Using compose navigation, how can I make sure one destination has only one instance? I'm handling a ...

# compose

[Tgo1014]

Using compose navigation, how can I make sure one destination has only one instance? I'm handling a intent from the main screen to a detail screen, but if the user click many times the intent then when pressing back it goes to the previous detail screen instead of the main screen

[Francesc]

you can query the current destination before you try to navigate, if you are no longer where you expect to be then ignore the button click

[Tgo1014]

I found this, settings where it should pop up to works I guess: https://stackoverflow.com/a/71412193/6022725

[Francesc]

when you handle the button click, you can check this

if (navController.currentBackStackEntry?.destination != <nav id of where the button is>) {
   // navigate
}

[Tgo1014]

Let me try

[Francesc]

you probably want to get the route or the id from the backstack entry to compare, I'm just typing this from memory

[Tgo1014]

Hmm but in my case it doesn't work because I still need to navigate, the thing is when going back

[Tgo1014]

My issue is like A -> B -> B -> B

[Tgo1014]

so when I go back instead of always A -> B

[Francesc]

do you want to debounce clicks on the back button to navigate back?

[Tgo1014]

No, I want to go back to the first one, skipping all the B instances

[Francesc]

then you can use popUpTo(A, inclusive = false)

[Tgo1014]

Using this solved for now, just not sure it's the best way

navController.navigate(B) {
    popUpTo(A) {
         inclusive = false
    }
}

[Francesc]

not popUpTo but popBackStack but that's the idea

[Tgo1014]

I tried popBackStack but for wear when you swipe back it goes back to another B, if I set it as popUpTo then it works 👀

[Ian Lake]

This is exactly what launchSingleTop is for. Have you tried using that?

[Ian Lake]

to only have a single instance of a destination on the top of the stack

[Tgo1014]

Isn't this a Manifest thing? I've just one activity where all destinations are composable screens

[Ian Lake]

navController.navigate(B) {
  launchSingleTop = true
}

[Tgo1014]

Oh, I didn't know you could use it like this, seems like this would solve the problem 😄

[Ian Lake]

Covered in the docs, FWIW: https://developer.android.com/jetpack/compose/navigation#nav-to-composable

[Tgo1014]

Yeah, my google search failed me 😄 Thanks for the help Ian!