Is this shady/wrong? Background: `onTaskSelected` calls `first()` on the `selectedTask` flow. But ap...

# coroutines

[Florian]

Is this shady/wrong? Background: onTaskSelected calls first() on the selectedTask flow. But apparently, I can't do that in the init block of this ViewModel because then the Flow is not initialized yet. So the temporary collect makes sure that the selectedTask Flow is ready.

ViewModel {

init {
    if (taskIdToSelect != null && taskIdToSelect != Task.NO_ID) {
        CoroutineScope(Dispatchers.Main).launch {
            selectedTask.collect {
                onTaskSelected(taskIdToSelect.toLong())
                cancel()
            }
        }
    }
}

[bezrukov]

🤔 if you can collect it, why can't you call first()? I mean how collect helps you in case if flow is not initialized? Most likely launch helps you, not a collect call

[Florian]

ah good point

[Florian]

let me try

[Florian]

Nah it actually doesn't work without the collect

[Florian]

I don't know why collect works in init but first doesn't

[bezrukov]

that's strange because basically first() does collect inside. Maybe with collect it works because onTaskSelected is called for 2nd, 3rd,.., Nth emission?
What do you mean by "doesn't work"? is it crashes or does nothing? Anyway without understanding what's going on yes, it looks wrong/hacky

[Florian]

apparently, you can't call first() on a Flow inside an init block of that same object

[bezrukov]

Even from the launch fun? Maybe flow is declared below init block? In this case just move it to top

[bezrukov]

Could you provide minimal selft-contained example?

[Florian]

Maybe flow is declared below init block? In this case just move it to top

holy shit that actually solved it

[Florian]

I'm such a noob

[Florian]

thank you

[Joffrey]

Please don't use the CoroutineScope factory function this way, you need to store that scope somewhere and cancel it appropriately when your component's lifecycle ends. In this case, it seems you are in a view model so you should have access to viewModelScope

[Florian]

gotcha