IllegalArgumentException: navigation destination xxx is unknown to this NavController

Question

I am having issue with the new Android Navigation Architecture component when I try to navigate from one Fragment to another, I get this weird error:

Answer 1

I got this same error because I used a Navigation Drawer and getSupportFragmentManager().beginTransaction().replace( ) at the same time somewhere in my code .

I got rid of the error by using this condition(testing if the destination) :

if (Navigation.findNavController(v).getCurrentDestination().getId() == R.id.your_destination_fragment_id)
Navigation.findNavController(v).navigate(R.id.your_action);

In my case the previous error was triggered when I was clicking on the navigation drawer options. Basically the code above did hide the error , because in my code somewhere I used navigation using getSupportFragmentManager().beginTransaction().replace( ) The condition -

 if (Navigation.findNavController(v).getCurrentDestination().getId() ==
  R.id.your_destination_fragment_id) 

was never reached because (Navigation.findNavController(v).getCurrentDestination().getId() was always poiting to home fragment. You must only use Navigation.findNavController(v).navigate(R.id.your_action) or nav graph controller functions for all your navigation actions.

Answer 2

I caught this exception after some renames of classes. For example: I had classes called FragmentA with @+is/fragment_a in navigation graph and FragmentB with @+id/fragment_b. Then I deleted FragmentA and renamed FragmentB to FragmentA. So after that node of FragmentA still stayed in navigation graph, and android:name of FragmentB's node was renamed path.to.FragmentA. I had two nodes with the same android:name and different android:id, and the action I needed were defined on node of removed class.

Answer 3

A Ridiculous way but very powerful is: Simply call this:

view?.findNavController()?.navigateSafe(action)

Just Create this Extention:

fun NavController.navigateSafe(
    navDirections: NavDirections? = null
) {
    try {
        navDirections?.let {
            this.navigate(navDirections)
        }
    }
    catch (e:Exception)
    {
        e.printStackTrace()
    }
}

Answer 4

In my case I was using a custom back button for navigating up. I called onBackPressed() in stead of the following code

findNavController(R.id.navigation_host_fragment).navigateUp()

This caused the IllegalArgumentException to occur. After I changed it to use the navigateUp() method in stead, I didn't have a crash again.

Answer 5

You can check before navigating if the Fragment requesting the navigation is still the current destination, taken from this gist.

It basically sets a tag on the fragment for later lookup.

/**
 * Returns true if the navigation controller is still pointing at 'this' fragment, or false if it already navigated away.
 */
fun Fragment.mayNavigate(): Boolean {

    val navController = findNavController()
    val destinationIdInNavController = navController.currentDestination?.id
    val destinationIdOfThisFragment = view?.getTag(R.id.tag_navigation_destination_id) ?: destinationIdInNavController

    // check that the navigation graph is still in 'this' fragment, if not then the app already navigated:
    if (destinationIdInNavController == destinationIdOfThisFragment) {
        view?.setTag(R.id.tag_navigation_destination_id, destinationIdOfThisFragment)
        return true
    } else {
        Log.d("FragmentExtensions", "May not navigate: current destination is not the current fragment.")
        return false
    }
}

R.id.tag_navigation_destination_id is just an id you'll have to add to your ids.xml, to make sure it's unique. <item name="tag_navigation_destination_id" type="id" />

More info on the bug and the solution, and navigateSafe(...) extention methods in "Fixing the dreaded “… is unknown to this NavController”

Answer 6

After thinking over Ian Lake's advice in this twitter thread I've came up with following approach. Having NavControllerWrapper defined as such:

class NavControllerWrapper constructor(
  private val navController: NavController
) {

  fun navigate(
    @IdRes from: Int,
    @IdRes to: Int
  ) = navigate(
    from = from,
    to = to,
    bundle = null
  )

  fun navigate(
    @IdRes from: Int,
    @IdRes to: Int,
    bundle: Bundle?
  ) = navigate(
    from = from,
    to = to,
    bundle = bundle,
    navOptions = null,
    navigatorExtras = null
  )

  fun navigate(
    @IdRes from: Int,
    @IdRes to: Int,
    bundle: Bundle?,
    navOptions: NavOptions?,
    navigatorExtras: Navigator.Extras?
  ) {
    if (navController.currentDestination?.id == from) {
      navController.navigate(
        to,
        bundle,
        navOptions,
        navigatorExtras
      )
    }
  }

  fun navigate(
    @IdRes from: Int,
    directions: NavDirections
  ) {
    if (navController.currentDestination?.id == from) {
      navController.navigate(directions)
    }
  }

  fun navigateUp() = navController.navigateUp()

  fun popBackStack() = navController.popBackStack()
}

Then in navigation code:

val navController = navControllerProvider.getNavController()
navController.navigate(from = R.id.main, to = R.id.action_to_detail)