so I'm using the android navigation component and I have a problem (2.2.0-rc04 version).
I have a welcomeFragment(wF). From wF I want to navigate to loginSellerFragment(lSF) which is in a different navigation graph. I also don't want to remove wF from backstack ( popUpTo, popUpToInclusive) when navigating to lSF because a user might wanna go back to it.
<fragment
android:id="@+id/welcomeFragment">
<action
android:id="@+id/action_welcomeFragment_to_nav_onboarding_seller"
app:launchSingleTop="true"
app:destination="@id/nav_onboarding_seller" />
</fragment>
After navigating to lSF the backstack looks like this : wF lSF
We're on lSF now, after login we want to go to feedFragment(fF) which again is in a separate graph, but this time we want to clear all the backstack, because if a user is logged in and presses back he wants the app to exit, not to take him back to wF or lSF, so I used popUpTo="@id/loginSellerFragment popUpToInclusive='true" in the action from lSF to fF.
<fragment
android:id="@+id/loginSellerFragment">
<action
android:id="@+id/action_login_to_seller"
app:destination="@+id/seller" . //this is the graph that has as firstDestination, feedFragment
app:launchSingleTop="true"
app:popUpTo="@id/loginSellerFragment"
app:popUpToInclusive="true" />
</fragment>
So in the backstack in this moment should be only fF because we removed everything up to lSF(lSF included)
The problem
When I'm on fF and press back, the app doesn't close, instead it takes me to wF ( wF should have been popped off the backstack already)
What I've tried
I've tried instead of popUpTo="@id/loginSellerFragment popUpToInclusive='true" to use popUpTo="@id/welcomeFragment popUpToInclusive='true" and it worked fine, but I'm pretty sure that this is not how it should be done. What am I missing here guys? Am I building the backstack wrong?
Also I've tried adding popUpTo="@id/welcomeFragment popUpToInclusive='true" after navigating from wF to lSF , but this will break my user experience, because I don't want the app to exit when I'm still in the login process.
Please note that all of this fragments are in separate graphs.
To navigate I use FragmentDirections e.g : findNavController.navigate(WelcomeFramgentDirections.actionXtoY())
UrosKekovic :
It's not easy to grasp how Navigation Component manipulates backstack when you are using popUpTo option.\nThe solution you mentioned in your question is correct:\nYou indeed should use popUpTo="@id/welcomeFragment" popUpToInclusive="true" instead of popUpTo="@id/loginSellerFragment" popUpToInclusive="true".\nI will try to explain why.\n\nWhen you launch your application, your backstack will be empty and welcomeFragment will be displayed.\n\nWhen you navigate from welcomeFragment to loginSellerFragment, you will have welcomeFragment in your backstack.\n\nThan if you login, you will navigate from loginSellerFragment to feedFragment, and in backstack you will have loginSellerFragment and welcomeFragment.\n\n\nSince you used popUpTo="@id/welcomeFragment", aplication will start to pop (remove) fragments from your backstack until it reaches welcomeFragment. The welcomeFragment will be also removed since we used popUpToInclusive="true".\nBackstack should behave like FILO (First In Last Out) stack, so it will remove fragments in this manner:\nFirst the top fragment will be removed and that is loginSellerFragment.\nNext, welcomeFragment will be the top fragment. Since we need to pop up fragments until we reach welcomeFragment this is where we stop, but welcomeFragment will be also removed because of popUpToInclusive="true" and your backstack will be empty.\nIf you try to navigate back from welcomeFragment, you will exit app because your backstack is empty.\nI hope that this helps. You could also read more about stack data structure.",
2020-01-22T15:16:56