Hi ! I have a `@Composable` : `GamePage` , which i...

# compose

[loloof64]

Hi ! I have a @Composable : GamePage , which is using a native library. But this native library must be stopped when not needed any more:

@Composable
fun GamePage() {
val myLib = MyLib()

...
myLib.stop()
}

So, is there a way to ?
1. Build a new MyLib instance at each recomposition
2. But also stop it before the next recomposition
3. Can I wait some milliseconds before "commiting" the next recomposition ?

[Kirill Grouchnikov]

Sounds like you're looking for DisposableEffect

[loloof64]

Thank you. I've looked at DisposableEffect documentation, but I did not thought that it was adapted for my use case 🙂

[Kirill Grouchnikov]

It's a bit vague right now, but it sounds like you'd remember your MyLib with one of the existing wrappers, and then call stop() on it in DisposableEffect of this composable

[loloof64]

By wrappers, do you mean remember or rememberSaveable ?

[Lebron James]

@Composable
fun HomeScreen(
    lifecycleOwner: LifecycleOwner = LocalLifecycleOwner.current,
    onStart: () -> Unit, // Send the 'started' analytics event
    onStop: () -> Unit // Send the 'stopped' analytics event
) {
    // Safely update the current lambdas when a new one is provided
    val currentOnStart by rememberUpdatedState(onStart)
    val currentOnStop by rememberUpdatedState(onStop)

    // If `lifecycleOwner` changes, dispose and reset the effect
    DisposableEffect(lifecycleOwner) {
        // Create an observer that triggers our remembered callbacks
        // for sending analytics events
        val observer = LifecycleEventObserver { _, event ->
            if (event == Lifecycle.Event.ON_START) {
                currentOnStart()
            } else if (event == Lifecycle.Event.ON_STOP) {
                currentOnStop()
            }
        }

        // Add the observer to the lifecycle
        lifecycleOwner.lifecycle.addObserver(observer)

        // When the effect leaves the Composition, remove the observer
        onDispose {
            lifecycleOwner.lifecycle.removeObserver(observer)
        }
    }

    /* Home screen content */
}

This is an official example

[loloof64]

Yes, thank you.
I've seen it from https://developer.android.com/jetpack/compose/side-effects#disposableeffect.

And this is the way I'm using it

DisposableEffectUsage.kt

[Lebron James]

you're welcome. It looks great. I've learned a lot.