Got a situation where I got this setup: `RootActiv...

# compose

[Stylianos Gakis]

Got a situation where I got this setup:
RootActivity (which opens ChildActivity) -> ChildActivity (which contains a NavHost that I will mention here).
And I got some trouble with navigateUp(). More in 🧵

[Stylianos Gakis]

Inside this navHost, I got this structure:

NavHost(startDestination = "A") {
  navigation(
    route = "A",
    startDestination = "First",
  ) {
    composable(route = "First") {
      FirstComposable(
        navigateToSecond = { navController.navigate("Second") { popUpTo("A") } },
        onBack = { navController.navigateUp() || [e-mail]() || [e-mail]() }
      )
    }
    composable(route = "Second") {
      SecondComposable(onBack = { navController.navigateUp() || [e-mail]() || [e-mail]() })
    }
  }
}

Where I want to go to First, from there move to Second, but remove “First” off the backstack, so that from “Second”, if we’ve not been deep linked into there, when they press on the topAppBar back arrow icon, navController.navigateUp() doesn’t succeed, onSupportNavigateUp() also doesn’t succeed and it falls back to finish().
When I call onBack() from inside FirstComposable, this works fine, and the activity is finished. When I then trigger the navController.navigate("Second") { popUpTo("A") }, and from inside SecondComposable I call onBack, it somehow tried to re-instantiate my ChildActivity instead since navController.navigateUp() does succeed somehow, even though I thought I’d have an empty backstack at that point since I popped it all before going to “Second”.
I wonder if there’s something wrong I am doing with my popUpTo and how I should be doing this properly in case I am in such a nested graph situation. Or if it’s something else I am messing up

[Stylianos Gakis]

In this case I guess one thing I may be messing up is what I should decide to do with my popUpTo.
In order to get this “clear backstack, aside from “Second” being in the front” if I should do
• navController.navigate(“Second”) { popUpTo(“A”) }
• navController.navigate(“Second”) { popUpTo(“First”) }
• navController.navigate(“Second”) { popUpTo(“A”) { inclusive = true } }
• navController.navigate(“Second”) { popUpTo(“First”) { inclusive = true } }
• something else
Not sure tbh, and I haven’t found anything in the docs specifying this, only cases where there aren’t nested graphs like this, like here.

[Stylianos Gakis]

I guess what I was facing actually had to do with what navController.navigateUp() does and how it works differently when called from the startDestination of a navigation graph, vs when called from another route which is not he start destination.
At least that’s what I think I figured out here 🤷‍♂️