[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

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

commit b90079595f33f58fece04026a97faa0d243acdb1
Author: Yuichi Araki <yaraki@google.com>
Date: Wed Sep 18 16:55:49 2019

Change the way to detect mismatch between POJO and query

This fixes cursor mismatch warnings with expandProjection.

Bug: 140759491
Test: QueryMethodProcessorTest
Change-Id: I7659002e5e0d1ef60fc1af2a625c0c36da0664d8

M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt
M room/compiler/src/test/kotlin/androidx/room/processor/QueryMethodProcessorTest.kt
M room/compiler/src/test/kotlin/androidx/room/testing/TestProcessor.kt

https://android-review.googlesource.com/1123258

https://goto.google.com/android-sha1/b90079595f33f58fece04026a97faa0d243acdb1

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

The following changes were cherrypicked through Coastguard (

https://android-build.googleplex.com/coastguard/)
Release Track: (

https://android-build.googleplex.com/coastguard/dashboard/6093116828680192/#/cherrypickHistory/all)
Created: 2019-10-14 17:23:42.610596+00:00
Changes: aosp/1123258

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

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

commit bdde5a1a970ddc9007b28de4aa29d60ffa588f08
Author: Yigit Boyar <yboyar@google.com>
Date: Thu Apr 16 16:47:05 2020

Re-factor how errors are dismissed when query is re-written

This CL changes how we handle errors/warnings if query is
re-written.
There was a bug in expandProjection where we would report warnings
for things that Room already fixes automatically (

b/140759491

).
The solution to that problem (I7659002e5e0d1ef60fc1af2a625c0c36da0664d8)
solved it by deferring validating of columns until after re-write
decision is made. Unfortunately, this required changing PojoRowAdapter
to have a dummy mapping until it is validating, make it hard to use
as it does have a non-null mapping which is not useful.

This CL partially reverts that change and instead rely on the log
deferring logic we have in Context. This way, we don't need to break
the stability of PojoRowAdapter while still having the ability to
drop warnings that room fixes. This will also play nicer when we
have different query re-writing options that can use more information
about the query results.

Bug: 153387066
Bug: 140759491
Test: existing tests pass
Change-Id: I2ec967c763d33d7a3ff02c1a13c6953b460d1e5f

M room/compiler/src/main/kotlin/androidx/room/log/RLog.kt
M room/compiler/src/main/kotlin/androidx/room/processor/QueryMethodProcessor.kt
M room/compiler/src/main/kotlin/androidx/room/solver/TypeAdapterStore.kt
M room/compiler/src/main/kotlin/androidx/room/solver/query/result/PojoRowAdapter.kt

https://android-review.googlesource.com/1288456

sample.zip

1.6 MB

Download

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

Modified the sample a bit to include some state saving. For a simple rotations, backgrounding and foregrounding the app I could not see anything in the first couple of runs. If you could also please give it a go and let me know what sequence of events reveal any issues I'd greatly appreciate it.

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