I have an unexpected (to me at least) behaviour with `OnDestinationChangedListener` of the Navigatio...

# compose

[Jordi Saumell]

I have an unexpected (to me at least) behaviour with OnDestinationChangedListener of the Navigation component. I have a bottom nav bar with 3 items, and the third is a subgraph. When I navigate to that one my OnDestinationChangedListener gets called twice, first with the start destination and then with the actual destination.
Is this the intended behaviour?

[Jordi Saumell]

Also, what I am trying to achieve, in case someone has a better solution:
When I click on one of the bottom items I save the route of destination in an observable so that I can use it to know which item should be highlighted.
This does not work when using the system back, so I added a OnDestinationChangedListener to detect when the start destination was opened and update the observable with the start destination. As the OnDestinationChangedListener goes through the start destination, it breaks my solution.

[Ian Lake]

You shouldn't be directly using an OnDestinationChangedListener at all within Compose, use the currentBackStackEntryAsState() as the documentation does: https://developer.android.com/jetpack/compose/navigation#bottom-nav

[Ian Lake]

If you're using the popUpTo style shown there, you won't get any intermediate state such as the start destination being dispatched like you would if you did it with a separate popBackStack() followed by a navigate()

[Jordi Saumell]

Thank you, it seems to work! How are you so fast??

Also, is this new or sort of new? I diverged from the implementation of the documentation because I would get 2 start destinations on the backstack, and another issue I do not remember right now

[Ian Lake]

The popUpTo stuff came in alpha02 back in November, fixes for nested graphs came in alpha03 in December, so not that recent, no