Ok I might be too tired to work on this at 11pm instead of g kotlinlang #compose

Ok I might be too tired to work on this at 11pm instead of going to sleep, but what is wrong with this that the load of the value doesn’t trigger recomposition?

Copy code

@Composable
fun ProfileScreen(userUid: String) {

    val userRepository = UserRepository()
    val user = mutableStateOf<User?>(null)

    launchInComposition {
        user.value = userRepository.get(userUid)
        Log.d(TAG, "url = ${user.value?.profileUrl}")
    }

    user.value?.profileUrl?.let { CoilImage(data = it) } ?: Text("No Image!")
}

Zach Klippenstein (he/him) [MOD]

07/29/2020, 8:30 PM

val userRepository = UserRepository()

UserRepository

a regular constructor or function? If so, this should be

remember { UserRepository() }

val user = mutableStateOf<User?>(null)

Similar here, this should be

remember { mutableStateOf<User?>(null) }

launchInComposition {

If you want this coroutine to re-launch when the user ID changes, do

launchInComposition(userUid) {

🔥 1

👍 1

➕ 1

There’s also a

state<User?> { null }

function, but that’s being deprecated and replaced by

remember { mutableStateOf() }

Without the

remember

calls, both your repository and that

MutableState

object will be instantiated on every composition pass.

👍 2

The documentation on

launchInComposition

explains what the

key

parameter is for: https://developer.android.com/reference/kotlin/androidx/compose/package-summary#launchincomposition_1

galex

07/30/2020, 9:25 AM

Thank you for your explanations, it starts to become clearer! Here

UserRepository

is a new Object which will be passed to this Composable. And yes I misued

launchInComposition

, I thought that as it sounds like

launch

it’s the same signature but no 🙂