How to call a composable function after a certain time in Jetpack Compose?

delay is a suspend function and cannot be called from a composable. You have to wrap it in a LaunchedEffect first.

Furthermore, Compose is state-based, so whatever you do after the delay it must result in a changed state.

It could look something like this:

var waitUntil by rememberSaveable { mutableStateOf(Clock.System.now() + 30.seconds) }
var isWaiting by rememberSaveable { mutableStateOf(true) }

LaunchedEffect(waitUntil) {
    delay(waitUntil - Clock.System.now())
    isWaiting = false
}

if (isWaiting) {
    CircularProgressIndicator()
} else {
    Text("The wait is over.")
}

waitUntil is the time until it should be waited. Whenever that changes the LaunchedEffect is executed, delaying until that time is reached. Afterwards isWaiting is set to false, which will then trigger a recomposition, switching your UI from the progress indicator to a text.

The LaunchedEffect is cancelled and restarted in the following cases:

1. Whenever waitUntil changes (because it is passed as a key parameter to the LaunchedEffect).
2. After a configuration change (like a device rotation) results in a recreation of the activity and the entire Compose tree to be rebuilt.
3. After system-initiated process death, i.e. when the user sends your app to the background and the Android system decides to kill the process to save resources. When the user brings the app back to the foreground, the LaunchedEffect continues to wait (if there is time left, of course).

Especially for the cases 2. and 3. it is important that waitUntil and isWaiting are stored using rememberSaveable, otherwise their state will be lost.

@Composable
fun AppRoot() {
    var showNav by rememberSaveable { mutableStateOf(false) }

    // Runs once while this composable is in the composition
    LaunchedEffect(Unit) {
        delay(30_000)            // 30 seconds without blocking the main thread
        showNav = true           // drive UI via state
    }

    if (showNav) {
        NavBar()                 // your target UI
    } else {
        SplashAnimation()        // your initial animation UI
    }
}

This is the easiest way to achieve it