androidx.navigation multiple destinations for menu item

Question

I have a single activity app using the androidx navigation library. For one of the menu destinations I effectively have a fragment as destination with no view whatsoever that depending on the state of the user provided configuration either redirects to the real destination that should be there or to one of currently two different views that tell the user that either he needs to setup a configuration first or that there currently is no active configuration (deleted?) and he needs to select one of the available configurations.

Now, functionally this approach works perfectly fine. However, since androidx navigation ties menu items to destinations by id the menu item that gets you to that view is never selected as it matches the fragment destination with no view in it.

I tried to add a NavController.OnDestinationChangedListener to my Activity and added it to the navController navController.addOnDestinationChangedListener(this). But it seems to get overwritten by the navigation afterwards.

override fun onDestinationChanged(controller: NavController, destination: NavDestination, arguments: Bundle?) {
    val destinations = listOf(R.id.destinationA, R.id.destinationB, R.id.destinationC)

    if(destinations.contains(destination.id)) {
        nav_view.menu.getItem(0).isChecked = true
    }
}

It is deffinitely the right menu item. As when I change isChecked = true to isEnabled = false I can no longer click on it.

Also when I do this odd hack it works

GlobalScope.launch(Dispatchers.Main) {
    delay(1000)
    nav_view.menu.getItem(0).isChecked = true
}

Needless to say this is not a very good solution.

---

Anyone here knows how to overwride the default behaviour of androidx navigation in this regard?

I´ll come back to this later and report back if I find a proper solution to this.

Adding a listener to the drawer opening and setting the selected menu item then might be a good workaround for this if it is not possible to do currently.

Answer 1

Instead of using setupWithNavController(), as mentioned in the documentation, setup it up yourself.

As mentioned here, onNavDestinationSelected() helper method in NavigationUI is called when the menu item is clicked when you set it up using setupWithNavController(). So you could try something like this:

yourNavigationView.setNavigationItemSelectedListener { item: MenuItem ->
    if(item.itemId == R.id.noViewFragmentId) {
        val isConfigurationProvided = ...
        if(!isConfigurationProvided) {
            //Perform your actions (navigate to either of the two alternate views)
            return@setNavigationItemSelectedListener true
        }
    }

    val success = NavigationUI.onNavDestinationSelected(item, navController)

    if(success) {
        drawerLayout.closeDrawer(GravityCompat.START)
        item.isChecked = true
    }
            
    success
}