Question regarding new androidx lifecycle (2.4.0) ...

# orbit-mvi

[Oleksii Malovanyi]

Question regarding new androidx lifecycle (2.4.0) and the article https://medium.com/androiddevelopers/a-safer-way-to-collect-flows-from-android-uis-23080b1f8bda

Isn’t the proper way to bound to the lifecycle is like?

@Composable
fun <STATE : Any, SIDE_EFFECT : Any> ContainerHost<STATE, SIDE_EFFECT>.collectAsState(
    minActiveState: Lifecycle.State = Lifecycle.State.STARTED
): State<STATE> {
    val lifecycleOwner = LocalLifecycleOwner.current
    val lifecycleAwareStateFlow = remember(this, lifecycleOwner) {
        container.stateFlow.flowWithLifecycle(lifecycleOwner.lifecycle, minActiveState)
    }
    return lifecycleAwareStateFlow.collectAsState(currentState)
}

[kioba]

Mikolaj or Matt can correct me if I am wrong.

My understanding is the flowWithLifecycle works only in case of cold Flow, where the repeat on lifecycle can cancel the `Flow`'s event generator.

--- Blogpost example --

Looking at the example in the post they accept a cold flow stream that provides Location data.

@Composable
fun LocationScreen(locationFlow: Flow<Flow>) 
...

Unsubscribing from locationFlow while compose is in the background might reduce the pressure on location services and we can resubscribe when the app comes to the foreground.

--- ContainerHost ---
ContainerHost contains a StateFlow which is hot and accepts state regardless the number of subscribers connected to the `StateFlow`'s instance. Adding a repeat won't cancel the generating source as it is providing states to the stateFlow.

[Oleksii Malovanyi]

@kioba basically you’re right as the main point of the new API is to cancel the underlying producer properly, but also, one more thing is about effects -> as the collect coroutine is now just suspended and not canceled, there is a chance to miss effects into the void during the resume (e.g. view destroy)

[kioba]

sorry, I haven't looked at the SideEffects before, It might be the case but I am not exactly sure how you mean missing an effect as the collector suspended.

[Oleksii Malovanyi]

e.g.: https://proandroiddev.com/android-singleliveevent-redux-with-kotlin-flow-b755c70bb055 see A Safe Observer of Events