

I would use login.map { it.isNotBlank() } instead of a MutableStateFlow. You are currently getting the initial value of login.isNotBlank and using that to initialize a MutableStateFlow, but you never mutate the flow you create.

[Landry Norris]

You can think of combine as a way to map multiple flows at once.

[Jose Carlos Hernandez]

nice! that was exactly what I wanted but didn’t knew the map function… thank you man!