How to set Double back press Exit in Jetpack Compose?

Question

There are some tutorials on YouTube about how to set double back press exit in XML android, but most of them are in JAVA and None of them are in Jetpack Compose.

So how can we set that Double back press in Jetpack Compose?

I mean that thing that ask us in a Toast to press back again if we are sure to Exit. Thanks for help

Answer 1

This sample shows Toast on first touch and waits for 2 seconds to touch again to exit app otherwise goes back to Idle state.

sealed class BackPress {
    object Idle : BackPress()
    object InitialTouch : BackPress()
}

@Composable
private fun BackPressSample() {
    var showToast by remember { mutableStateOf(false) }

    var backPressState by remember { mutableStateOf<BackPress>(BackPress.Idle) }
    val context = LocalContext.current

    if(showToast){
        Toast.makeText(context, "Press again to exit", Toast.LENGTH_SHORT).show()
        showToast= false
    }


    LaunchedEffect(key1 = backPressState) {
        if (backPressState == BackPress.InitialTouch) {
            delay(2000)
            backPressState = BackPress.Idle
        }
    }

    BackHandler(backPressState == BackPress.Idle) {
        backPressState = BackPress.InitialTouch
        showToast = true
    }
}