Is it true that when using compose navigation for ...

# compose-android

[Mark]

Is it true that when using compose navigation for an Activity with launchMode="singleTop", the app needs to implement onNewIntent() (probably using navController.handleDeepLink(intent) )?

[Ian Lake]

https://kotlinlang.slack.com/archives/C04TPPEQKEJ/p1737767279633079?thread_ts=1737386063.841679&cid=C04TPPEQKEJ

[Mark]

Thanks Ian, but I want to keep as much compose code platform-neutral as possible. Can’t I just pass in (to the screen composable) a Flow of (NavController) -> Unit and let the Activity implement that flow?

private val handleDeepLinkEventBus = SingleShotEventBus<(NavController) -> Unit>()
private val handleDeepLinkFlow: Flow<(NavController) -> Unit>
    get() = handleDeepLinkEventBus.events

override fun onNewIntent(intent: Intent) {
    super.onNewIntent(intent)
    setIntent(intent) // Update the intent to the new one
    handleDeepLinkEventBus.trySend { navController ->
        navController.handleDeepLink(intent)
    }
}

[Ian Lake]

I'd think an OnNewIntentEffect(NavController) that is just a no-op on non-Android would be way easier to reason about, but you do you

[Mark]

I guess you’re saying that this is only applicable to Android anyway, in which case I agree. My thinking was that if this logic would be applicable to any other platform, then my approach would make sense.

[Ian Lake]

If it applied on another platform, that effect could be...not a no-op there too. Really just depends whether you want the logic to live in composition, near your NavController, or if you want to put code in a global place like at your activity level

[Mark]

Makes sense. Regardless, my above solution is unnecessary. As a middle ground I’m happy to keep the code in both compose and the Activity, by passing in the navController. It’s trivial to move that code in or out of the AppScreen composable, so a moot point IMO.

setContent {
    val mainNavController = rememberNavController()
    DisposableEffect(Unit) {
        val listener = Consumer<Intent> { intent ->
            mainNavController.handleDeepLink(intent)
        }
        addOnNewIntentListener(listener)
        onDispose { removeOnNewIntentListener(listener) }
    }
    AppScreen(mainNavController)
}

Thanks for your quick feedback Ian. 🙏

[Ian Lake]

Looks good to me 👍

[Mark]

Oh maybe I should add mainNavController as a key to the DisposableEffect?

[Ian Lake]

I don't think it matters in this particular case, but yes that's generally a good habit to get into