Using compose navigation and a single activity app...

# compose

[Colton Idle]

Using compose navigation and a single activity app, I have a composable SignInScreen that should not follow the typical "back press = popBackStack". When on the SignInScreen, the MainScreen is in the stack, but in this case I want the app to just close.

Where is the more appropriate place to override this? In the SignInScreen composable itself? Or on the activity level?

[Colton Idle]

Basically this is what I had, and want to make sure I'm using the right api

@Composable
fun SignInScreen(
    backPressed: () -> Unit,
    viewModel: SignInScreenViewModel = hiltViewModel()
) {

LocalOnBackPressedDispatcherOwner.current!!.onBackPressedDispatcher.addCallback {
        backPressed()
    }
... //my content
}

then in my activity I have

SignInScreen(
    { [e-mail]() },
)

[Colton Idle]

A negative to this approach I've noticed is that if I have another screen I was taken to from my SignInScreen (for example, lets say ForgotPasswordScreen), then actually pressing back on ForgotPasswordScreen will actually finish the activity too.

So it sounds like I'm doing something wrong. Any advice is appreciated.

[yousefa2]

SignInScreen is the best place but you should use DisposableEffect to register the back pressed callback when SignInScreen is displayed then re-registering de-registering the callback when it’s disposed

[Colton Idle]

Nice. Thanks for linking to the docs. I'll try this out now!

[Colton Idle]

@yousefa2 holy crap. It works! Thank you!

[yousefa2]

Nice! Happy to help .. just spotted a typo but I am sure you figured it out nevertheless 🙂

[Colton Idle]

Oh. A typo where?

[yousefa2]

Just edited my original answer with a strikethrough

[Colton Idle]

Ah. I got what you mean. Thanks. I thought you were saying that the docs had a typo. lol

[Colton Idle]

@yousefa2 found out that you can just use this new composable added in activity-compose artifact
https://developer.android.com/reference/kotlin/androidx/activity/compose/package-summary

BackHandler { onBack() }

AWESOME

[yousefa2]

That makes it easy then 😄 .. nice one!