How do you guys handle coroutine scopes in Fragmen...

# android

[nwh]

How do you guys handle coroutine scopes in Fragments? I find with most of my tasks that cancelling on pause is the most logical choice, as they are usually started when the view is created. But if I cancel the scope, I can't re-launch tasks on it upon resuming.

[matt tighe]

Do you have a viewmodel for the fragment? My viewmodels implement CoroutineScope, and that way they can continue doing their work through onPause. The fragments are updated through LiveData

[matt tighe]

Moving logic into a viewmodel has the side-effect of being unit-testable as well

[nwh]

I don't necessarily want my coroutine to continue to do their work while paused. If I do, then I use the ViewModel

[louiscad]

I create a scope in onStart that is automatically cancelled in onStop with the createScope function of self-made Splitties Lifecycle Coroutines library.

[nwh]

@louiscad what if, for example, you need to transition to another fragment after making a suspending call? Then you have to be in a scope that is canceled onPause, right? (to avoid duplicate transitions, ie multiple "go to other screen" button presses)

[louiscad]

@nwh I use suspending functions to handle clicks, so I can't have duplicate button presses problems. You can easily do the same by having a coroutine waiting for a click, then adding a delay(arbitraryDelay) after it in a while (isActive) loop. To await for a click, you can find to extensions for View in Splitties Views Coroutines: awaitOneClick() and visibleUntilClicked { … }.

[nwh]

Interesting, I'll take a look. Seems like for every problem I have, there is a Splitties library that fixes it

[louiscad]

For every problem I have, I think about if it could/should be a library 😉