How to handle one-shot operations in Jetpack Compose?

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I prefer using SharedFlow for a job like this:

class OneShotOperationViewModel : ViewModel() {
    private val _toastMessage = MutableSharedFlow<String>()
    val toastMessage = _toastMessage.asSharedFlow()

    fun sendMessage(message: String) {
        viewModelScope.launch {
            _toastMessage.emit(message)
        }
    }
}

@Composable
fun TestScreen() {
    val context = LocalContext.current

    val viewModel = viewModel<OneShotOperationViewModel>()
    LaunchedEffect(Unit) {
        viewModel
            .toastMessage
            .collect { message ->
                Toast.makeText(
                    context,
                    message,
                    Toast.LENGTH_SHORT,
                ).show()
            }
    }
    Button(
        onClick = {
            viewModel.sendMessage("Sample Toast")
        },
    ) {
        Text(text = "Show Toast")
    }
}

Note that if you send a message from another view while collect is not running, it will not show toast when you finally start it. It does not store the value, it only passes it on to all the collectors that are currently connected.

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