我自己无法重现此问题，但我注意到小米 MI 9 运行Android 10的生产中存在此问题。以下是我使用的ViewPager2和RecyclerView版本：
androidx.recyclerview:recyclerview:1.1.0
androidx.viewpager2:viewpager2:1.0.0
这是堆栈跟踪：
Fatal Exception: 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.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1643)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:675)
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:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
at androidx.viewpager2.widget.ViewPager2.onLayout(ViewPager2.java:527)
at android.view.View.layout(View.java:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
at android.view.View.layout(View.java:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
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:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
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:803)
at android.view.View.layout(View.java:21963)
at android.view.ViewGroup.layout(ViewGroup.java:6317)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3144)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2654)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1782)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7785)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1031)
at android.view.Choreographer.doCallbacks(Choreographer.java:854)
at android.view.Choreographer.doFrame(Choreographer.java:789)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1016)
at android.os.Handler.handleCallback(Handler.java:883)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7520)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)
我不确定这是从我的代码中触发的，因为堆栈跟踪不是很清楚。此外，根据 Google 问题跟踪器，这已在 viewpager2：1.0.0-beta03 中得到解决：https://issuetracker.google.com/issues/134246546 在这里提交，但在我的情况下并不完全。这是另一篇具有相同问题的帖子，没有太多有用的答案：FragmentStateAdapter 抛出 java.lang.IllegalStateException：配置更改后违反了设计假设。如果有人知道为什么会发生这种情况或如何解决，那就太好了。
如果覆盖getItemId()请确保也覆盖containsItem()。
我尝试了解决方案的所有方法，但没有奏效。我删除了fragmentStateAdapter中的getItemId，它现在工作正常。