IssueTracker

Component used: ViewPager2

Version used: 1.0.0

Devices/Android versions reproduced on: Galaxy A7 (2018)

When I migrated from Viewpager to ViewPager2 i started receiving some strange crashes from Galaxy A7 (2018) (Sometimes on Galaxy A01).

Fatal Exception: java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionmk{db6691 position=3 id=4139523, oldPos=-1, pLpos:-1 no parent} androidx.viewpager2.widget.ViewPager2$i{c18be50 VFED..... ......I. 0,0-1080,1033 #4}, adapter:hk6$b@2659849, layout:androidx.viewpager2.widget.ViewPager2$d@b1e454e, context:com.leverx.godog.activity.MainActivity@5d470bb
       at androidx.recyclerview.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:6156)
       at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6339)
       at androidx.recyclerview.widget.GapWorker.prefetchPositionWithDeadline(GapWorker.java:288)
       at androidx.recyclerview.widget.GapWorker.flushTaskWithDeadline(GapWorker.java:345)
       at androidx.recyclerview.widget.GapWorker.flushTasksWithDeadline(GapWorker.java:361)
       at androidx.recyclerview.widget.GapWorker.prefetch(GapWorker.java:368)
       at androidx.recyclerview.widget.GapWorker.run(GapWorker.java:399)
       at android.os.Handler.handleCallback(Handler.java:883)
       at android.os.Handler.dispatchMessage(Handler.java:100)
       at android.os.Looper.loop(Looper.java:237)
       at android.app.ActivityThread.main(ActivityThread.java:7948)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1075)

Fatal Exception: java.lang.IndexOutOfBoundsException: Inconsistency detected. Invalid view holder adapter positionmk{bd46008 position=2 id=-193636676, oldPos=-1, pLpos:-1 no parent} androidx.viewpager2.widget.ViewPager2$i{c8adb0a VFED..... ........ 0,0-1080,1033 #18}, adapter:hk6$b@9987f7b, layout:androidx.viewpager2.widget.ViewPager2$d@e7f198, context:com.leverx.godog.activity.MainActivity@f3640c1
       at androidx.recyclerview.widget.RecyclerView$Recycler.validateViewHolderForOffsetPosition(RecyclerView.java:6156)
       at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6339)
       at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6300)
       at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6296)
       at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2330)
       at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1631)
       at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1591)
       at androidx.recyclerview.widget.LinearLayoutManager.scrollBy(LinearLayoutManager.java:1395)
       at androidx.recyclerview.widget.LinearLayoutManager.scrollHorizontallyBy(LinearLayoutManager.java:1124)
       at androidx.recyclerview.widget.RecyclerView.scrollStep(RecyclerView.java:1969)
       at androidx.recyclerview.widget.RecyclerView$SmoothScroller.onAnimation(RecyclerView.java:12316)
       at androidx.recyclerview.widget.RecyclerView$ViewFlinger.run(RecyclerView.java:5564)
       at android.view.Choreographer$CallbackRecord.run(Choreographer.java:996)
       at android.view.Choreographer.doCallbacks(Choreographer.java:794)
       at android.view.Choreographer.doFrame(Choreographer.java:725)
       at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:981)
       at android.os.Handler.handleCallback(Handler.java:883)
       at android.os.Handler.dispatchMessage(Handler.java:100)
       at android.os.Looper.loop(Looper.java:237)
       at android.app.ActivityThread.main(ActivityThread.java:7948)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1075)

I also use custom adapter for ViewPager2 like this

abstract class ViewPager2AdapterWithFragmentsReference<KEY>(private val fragmentManager: FragmentManager, lifecycle: Lifecycle) : FragmentStateAdapter(fragmentManager, lifecycle) {
    abstract fun getKey(position: Int): KEY

    fun findByKey(key: KEY): Fragment? {
        //If ViewPage2 implementation is changed, it will be affected
        return fragmentManager.findFragmentByTag("f${key.id}")
    }

    final override fun getItemId(position: Int): Long {
        return getKey(position).id
    }

    final override fun containsItem(itemId: Long): Boolean {
        repeat(itemCount) {
            if (getKey(it).id == itemId) {
                return true
            }
        }

        return false
    }

    private val KEY.id: Long
        get() = hashCodeLong()
}