Hi there, I have a question about navigation compo...

# android

[Joao Birk]

Hi there, I have a question about navigation components and navigating from one bottom sheet to another bottom sheet.
On Bottom Sheet A I have an option that does the following:

dismiss()
findNavController().navigate(
    R.id.action_bottom_sheet_b,
    bundleOf(...)
)

It opens the Bottom Sheet B without any problem, but if I rotate the screen I get a crash:

java.lang.IllegalStateException
DialogFragment NUM doesn't exist in the FragmentManager

If I move the dismiss after the navigate, Bottom Sheet B doesnt show up. Seems they are in the same transaction and therefore bottom sheet B gets dismised as well.

Here is my navigation.xml

<dialog
    android:id="@+id/bottom_sheet_a"
    android:name="...BottomSheetA"
    tools:layout="@layout/dialog_bottom_sheet_a">

    <action
        android:id="@+id/action_bottom_sheet_b"
        app:destination="@id/bottom_sheet_b"/>

</dialog>

I found this on stack: https://stackoverflow.com/questions/56647476/why-dialog-does-not-have-a-navcontroller-missing
And this: https://issuetracker.google.com/issues/134089818 which seems got resolved in 2.1.0-alpha06

But not sure it's the same issue. I'm using 2.3.0.

If I use child childFragmentManager.beginTransaction().show() to show bottom sheet A instead of findNavController().navigate() , bottom sheet B gets displayed fine, no crash either.

Any ideas of how to fix this?

[Ian Lake]

dismiss() is asynchronous and doesn't inform the NavController until after the navigate() already updates the state. You want findNavController().popBackStack() which does synchronously update the NavController instead. Or just add a popUpTo to your action: https://developer.android.com/guide/navigation/navigation-navigate#pop

[Joao Birk]

Gotcha! Thanks for the help.