Navigation component Kotlin - cannot be found from the current destination

Question

I have a fragment A,B,C. Its okay when navigating from A -> B, but from B -> C it crashes.

Here is my Navigation

Here is my navigation code

 categoryProductItemListAdapter.setOnItemClickListener {
        val action = CategoryProductItemsDirections.actionCategoryProductItems2ToProductItem(null, it)
        navController = Navigation.findNavController(requireView())
        navController?.navigateUp()
        navController?.navigate(action)
    }

Here is the XML code for the destination to productItem

<fragment
    android:id="@+id/categoryProductItems2"
    android:name="com.sample.store.main.dashboard.ui.ui.home.categoryitems.CategoryProductItems"
    android:label="CategoryProductItems"
    tools:layout="@layout/fragment_category_product_items">
    <argument
        android:name="category_global"
        app:argType="com.sample.store.data.globalmodels.response.categories.Category" />
    <action
        android:id="@+id/action_categoryProductItems2_to_productItem"
        app:destination="@id/productItem"
        app:enterAnim="@anim/enter_from_right"
        app:exitAnim="@anim/exit_to_right"
        app:popEnterAnim="@anim/fragment_open_enter"
        app:popExitAnim="@anim/fragment_fade_exit" />
</fragment>

And here is the error:

java.lang.IllegalArgumentException: Navigation action/destination com.sample.store.full:id/action_categoryProductItems2_to_productItem cannot be found from the current destination Destination(id/navigation_home) label=Home class=com.sample.store.main.dashboard.ui.ui.home.mainui.HomeFragment

I don't know what happened, but it seems that the navController is looking for the "navigation_home"

@Cyd remove that line ` navController?.navigateUp()` may resolve your problem — asad mahmood, Sep 09 '20 at 11:23

score 33 · Answer 1 · answered Jun 02 '21 at 20:01

This is more a heads up than an answer. But I hope it helps.

Summary: (As others have already said:) Successive calls to Navigation functions are the reason of most of these exceptions.

Given how the android components are structured, specially how MediatorLiveData works, people may sometimes want to join data nodes in a single observable data holder (LiveData).

If an observation of this mediator is linked to dynamic Navigation functions, bugs will undoubtedly appear.

The reason is that sources may change a LiveData value a successive number of times equal to the amount of sources connected to the Mediator.

This is a perfectly good idea, BUT. Repeated changes to the NavController will definitely result in undesirable outcomes.

This may include:

popping the backStack twice.
Going from A -> B twice in a row giving an exception of A not found
the second time.

This is a big testing problem specially since the issue of one Fragment may cascade to the underlaying stacks, and so when an exception of Direction not found may arise in one Fragment, The real culprit may be found on the Fragment on TOP of the one giving the exception.

In reality this would be easily solved by creating a self cancelling thread executor scheduled.cancel(true); with a delaying tolerance on the mediatorLiveData itself (the onChange to be precise, not the setValue() since eager inner state updates are the entire and only purpose/joke of the mediator IMHO (sorry, no postValue() allowed!)).

Not to mention that the mediator itself is an incomplete component...

Another easier approach is to make sure that onChange calls from a MutableLiveData are performed if and only if !Object::Equals, and prevent repeating calls to onChange() which is still a testament of the incompleteness of the MediatorLiveData/LiveData. (Just be extremely careful with Lists)

At all costs avoid performing successive calls to a NavController, and if you somehow MUST, then a delayed runnable may be your only way to achieve it.

thanks for pointing that out. i was listening to a flow for navigation changes and was subscribing to it multiple times as i started listening in Fragments onViewCreated (which is called multiple times) — cwiesner, Mar 03 '22 at 10:48

score 18 · Accepted Answer · answered Sep 09 '20 at 06:46

18

Firstly you should not pass requireView() when trying to retrieve your Nav controller - navController = Navigation.findNavController(requireView()). You should be passing the actual Navigation Host Fragment instance.

Secondly the issue is being caused because you are trying to call a Navigation path from B -> C, when on fragment A.

Your direction path is from B -> C

val action = CategoryProductItemsDirections.actionCategoryProductItems2ToProductItem(null, it)

But you navigate up first so you are actually now on Fragment A when trying to execute the navigation:

navController?.navigateUp()
navController?.navigate(action)

answered Sep 09 '20 at 06:46

Indiana

534
5
18

4

When dealing with nested fragments like a ViewPager you can easily make the mistake of trying to navigate from a nested page to another fragment when in fact the navigation must be from the ViewPager fragment to the destination fragment. – Jeffrey Jul 23 '21 at 00:47
Interesting comment, buy not sure what relevance a view pager has to this post / question? There's no mention of a view pager being used – Indiana Jul 24 '21 at 05:53
1

Your answer helped me solve the problem I mentioned in the comment. That is, trying to navigate from a destination that you are not currently on. – Jeffrey Jul 25 '21 at 03:04

vishnu benny · Answer 3 · 2022-02-18T14:56:28.063

10

I have created an extension function to check the feasibility of starting an action from the current destination.

fun NavController.navigateSafe(@IdRes resId: Int, args: Bundle? = null) {
val destinationId = currentDestination?.getAction(resId)?.destinationId.orEmpty()
currentDestination?.let { node ->
    val currentNode = when (node) {
        is NavGraph -> node
        else -> node.parent
    }
    if (destinationId != 0) {
        currentNode?.findNode(destinationId)?.let { navigate(resId, args) }
    }
}}

And the orEmpty() part is extension over Int? as follows:

fun Int?.orEmpty(default: Int = 0): Int {
    return this ?: default
}

edited Feb 18 '22 at 14:56

answered May 20 '21 at 05:29

vishnu benny

774
7
14

1

val destinationId = currentDestination?.getAction(resId)?.destinationId.orEmpty() In this line the last .orEmpty() is red. i dont know why. if (destinationId != EMPTY_INT) { currentNode?.findNode(destinationId)?.let { navigate(resId, args) } } and in this condition EMPTY_INT is red which value will be check there. guide me – Syed Rafaqat Hussain Aug 13 '21 at 06:10
@SyedRafaqatHussain looks like .orEmpty() is some extention which apply int value to destinationId. You can use destinationId as nullable property without this extention call and just change check to if (destinationId != null) – Sviatoslav Zaitsev Feb 17 '22 at 22:09
1

very good solution. – Luiz Alegria Apr 27 '22 at 19:49
But when you pass a destination resId instead of action resId, this logic is not working, because `currentDestination?.getAction(resId)` is returning null. – Shefchenko May 17 '22 at 15:02

score 1 · Answer 4 · answered Mar 22 '22 at 06:28

This kind of error appears mostly in a list of elements and clicking on a item triggers navigation.

I solved with this code, on item click before calling navigate function I'll check whether the current destination is the intended one as,

val currentDestinationIsHome = this.findNavController().currentDestination == this.findNavController().findDestination(R.id.nav_home)
val currentDestinationIsDetail = this.findNavController().currentDestination == this.findNavController().findDestination(R.id.nav_detail)

if(currentDestinationIsHome && !currentDestinationIsDetail){
    .... 
    // perform navigation
}

This ensures navigation is only done when the destinations are in a legal state. [No IllegalStateException ... :)) ]

score 0 · Answer 5 · answered Nov 10 '20 at 18:42

For my case, I resolve the problem by replacing -

 <action
    android:id="@+id/action_categoryProductItems2_to_productItem"
    app:destination="@id/productItem"
    app:enterAnim="@anim/enter_from_right"
    app:exitAnim="@anim/exit_to_right"
    app:popEnterAnim="@anim/fragment_open_enter"
    app:popExitAnim="@anim/fragment_fade_exit"/>

with

 <action
    android:id="@+id/action_categoryProductItems2_to_productItem"
    app:destination="@id/productItem"
    app:enterAnim="@anim/enter_from_right"
    app:exitAnim="@anim/exit_to_right"
    app:popEnterAnim="@anim/fragment_open_enter"
    app:popExitAnim="@anim/fragment_fade_exit"
    app:popUpToInclusive="true" /* If true then also remove the destination from stack while popup */
    app:popUpTo="@id/navigation_home"/>  /*The fragment where to land again from destination*/

score 0 · Answer 6 · answered Aug 26 '21 at 06:21

0

For my case,I resolve the problem by replacing

implementation "android.arch.navigation:navigation-fragment-ktx:1.0.0"

with

implementation "androidx.navigation:navigation-fragment-ktx:2.3.5"

answered Aug 26 '21 at 06:21

Toby Lindholm

1
1

score -1 · Answer 7 · answered Sep 09 '20 at 08:26

You need to set defaultNavHost="true". Like in this example:

<LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">
            <androidx.fragment.app.FragmentContainerView
                android:id="@+id/myNavHostFragment"
                android:name="androidx.navigation.fragment.NavHostFragment"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:defaultNavHost="true"
                app:navGraph="@navigation/navigation_layout" />
        </LinearLayout>

Also dont forget to set the home activity in your navigation component.

Navigation component Kotlin - cannot be found from the current destination

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