FlexboxLayoutManager item flickering on scrolling of another Recycler View - android-recyclerview

Question

I have 2 recyclerView, RecyclerView 1, having layoutManager with app:layoutManager="com.google.android.flexbox.FlexboxLayoutManager" & another RecyclerView 2, having app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager".
The first recyclerview item is flickering when scrolling on another recyclerView. It's working fine when item count of RecyclerView 1 is less than 6 or 7.
Please check the video link for the issue reference(0:18s - 0:46s): https://drive.google.com/file/d/17_wa3vd5H7QKh0fgj6Sh310ZNlt2TeG1/view?usp=sharing
Please find the code-snippet below:
activity_personal_activities.xml
<ScrollView
android:id="#+id/scrollView"
android:layout_width="match_parent"
android:layout_height="#dimen/dp_0"
android:fillViewport="true"
app:layout_constraintBottom_toTopOf="#+id/btnSave"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/tvHeaderTitle">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvConditionsSelected"
android:layout_width="#dimen/dp_0"
android:layout_height="wrap_content"
android:layout_marginTop="#dimen/dp_12"
android:layout_marginBottom="#dimen/dp_20"
android:orientation="horizontal"
android:paddingStart="#dimen/dp_24"
android:paddingEnd="#dimen/dp_0"
app:layoutManager="com.google.android.flexbox.FlexboxLayoutManager"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_max="#dimen/dp_100"
app:layout_constraintHorizontal_bias="0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:spanCount="2"
tools:itemCount="4"
tools:listitem="#layout/inflate_conditions_selected" />
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvConditions"
android:layout_width="match_parent"
android:layout_height="#dimen/dp_0"
android:layout_marginTop="#dimen/dp_7"
android:orientation="vertical"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#id/rvConditionsSelected"
tools:itemCount="5"
tools:listitem="#layout/inflate_conditions" />
</androidx.constraintlayout.widget.ConstraintLayout>
</ScrollView>
Setting up adapter:
(bViewDataBinding?.rvConditionsSelected?.itemAnimator as? DefaultItemAnimator)?.supportsChangeAnimations = false
bViewDataBinding?.rvConditionsSelected?.adapter = adapter
ScrollToPosition of RecyclerView 1, On Adding new Item
bViewDataBinding?.rvConditionsSelected?.scrollToPosition(adapterList.size - 1)

Answer 1

I found the root cause of the flicker issue & the Problem was with the first recyclerView height. So I fixed this issue by adding a fixed height initially. If you see in my query, recyclerView height is android:layout_height="#dimen/dp_0" & app:layout_constraintHeight_max="#dimen/dp_100" that is causing the flicker on the FlaxBoxLayoutManager recyclerView.
<androidx.recyclerview.widget.RecyclerView
android:id="#+id/rvConditionsSelected"
android:layout_width="match_parent"
android:layout_height="#dimen/dp_36"
android:layout_marginTop="#dimen/dp_12"
android:orientation="horizontal"
app:layoutManager="com.google.android.flexbox.FlexboxLayoutManager"
android:paddingStart="#dimen/dp_24"
android:paddingEnd="#dimen/dp_0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#id/cvSearch"
tools:itemCount="4"
tools:listitem="#layout/inflate_conditions_selected" />
So, I'm changing the height of recyclerView programmatically
override fun updateRecyclerViewHeight() {
val flexSize = (bViewDataBinding?.rvConditionsSelected?.layoutManager as? FlexboxLayoutManager)?.flexLinesInternal?.size
?: return
when (flexSize) {
3 -> changeRecyclerViewHeight(SizeUtils.dp2px(this,100F))
2 -> changeRecyclerViewHeight(SizeUtils.dp2px(this,72F))
1 -> changeRecyclerViewHeight(SizeUtils.dp2px(this,36F))
}
}
override fun changeRecyclerViewHeight(height: Int) {
val params = bViewDataBinding?.rvConditionsSelected?.layoutParams
params?.height = height
bViewDataBinding?.rvConditionsSelected?.layoutParams = params
}