Hi. I have to clear db when exit fragment. I am cr...

# coroutines

[Khan]

Hi. I have to clear db when exit fragment. I am creating a coroutine to clear db table inside viewmodel onCleared. As you can see i am not using viewModelScope because my table will not be cleared and coroutine will be cancelled. Do you think its fine to use CoroutineScope here?

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[Martin Nordholts]

Add a scope to your repository by inheriting from : CoroutineScope by MainScope(), then you can launch from within your repository instead of from outside it

[Paul Woitaschek]

I douldn't do that. You are exposing a buch of stuff then. For example you can close your repository now from the outside 😉

[Paul Woitaschek]

A repository is no CoroutineScope, a repository can have a CoroutineScope.

[Martin Nordholts]

If that is of concern, then better to add a private val coroutineScope = CoroutineScope(SupervisorJob() + Dispatchers.Main) and use coroutineScope.launch

[Martin Nordholts]

Personally I have no problem with a repository being a scope though. Especially not in Kotlin where it is by delegation and does not put a limit on your inheritance hierachy.

[Khan]

I have a confusion. Will this coroutineScope leak if app closes?

[Martin Nordholts]

if it doesn’t leak while the app is running, it will not leak when the app is closed.

[Khan]

So for example if i create a coroutine in repo and then i exit from screen & my coroutine is still running. Anything bad in that?

[Martin Nordholts]

Nope. Assuming that your coroutine will come to a stop eventually..

[Khan]

It creates a new scope inside ViewModel and does not cancel itself, if it’s not finishing the job before the ViewModel gets cleared then the ViewModel can’t be garbage collected and a leak will occur.

Is this a correct statement in the above context?

[Martin Nordholts]

It creates a new scope inside ViewModel

No one has talked about creating a scope in a ViewModel.