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:
java.lang.IllegalArgumentException: navigation destination XXX
is unknown to this NavController
Every other navigation works fine except this particular one.
I use:
findNavContoller()
extension function of Fragment to get access to the navControler.
Any help will be appreciated.
In my case, if the user clicks the same view twice very very quickly, this crash will occur. So you need to implement some sort of logic to prevent multiple quick clicks... Which is very annoying, but it appears to be necessary.
You can read up more on preventing this here: Android Preventing Double Click On A Button
Edit 3/19/2019: Just to clarify a bit further, this crash is not exclusively reproducible by just "clicking the same view twice very very quickly". Alternatively, you can just use two fingers and click two (or more) views at the same time, where each view has their own navigation that they would perform. This is especially easy to do when you have a list of items. The above info on multiple click prevention will handle this case.
Check currentDestination before calling navigate might be helpful.
For example, if you have two fragment destinations on the navigation graph fragmentA and fragmentB, and there is only one action from fragmentA to fragmentB. calling navigate(R.id.action_fragmentA_to_fragmentB) will result in IllegalArgumentException when you were already on fragmentB. Therefor you should always check the currentDestination before navigating.
if (navController.currentDestination?.id == R.id.fragmentA) {
navController.navigate(R.id.action_fragmentA_to_fragmentB)
}
You can check requested action in current destination of navigation controller.
UPDATE added usage of global actions for safe navigation.
fun NavController.navigateSafe(
@IdRes resId: Int,
args: Bundle? = null,
navOptions: NavOptions? = null,
navExtras: Navigator.Extras? = null
) {
val action = currentDestination?.getAction(resId) ?: graph.getAction(resId)
if (action != null && currentDestination?.id != action.destinationId) {
navigate(resId, args, navOptions, navExtras)
}
}
It could also happen if you have a Fragment A with a ViewPager of Fragments B And you try to navigate from B to C
Since in the ViewPager the fragments are not a destination of A, your graph wouldn't know you are on B.
A solution can be to use ADirections in B to navigate to C
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.
What I did to prevent the crash is the following:
I have a BaseFragment, in there I've added this fun to ensure that the destination is known by the currentDestination:
fun navigate(destination: NavDirections) = with(findNavController()) {
currentDestination?.getAction(destination.actionId)
?.let { navigate(destination) }
}
Worth noting that I'm using the SafeArgs plugin.
In my case, the issue occurred when I had re-used one of my Fragments inside a viewpager fragment as a child of the viewpager.
The viewpager Fragment(which was the parent fragment) was added in the Navigation xml, but the action was not added in the viewpager parent fragment.
nav.xml
//reused fragment
<fragment
android:id="@+id/navigation_to"
android:name="com.package.to_Fragment"
android:label="To Frag"
tools:layout="@layout/fragment_to" >
//issue got fixed when i added this action to the viewpager parent also
<action android:id="@+id/action_to_to_viewall"
app:destination="@+id/toViewAll"/>
</fragment>
....
// viewpager parent fragment
<fragment
android:id="@+id/toViewAll"
android:name="com.package.ViewAllFragment"
android:label="to_viewall_fragment"
tools:layout="@layout/fragment_view_all">
Fixed the issue by adding the action to the parent viewpager fragment also as shown below:
nav.xml
//reused fragment
<fragment
android:id="@+id/navigation_to"
android:name="com.package.to_Fragment"
android:label="To Frag"
tools:layout="@layout/fragment_to" >
//issue got fixed when i added this action to the viewpager parent also
<action android:id="@+id/action_to_to_viewall"
app:destination="@+id/toViewAll"/>
</fragment>
....
// viewpager parent fragment
<fragment
android:id="@+id/toViewAll"
android:name="com.package.ViewAllFragment"
android:label="to_viewall_fragment"
tools:layout="@layout/fragment_view_all"/>
<action android:id="@+id/action_to_to_viewall"
app:destination="@+id/toViewAll"/>
</fragment>
In my case the bug ocurred because I had a navigation action with the Single Top and the Clear Task options enabled after a splash screen.
It seems like you are clearing task. An app might have a one-time setup or series of login screens. These conditional screens should not be considered the starting destination of your app.
https://developer.android.com/topic/libraries/architecture/navigation/navigation-conditional
TL;DR Wrap your navigate calls with try-catch (simple way), or make sure there will be only one call of navigate in short period of time. This issue likely won't go away. Copy bigger code snippet in your app and try out.
Hello. Based on a couple of useful responses above, I would like to share my solution that can be extended.
Here is the code that caused this crash in my application:
@Override
public void onListItemClicked(ListItem item) {
Bundle bundle = new Bundle();
bundle.putParcelable(SomeFragment.LIST_KEY, item);
Navigation.findNavController(recyclerView).navigate(R.id.action_listFragment_to_listItemInfoFragment, bundle);
}
A way to easily reproduce the bug is to tap with multiple fingers on the list of items where click on each item resolves in the navigation to the new screen (basically the same as people noted - two or more clicks in a very short period of time). I noticed that:
navigate invocation always works fine;navigate method resolve in IllegalArgumentException.From my point of view, this situation may appear very often. Since the repeating of code is a bad practice and it is always good to have one point of influence I thought of the next solution:
public class NavigationHandler {
public static void navigate(View view, @IdRes int destination) {
navigate(view, destination, /* args */null);
}
/**
* Performs a navigation to given destination using {@link androidx.navigation.NavController}
* found via {@param view}. Catches {@link IllegalArgumentException} that may occur due to
* multiple invocations of {@link androidx.navigation.NavController#navigate} in short period of time.
* The navigation must work as intended.
*
* @param view the view to search from
* @param destination destination id
* @param args arguments to pass to the destination
*/
public static void navigate(View view, @IdRes int destination, @Nullable Bundle args) {
try {
Navigation.findNavController(view).navigate(destination, args);
} catch (IllegalArgumentException e) {
Log.e(NavigationHandler.class.getSimpleName(), "Multiple navigation attempts handled.");
}
}
}
And thus the code above changes only in one line from this:
Navigation.findNavController(recyclerView).navigate(R.id.action_listFragment_to_listItemInfoFragment, bundle);
to this:
NavigationHandler.navigate(recyclerView, R.id.action_listFragment_to_listItemInfoFragment, bundle);
It even became a little bit shorter. The code was tested in the exact place where the crash occurred. Did not experience it anymore, and will use the same solution for other navigations to avoid the same mistake further.
Any thoughts are welcome!
What exactly causes the crash
Remember that here we work with the same navigation graph, navigation controller and back-stack when we use method Navigation.findNavController.
We always get the same controller and graph here. When navigate(R.id.my_next_destination) is called graph and back-stack changes almost instantly while UI is not updated yet. Just not fast enough, but that is ok. After back-stack has changed the navigation system receives the second navigate(R.id.my_next_destination) call. Since back-stack has changed we now operate relative to the top fragment in the stack. The top fragment is the fragment you navigate to by using R.id.my_next_destination, but it does not contain next any further destinations with ID R.id.my_next_destination. Thus you get IllegalArgumentException because of the ID that the fragment knows nothing about.
This exact error can be found in NavController.java method findDestination.
It occurs to me when I press the back button two times. At first, I intercept KeyListener and override KeyEvent.KEYCODE_BACK. I added the code below in the function named OnResume for the Fragment, and then this question/issue is solved.
override fun onResume() {
super.onResume()
view?.isFocusableInTouchMode = true
view?.requestFocus()
view?.setOnKeyListener { v, keyCode, event ->
if (event.action == KeyEvent.ACTION_DOWN && keyCode == KeyEvent.KEYCODE_BACK) {
activity!!.finish()
true
}
false
}
}
When it happens to me for a second time, and it's status is the same as the first one, I find that I maybe use the adsurd function. Let’s analyze these situations.
Firstly, FragmentA navigates to FragmentB ,then FragmentB navigates to FragmentA, then press back button... the crash appears.
Secondly, FragmentA navigates to FragmentB, then FragmentB navigates to FragmentC, FragmentC navigates to FragmentA, then press back button... the crash appears.
So I think when pressing back button, FragmentA will return to FragmentB or FragmentC, then it causes the login mess. Finally I find that the function named popBackStack can be used for back rather than navigate.
NavHostFragment.findNavController(this@TeacherCloudResourcesFragment).
.popBackStack(
R.id.teacher_prepare_lesson_main_fragment,false
)
So far, the problem is really solved.
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.
This happened to me, my issue was I was clicking a FAB on tab item fragment. I was trying to navigate from one of tab item fragment to another fragment.
But according to Ian Lake in this answer we have to use tablayout and viewpager, no navigation component support. Because of this, there is no navigation path from tablayout containing fragment to tab item fragment.
ex:
containing fragment -> tab layout fragment -> tab item fragment -> another fragment
Solution was to create a path from tab layout containing fragment to intended fragment
ex: path: container fragment -> another fragment
Disadvantage:
In my case I got that error when tried to navigate from another thread, in 50% of cases. Run the code on main thread helps
requireActivity().runOnUiThread {
findNavController().navigate(...)
}
In my case this occured when I accidentally added a + in action destination , and the crash only occured when I went to same fragment multiple times .
<action
android:id="@+id/action_to_profileFragment"
app:destination="@+id/profileFragment" />
Solution is to remove + from action destination, use only @id/profileFragment instead of @+id/profileFragment
<action
android:id="@+id/action_to_profileFragment"
app:destination="@id/profileFragment" />
In my case, I had multiple nav graph files and I was trying to move from 1 nav graph location to a destination in another nav graph.
For this we have to include the 2nd nav graph in the 1st one like this
<include app:graph="@navigation/included_graph" />
and add this to your action:
<action
android:id="@+id/action_fragment_to_second_graph"
app:destination="@id/second_graph" />
where second_graph is :
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/second_graph"
app:startDestination="@id/includedStart">
in the second graph.
More info here
It seems that mixing fragmentManager control of the backstack and Navigation Architecture control of the backstack can cause this issue also.
For example the original CameraX basic sample used fragmentManager backstack navigation as below and it appears as if it did not correctly interact with Navigation:
// Handle back button press
view.findViewById<ImageButton>(R.id.back_button).setOnClickListener {
fragmentManager?.popBackStack()
}
If you log the 'current destination' with this version before moving from the main fragment (the camera fragment in this case) and then log it again when you return to the main fragment, you can see from the id in the logs that the id is not the same. At a guess, the Navigation updated it when moving to the fragment and the fragmntManager did not then update it again when moving back. From the logs:
Before: D/CameraXBasic: currentDest?: androidx.navigation.fragment.FragmentNavigator$Destination@b713195
After: D/CameraXBasic: currentDest?: androidx.navigation.fragment.FragmentNavigator$Destination@9807d8f
The updated version of CameraX basic sample uses Navigation to return like this:
// Handle back button press
view.findViewById<ImageButton>(R.id.back_button).setOnClickListener {
Navigation.findNavController(requireActivity(), R.id.fragment_container).navigateUp()
}
This works correctly and the logs show the same id when back at the main fragment.
Before: D/CameraXBasic: currentDest?: androidx.navigation.fragment.FragmentNavigator$Destination@b713195
After: D/CameraXBasic: currentDest?: androidx.navigation.fragment.FragmentNavigator$Destination@b713195
I suspect the moral of the story, at least at this time, is to be very careful mixing Navigation with fragmentManager navigation.
Updated @Alex Nuts solution
If there is no action for particular fragment and want to navigate to fragment
fun NavController.navigateSafe(
@IdRes actionId: Int, @IdRes fragmentId: Int, args: Bundle? = null,
navOptions: NavOptions? = null, navExtras: Navigator.Extras? = null)
{
if (actionId != 0) {
val action = currentDestination?.getAction(actionId) ?: graph.getAction(actionId)
if (action != null && currentDestination?.id != action.destinationId) {
navigate(actionId, args, navOptions, navExtras)
}
} else if (fragmentId != 0 && fragmentId != currentDestination?.id)
navigate(fragmentId, args, navOptions, navExtras)
}
