[ViewPager2] Support NavHostFragment inside ViewPager2 [133640271]

Fixed

Bug

Status Update

No update yet.

Description

an...@gmail.com

created issue #1

May 27, 2019 12:43PM

Use case:
Would like to use an existing app layout and take benefit of offscreen screen "caching"

The issue
Currently if I attempt to use NavHostFragment in combination with ViewPager2 and FragmentStateAdapter I'll get the following runtime exception due to uninitialised containterViewId (stack trace below).

If I change FragmentStateAdapter.placeFragmentInViewHolder
From:

// { f:notAdded, v:notCreated, v:notAttached } -> add, create, attach
if (!shouldDelayFragmentTransactions()) {
scheduleViewAttach(fragment, container);
mFragmentManager.beginTransaction().add(fragment, "f" + holder.getItemId()).commitNow();
}

To:

// { f:notAdded, v:notCreated, v:notAttached } -> add, create, attach
if (!shouldDelayFragmentTransactions()) {
mFragmentManager.beginTransaction().add(container.getId(), fragment, "f" + holder.getItemId()).commitNow();
}

The issue is solved. Testing a couple of scenarios did not reveal any side effects, but as I have yet to familiarise myself with the details of the implementation I'm not sure if it will not have any negative side effects.

Happy to put up a PR for this, but would like to understand better why the fragment is being added this way in the current state of the adapter.

Stack trace:

java.lang.IllegalArgumentException: Must use non-zero containerViewId
at androidx.fragment.app.FragmentTransaction.replace(FragmentTransaction.java:223)
at androidx.fragment.app.FragmentTransaction.replace(FragmentTransaction.java:200)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:181)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:58)
at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:80)
at androidx.navigation.NavGraphNavigator.navigate(NavGraphNavigator.java:30)
at androidx.navigation.NavController.navigate(NavController.java:877)
at androidx.navigation.NavController.onGraphCreated(NavController.java:524)
at androidx.navigation.NavController.setGraph(NavController.java:482)
at androidx.navigation.NavController.setGraph(NavController.java:447)
at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:248)
at androidx.fragment.app.Fragment.performCreate(Fragment.java:2613)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:831)
at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1228)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1293)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2066)
at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1856)
at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1811)
at androidx.fragment.app.FragmentManagerImpl.execSingleAction(FragmentManagerImpl.java:1686)
at androidx.fragment.app.BackStackRecord.commitNow(BackStackRecord.java:293)
at androidx.viewpager2.adapter.FragmentStateAdapter.placeFragmentInViewHolder(FragmentStateAdapter.java:284)
at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:222)
at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:61)
at androidx.recyclerview.widget.RecyclerView.dispatchChildAttached(RecyclerView.java:7433)
at androidx.recyclerview.widget.RecyclerView$5.addView(RecyclerView.java:862)
at androidx.recyclerview.widget.ChildHelper.addView(ChildHelper.java:107)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:8478)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8436)
at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8424)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1641)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4040)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3757)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4310)

Comments

jg...@google.com <jg...@google.com> #2May 31, 2019 11:45AM

since these are in public API (:/) we need to do this in 1.2

jg...@google.com <jg...@google.com> #3May 31, 2019 11:46AM

since it is already marked as deprecated, we can probably do it by now.

an...@gmail.com <an...@gmail.com> #4Jun 2, 2019 10:03AM

Opening diff shortly

sample.zip

1.6 MB

Download

an...@gmail.com <an...@gmail.com> #5Jun 2, 2019 11:43AM

Project: platform/frameworks/support
Branch: androidx-master-dev

commit d576cbdc911cba16638a44fd8223391a90a07ef7
Author: Mike Nakhimovich <digitalbuddha@users.noreply.github.com>
Date: Tue Aug 11 09:30:34 2020

[GH] Hide deprecated internal API.

## Proposed Changes

* `RoomDatabase.java` has protected `mCallbacks` field which is leaking in the API docs, we should @Hide it.

## Testing

Test: Ran unit tests locally

## Issues Fixed

Fixes: 76109329

This is an imported pull request from

https://github.com/androidx/androidx/pull/61.

Resolves #61
Github-Pr-Head-Sha: 6440daa3a63752c7f9d5ba2a390248cd85bc634f
GitOrigin-RevId: fe92d8466a59b44b218b6ca3cbd57dcda17992f7

Change-Id: Id599cdf5b02b32bdae0166266fb7da967598fe92

A room/runtime/api/current.ignore
M room/runtime/api/current.txt
M room/runtime/api/public_plus_experimental_current.txt
M room/runtime/api/restricted_current.txt
M room/runtime/src/main/java/androidx/room/RoomDatabase.java

https://android-review.googlesource.com/1396827

sample2.zip

2.7 MB

Download

jg...@google.com <jg...@google.com> Jul 2, 2019 03:38PM

Assigned to jg...@google.com.

jg...@google.com <jg...@google.com> #6Aug 14, 2019 05:31PM

We've filed a bug on Navigation.

In the meantime, as a workaround, instead of creating a NavHostFragment directly as a page, create a regular Fragment subclass instance with a container inside it, and place NavHostFragment inside that container.
Container can be something simple, e.g. a FrameLayout with an id, e.g. generated by ViewCompat.generateId()

il...@google.com <il...@google.com> #7Aug 20, 2019 04:38PM

Note that the id on your FrameLayout should *not* use ViewCompat.generateId() as the ID needs to be stable across configuration changes. The issue filed against Navigation (

https://issuetracker.google.com/issues/139421197) has been fixed for the upcoming Navigation 2.2.0-alpha02 - when using that version of Navigation, you wouldn't have to make any modifications to your ViewPager2 adapter and it would work with any version of ViewPager2.

jg...@google.com <jg...@google.com> #8Sep 24, 2019 04:16PM

Marked as fixed.

Fixed in

https://developer.android.com/jetpack/androidx/releases/navigation#2.2.0-alpha02