Hi all! Has anyone ever used `LifecycleObserver`s for running `suspend` functions or collecting `Flo...

# android

[Tash]

Hi all! Has anyone ever used `LifecycleObserver`s for running suspend functions or collecting Flows via lifecycleOwner -> scope?

[Adam Powell]

you might find this https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:lifecycl[…]roidx/lifecycle/RepeatOnLifecycle.kt;l=63?q=repeatOnLifecycle and this https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:lifecycl[…]-runtime-ktx/src/main/java/androidx/lifecycle/FlowExt.kt;l=87 useful

[Adam Powell]

both available in the latest lifecycle-ktx alpha releases

[Tash]

Great! Thanks Adam. I’m assuming then that such a LifecycleObserver would only be interested in the onCreate() lifecycle method from which to launch coroutines? Otherwise, hooking into onStart() etc seems awkward/redundant

[Tash]

On the flipside, LifecycleObserver offers nice dependency inversion and direct access to the LifecycleOwner, but I can imagine it’d be nice to be able to inject/provide via DI some scoped Lifecycle for such “worker” classes that launch coroutines for specific/contained work. Not sure if that’s an anti-pattern, though 🤔

[Adam Powell]

The lifecycleScope extension on LifecycleOwner is exactly that, it spans onCreate => onDestroy: https://developer.android.com/reference/kotlin/androidx/lifecycle/package-summary#lifecyclescope

[Adam Powell]

repeatOnLifecycle runs one iteration of the given body block each time the lifecycle raises up to at least a given state, i.e. started: https://developer.android.com/reference/kotlin/androidx/lifecycle/package-summary#repeatonlifecycle

[Tash]

👍🏼 Even better. So then `LifecycleObserver`s are not really needed any more when doing work via coroutines. Just having a handle to the Lifecycle is enough given all these extension functions that are available.

[Adam Powell]

Not directly but all of these are using `LifecycleObserver`s under the hood, they're just nicer to use this way