FragmentStatePagerAdapter crashes when replacing fragments using new behavior [137209870]

Fixed

Bug

Status Update

No update yet.

Description

pe...@airbnb.com

created issue #1

Jul 11, 2019 03:26AM

Component used: Fragment
Version used: 1.1.0-rc01 (part of AppCompat 1.1.0-rc01)
Devices/Android versions reproduced on: API 28 x86 emulator and Pixel 1

When using the new `BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT` behavior on a `FragmentStatePagerAdapter`, along with `getItemPosition()` returning `POSITION_NONE`, the app crashes when calling `notifyDataSetChanged()` on the adapter. We are using this paradigm to replace all of the fragments in the adapter.

Here's what seems to be happening. All of the fragments are removed in a fragment transaction (`ViewPager` calls `FragmentStatePagerAdapter#finishUpdate()` once the fragments are removed). Then the new fragments are instantiated and added to a new fragment transaction. The `ViewPager` then calls `setPrimaryItem` which tries to set the max lifecycle on the `mCurrentPrimaryItem`. However, this `mCurrentPrimaryItem` is still referencing the old fragment that was removed in a separate transaction, which causes the crash. It seems like the `mCurrentPrimaryItem` should be nulled out if it is removed from the adapter.

I've attached a sample project and GIF. To reproduce, just launch the app and press the `Replace Fragments` action button. Here's the error stacktrace:

2019-07-10 20:03:16.876 32176-32176/com.example.android.horizontalpaging E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.horizontalpaging, PID: 32176
java.lang.IllegalArgumentException: Cannot setMaxLifecycle for Fragment not attached to FragmentManager FragmentManager{9187988 in HostCallbacks{ba35f21}}
at androidx.fragment.app.BackStackRecord.setMaxLifecycle(BackStackRecord.java:244)
at androidx.fragment.app.FragmentStatePagerAdapter.setPrimaryItem(FragmentStatePagerAdapter.java:234)
at androidx.viewpager.widget.ViewPager.populate(ViewPager.java:1234)
at androidx.viewpager.widget.ViewPager.setCurrentItemInternal(ViewPager.java:669)
at androidx.viewpager.widget.ViewPager.setCurrentItemInternal(ViewPager.java:631)
at androidx.viewpager.widget.ViewPager.dataSetChanged(ViewPager.java:1086)
at androidx.viewpager.widget.ViewPager$PagerObserver.onChanged(ViewPager.java:3097)
at androidx.viewpager.widget.PagerAdapter.notifyDataSetChanged(PagerAdapter.java:291)
at com.example.android.horizontalpaging.MainActivity.onOptionsItemSelected(MainActivity.java:67)
at android.app.Activity.onMenuItemSelected(Activity.java:3544)
at androidx.fragment.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:384)
at com.android.internal.policy.PhoneWindow.onMenuItemSelected(PhoneWindow.java:1237)
at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:776)
at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:148)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:923)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:913)
at android.widget.ActionMenuView.invokeItem(ActionMenuView.java:617)
at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:147)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6718)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

FragmentStatePagerCrash.gif

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HorizontalPaging.zip

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Comments

pe...@airbnb.com <pe...@airbnb.com> #2Jul 11, 2019 03:27AM

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

commit 3ba83f0a97f9cb645b95dc6a5b2ac02b4f159a23
Author: Ian Lake <ilake@google.com>
Date: Thu Mar 21 14:19:27 2019

Remove argument Bundle from FragmentFactory#instantiate

Provide a clearer separation between what
instantiate() is supposed to do (just
construct the class instance) versus what is
the responsibility of the caller (set the
arguments on the resulting Fragment).

As arguments can change at any time, it doesn't
make as much sense to use them at instantiation
time.

Test: tests still pass
Fixes: 128836103
Change-Id: I8018f4963ace5e58144ed1596c3b1e0b46638a7e

M fragment/api/1.1.0-alpha06.txt
M fragment/api/current.txt
M fragment/src/androidTest/java/androidx/fragment/app/FragmentFactoryTest.kt
M fragment/src/main/java/androidx/fragment/app/Fragment.java
M fragment/src/main/java/androidx/fragment/app/FragmentFactory.java
M fragment/src/main/java/androidx/fragment/app/FragmentManagerImpl.java
M fragment/src/main/java/androidx/fragment/app/FragmentState.java
M fragment/src/main/java/androidx/fragment/app/FragmentTabHost.java
M fragment/testing/api/1.1.0-alpha06.txt
M fragment/testing/api/current.txt
M fragment/testing/src/androidTest/java/androidx/fragment/app/testing/FragmentScenarioTest.kt
M fragment/testing/src/main/java/androidx/fragment/app/testing/FragmentScenario.java
M fragment/testing/src/main/java/androidx/fragment/app/testing/FragmentScenario.kt
M navigation/fragment/src/androidTest/java/androidx/navigation/fragment/FragmentNavigatorTest.kt
M navigation/fragment/src/main/java/androidx/navigation/fragment/FragmentNavigator.java
M preference/build.gradle
M preference/src/main/java/androidx/preference/PreferenceFragmentCompat.java
M samples/Support4Demos/src/main/java/com/example/android/supportv4/app/FragmentTabsPager.java
M samples/SupportLeanbackDemos/src/main/java/com/example/android/leanback/SearchSupportActivity.java
M samples/SupportPreferenceDemos/src/main/java/com/example/android/supportpreference/FragmentSupportPreferencesLeanback.java
M samples/SupportPreferenceDemos/src/main/java/com/example/androidx/preference/LeanbackPreferences.java

https://android-review.googlesource.com/932496

https://goto.google.com/android-sha1/3ba83f0a97f9cb645b95dc6a5b2ac02b4f159a23

il...@google.com <il...@google.com> Jul 11, 2019 02:16PM

Assigned to jb...@google.com.

ap...@google.com <ap...@google.com> #3Jul 11, 2019 10:54PM

Woot woot

jb...@google.com <jb...@google.com> #4Jul 11, 2019 10:55PM

Marked as fixed.

We've deprecated the FragmentFactory.instantiate(ClassLoader, String, android.os.Bundle?) method and switched all of our code to use the new instantiate(ClassLoader, String) for Fragment 1.1.0-alpha06.

The deprecated API will be removed in a later release.

an...@google.com <an...@google.com> #5Jul 12, 2019 09:20PM

The following changes were cherrypicked through Coastguard (

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

https://android-build.googleplex.com/coastguard/dashboard/6552735953321984/#/cherrypickHistory/all)
Created: 2019-07-12 21:19:25.239291+00:00
Changes: aosp/1014732

da...@gmail.com <da...@gmail.com> #6Jul 17, 2019 04:53AM

I also experienced this issue and seeing as it's marked as fixed I tried adding the fragment 1.1.0-SNAPSHOT, however it wasn't fixed there.

I tried the fragment 1.2.0-SNAPSHOT and it was fixed there.

So temp fix was to add the snapshots repo and manually add the fragment dependency:

repositories {
maven {
url '

https://ci.android.com/builds/submitted/5724286/androidx_snapshot/latest/repository/'
}
}
dependencies {
implementation 'androidx.fragment:fragment:1.2.0-SNAPSHOT'
}

So my question is what's the timeline for a 1.1.0-rc02 release? And when will appcompat be updated reference this?

il...@google.com <il...@google.com> #7Jul 17, 2019 05:22PM

Fragment 1.1.0-rc02 is out right now, actually.

AppCompat 1.1.0 stable will depend on Fragment 1.1.0 stable, which will include this change.

ya...@gmail.com <ya...@gmail.com> #8Jul 21, 2019 05:17PM

We are targeting sdk 28

I notice the release note for androidx.appcompat:appcompat:1.1.0-rc01 stated

Note: This version will only compile against the Q Beta 4 SDK

Will androidx.appcompat:appcompat:1.1.0-rc02, which contains this bug fix, have this limitation too?

Can an app targeting sdk 28 using upcoming androidx.appcompat:appcompat:1.1.0-rc02 ?

Thank you.

il...@google.com <il...@google.com> #9Jul 22, 2019 05:00AM

Re #8 - you'll need to *compile* against API 29 (that'll be true for 1.1.0-rc01 and all future versions of AppCompat), but there's no requirement to *target* API 29 - those are entirely different things as per

https://medium.com/androiddevelopers/picking-your-compilesdkversion-minsdkversion-targetsdkversion-a098a0341ebd