IssueTracker

Hi, thanks for reporting. Should be an easy fix!

I'm guessing it should work find until ~ 2^23 items = ~ 8M items. How did you come across this bug? Do you have a ViewPager2 with that many items?

Hi, good to hear that.

We have an implementation of RecyclerView.Adapter that supports "infinite looping". So when the infinite looping is enabled, the adapter's getItemCount() reports Int.MAX_VALUE items. We also call setCurrentItem to somewhere in the middle of item count on the ViewPager2, so that's how we got that far.

For future reference: first item for which it fails is probably when mCurrentItem = (1 << 25) + 2

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

commit 2e9f35536432bed0677171c8ae59b4f67850915a
Author: Jelle Fresen <jellefresen@google.com>
Date:   Fri Jul 12 14:26:10 2019

    Use double instead of float for decimal positions
   
    A position ranges from 0 to Integer.MAX_VALUE, but floats only have a 23
    bit mantissa. Values over 2^23 are rounded to a nearby value.
   
    Solve this by using double instead of float when we need to represent a
    position with a fractional component. A double has a mantissa of 52 bit
    and can therefore represent all 2^32 possible int values.
   
    Bug: 134858960
    Test: ./gradlew viewpager2:cC
    Change-Id: I08b97df6fac600caa83366ccab8671541e2c1e7f

A       viewpager2/src/androidTest/java/androidx/viewpager2/test/ui/SparseAdapter.kt
M       viewpager2/src/androidTest/java/androidx/viewpager2/widget/FakeDragTest.kt
M       viewpager2/src/androidTest/java/androidx/viewpager2/widget/OffscreenPageLimitTest.kt
M       viewpager2/src/androidTest/java/androidx/viewpager2/widget/PageChangeCallbackTest.kt
M       viewpager2/src/androidTest/java/androidx/viewpager2/widget/PageTransformerTest.kt
M       viewpager2/src/androidTest/java/androidx/viewpager2/widget/SetItemWhileScrollInProgressTest.kt
M       viewpager2/src/main/java/androidx/viewpager2/widget/ScrollEventAdapter.java
M       viewpager2/src/main/java/androidx/viewpager2/widget/ViewPager2.java

https://android-review.googlesource.com/1014538
https://goto.google.com/android-sha1/2e9f35536432bed0677171c8ae59b4f67850915a

Fixed in now released beta03 - https://developer.android.com/jetpack/androidx/releases/viewpager2#1.0.0-beta03

I can confirm I can repro this and will try to provide a workaround / fix soon.
Big thanks for the sample app, repro steps and research info. Super appreciated!

The easiest workaround would involve copying FragmentStateAdapter and FragmentViewHolder into your project, and in FragmentStateAdapter adding ensureFragment(holder.getAdapterPosition()) as the first line of placeFragmentInViewHolder method. Attached as a patch to your sample app.

We'll work on a proper fix. Might unblock you in the meantime though. Thanks again for reporting and a sample app.

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

commit 07cadad5116ff71ab161a8ef3433679d89530405
Author: Jakub Gielzak <jgielzak@google.com>
Date:   Mon Jul 29 15:17:08 2019

    Fix for FragmentStateAdapter transient state issue
   
    Fixes a crash when a ViewHolder which has gone through
    onFailedToRecycleView is shown again violating Adapter's design
    assumptions.
   
    Bug: 134246546
    Test: TransientStateFragmentTest
    Test: ./gradlew viewpager2:connectedCheck
   
    Change-Id: Ieb166c6fb48907cbb7aa46ab87a3ae4cc29591a6

A       viewpager2/src/androidTest/java/androidx/viewpager2/widget/TransientStateFragmentTest.kt
M       viewpager2/src/main/java/androidx/viewpager2/adapter/FragmentStateAdapter.java

https://android-review.googlesource.com/1092796
https://goto.google.com/android-sha1/07cadad5116ff71ab161a8ef3433679d89530405

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

commit a35a5180df0b98c4af4a4e119388f7d70d27ade4
Author: Jakub Gielzak <jgielzak@google.com>
Date:   Tue Jul 30 17:27:14 2019

    FragmentStateAdapter transient state fix follow-up
   
    Follow-up to Ieb166c6fb48907cbb7aa46ab87a3ae4cc29591a6:
    * Disabled tests on API < 16
    * Updated a comment
   
    Bug: 134246546
    Test: TransientStateFragmentTest
    Test: ./gradlew viewpager2:connectedCheck
   
    Change-Id: Id27c1267d4fc75c41849291322952fc1ea0e8d0d

M       viewpager2/src/androidTest/java/androidx/viewpager2/widget/TransientStateFragmentTest.kt
M       viewpager2/src/main/java/androidx/viewpager2/adapter/FragmentStateAdapter.java

https://android-review.googlesource.com/1093437
https://goto.google.com/android-sha1/a35a5180df0b98c4af4a4e119388f7d70d27ade4

The fix is now in place and should come out in the next release.

Fixed in now released beta03 - https://developer.android.com/jetpack/androidx/releases/viewpager2#1.0.0-beta03

I can't reproduce this myself but I get this issue in production on Xiaomi running Android 10 with ViewPager2 1.0.0 stable release. Any idea what could cause it now?

Hi, could you share the stack trace?

Here's an issue I created since this was marked as fixed: https://issuetracker.google.com/issues/147688910

I am facing this issue in 1.0.0 release

Fatal Exception: java.lang.IllegalStateException
Design assumption violated.
androidx.viewpager2.adapter.FragmentStateAdapter.placeFragmentInViewHolder + 287 (FragmentStateAdapter.java:287)
androidx.viewpager2.adapter.FragmentStateAdapter$1.onLayoutChange + 190 (FragmentStateAdapter.java:190)
android.view.View.layout + 21131 (View.java:21131)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
androidx.recyclerview.widget.RecyclerView$LayoutManager.layoutDecoratedWithMargins + 9587 (RecyclerView.java:9587)
androidx.recyclerview.widget.LinearLayoutManager.layoutChunk + 1685 (LinearLayoutManager.java:1685)
androidx.recyclerview.widget.LinearLayoutManager.fill + 1587 (LinearLayoutManager.java:1587)
androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren + 665 (LinearLayoutManager.java:665)
androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2 + 4134 (RecyclerView.java:4134)
androidx.recyclerview.widget.RecyclerView.dispatchLayout + 3851 (RecyclerView.java:3851)
androidx.recyclerview.widget.RecyclerView.onLayout + 4404 (RecyclerView.java:4404)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
androidx.viewpager2.widget.ViewPager2.onLayout + 527 (ViewPager2.java:527)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
androidx.constraintlayout.widget.ConstraintLayout.onLayout + 1915 (ConstraintLayout.java:1915)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
android.widget.FrameLayout.layoutChildren + 323 (FrameLayout.java:323)
android.widget.FrameLayout.onLayout + 261 (FrameLayout.java:261)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
android.widget.LinearLayout.setChildFrame + 1828 (LinearLayout.java:1828)
android.widget.LinearLayout.layoutVertical + 1656 (LinearLayout.java:1656)
android.widget.LinearLayout.onLayout + 1565 (LinearLayout.java:1565)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
android.widget.FrameLayout.layoutChildren + 323 (FrameLayout.java:323)
android.widget.FrameLayout.onLayout + 261 (FrameLayout.java:261)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
android.widget.LinearLayout.setChildFrame + 1828 (LinearLayout.java:1828)
android.widget.LinearLayout.layoutVertical + 1656 (LinearLayout.java:1656)
android.widget.LinearLayout.onLayout + 1565 (LinearLayout.java:1565)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
android.widget.FrameLayout.layoutChildren + 323 (FrameLayout.java:323)
android.widget.FrameLayout.onLayout + 261 (FrameLayout.java:261)
com.android.internal.policy.DecorView.onLayout + 883 (DecorView.java:883)
android.view.View.layout + 21112 (View.java:21112)
android.view.ViewGroup.layout + 6400 (ViewGroup.java:6400)
android.view.ViewRootImpl.performLayout + 3368 (ViewRootImpl.java:3368)
android.view.ViewRootImpl.performTraversals + 2809 (ViewRootImpl.java:2809)
android.view.ViewRootImpl.doTraversal + 1815 (ViewRootImpl.java:1815)
android.view.ViewRootImpl$TraversalRunnable.run + 8228 (ViewRootImpl.java:8228)
android.view.Choreographer$CallbackRecord.run + 995 (Choreographer.java:995)
android.view.Choreographer.doCallbacks + 807 (Choreographer.java:807)
android.view.Choreographer.doFrame + 739 (Choreographer.java:739)
android.view.Choreographer$FrameDisplayEventReceiver.run + 981 (Choreographer.java:981)
android.os.Handler.handleCallback + 873 (Handler.java:873)
android.os.Handler.dispatchMessage + 99 (Handler.java:99)
android.os.Looper.loop + 226 (Looper.java:226)
android.app.ActivityThread.main + 7212 (ActivityThread.java:7212)
java.lang.reflect.Method.invoke (Method.java)
com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run + 576 (RuntimeInit.java:576)
com.android.internal.os.ZygoteInit.main + 956 (ZygoteInit.java:956)

I also facing this issue in 1.0.0 release

finally I do can reproduce this bugs, please check this! https://stackoverflow.com/a/63114195/8868638.

Occurred in 1.0.0

java.lang.IllegalStateException: Design assumption violated.
        at androidx.viewpager2.adapter.FragmentStateAdapter.placeFragmentInViewHolder(FragmentStateAdapter.java:287)
        at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:276)
        at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:67)
        at androidx.recyclerview.widget.RecyclerView.dispatchChildAttached(RecyclerView.java:7556)
        at androidx.recyclerview.widget.RecyclerView$5.addView(RecyclerView.java:860)
        at androidx.recyclerview.widget.ChildHelper.addView(ChildHelper.java:107)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:8601)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8559)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8547)
        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:4134)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
        at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at androidx.viewpager2.widget.ViewPager2.onLayout(ViewPager2.java:527)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at com.google.android.material.appbar.HeaderScrollingViewBehavior.layoutChild(HeaderScrollingViewBehavior.java:148)
        at com.google.android.material.appbar.ViewOffsetBehavior.onLayoutChild(ViewOffsetBehavior.java:43)
        at com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior.onLayoutChild(AppBarLayout.java:1892)
        at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:918)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at androidx.drawerlayout.widget.DrawerLayout.onLayout(DrawerLayout.java:1231)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:573)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:508)
        at android.view.View.layout(View.java:15596)
        at android.view.ViewGroup.layout(ViewGroup.java:4966)
        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:

version 1.0.0-beta03


java.lang.IllegalStateException: Design assumption violated.
        at androidx.viewpager2.adapter.FragmentStateAdapter.placeFragmentInViewHolder(FragmentStateAdapter.java:287)
        at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:276)
        at androidx.viewpager2.adapter.FragmentStateAdapter.onViewAttachedToWindow(FragmentStateAdapter.java:67)
        at androidx.recyclerview.widget.RecyclerView.dispatchChildAttached(RecyclerView.java:7867)
        at androidx.recyclerview.widget.RecyclerView$5.addView(RecyclerView.java:893)
        at androidx.recyclerview.widget.ChildHelper.addView(ChildHelper.java:107)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:8902)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8860)
        at androidx.recyclerview.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:8848)
        at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1645)
        at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1591)
        at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:668)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:4255)
        at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:4010)
        at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4578)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at androidx.viewpager2.widget.ViewPager2.onLayout(ViewPager2.java:527)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at com.android.internal.policy.DecorView.onLayout(DecorView.java:804)
        at android.view.View.layout(View.java:23219)
        at android.view.ViewGroup.layout(ViewGroup.java:6532)
        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3686)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:3144)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:2115)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8582)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:975)
        at android.view.Choreographer.doCallbacks(Choreographer.java:799)
        at android.view.Choreographer.doFrame(Choreographer.java:734)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:960)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:236)
        at android.app.ActivityThread.main(ActivityThread.java:7864)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:620)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1011)

The cause is getItemId return the  duplicate id.
I find self test stable reproduction.