RecyclerView in RecyclerView with FlexboxLayoutManager only show one line

I use a recyclerview(just call it the ARecyclerView with LinearLayoutManager ) and make another recyclerview(just call it the BRecyclerView with FlexboxLayoutManager) as the item of ARecyclerView**.

But after I call notifyDataSetChanged() ,the BRecyclerView only show one line whenever the data change. What I want is it should show more than one line because the BRecyclerView don’t show all data. The BRecyclerView layout is

<android.support.v7.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/training_term_and_lesson_item_list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:listitem="@layout/training_item_venue_filter" />

and the item of BRecyclerView is

<?xml version="1.0" encoding="utf-8"?>
<CheckBox xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/training_item_venue_filter_venue_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginEnd="20dp"
    android:layout_marginRight="20dp"
    android:layout_marginTop="15dp"
    android:background="@drawable/commonsdk_bg_checkbox_corner_5"
    android:button="@null"
    android:gravity="center"
    android:minWidth="80dp"
    android:paddingBottom="7dp"
    android:paddingEnd="13dp"
    android:paddingLeft="13dp"
    android:paddingRight="13dp"
    android:paddingStart="13dp"
    android:paddingTop="7dp"
    android:textColor="@drawable/commonsdk_checkbox_text_color_normal_white"
    android:textSize="@dimen/commonsdk_super_small_text"
    tools:text="Hello World" />

Expected behavior

What I want it show is

Version of the flexbox library

0.3.0-alpha3*

[IDevelopes]

Its 2020 and this issue is still present 😕

[Ratul-Bin-Tazul]

The issue is still present. Using layoutManager.setFlexDirection(FlexDirection.ROW); layoutManager.setFlexWrap(FlexWrap.WRAP);