Kotlin - RecyclerView doesn't display items but no error

I try to make a simple recycler view on Kotlin with Android Studio. But it doesn't display item. \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

I have a MainActivity.kt :

package fr.monarch.viper

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import fr.monarch.viper.fragments.CommandesFragment

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //injecter le fragment commandes fragment
        val transaction = supportFragmentManager.beginTransaction()
        transaction.replace(R.id.fragment_container, CommandesFragment())
        transaction.addToBackStack(null)
        transaction.commit()
    }
}

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A activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        style="@style/DefaultTextStyle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="@dimen/default_margin"
        android:layout_marginTop="@dimen/default_margin"
        android:text="@string/app_name"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <FrameLayout
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginTop="60dp"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

fragment_page.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:text="@string/commandes_effectuees"
        android:layout_marginTop="@dimen/default_margin"
        android:layout_marginStart="@dimen/default_margin"/>

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/commandes_recycler"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        />

</LinearLayout>

Fragment class.kt

package fr.monarch.viper.fragments

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.RecyclerView
import fr.monarch.viper.R
import fr.monarch.viper.adapter.ItemAdapter

class CommandesFragment : Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        val view = inflater.inflate(R.layout.fragment_commandes, container,false)

        val verticalRecycler = view.findViewById<RecyclerView>(R.id.commandes_recycler)
        verticalRecycler.adapter = ItemAdapter(R.layout.item_commande)

        return view
    }
}

ItemAdapter class .kt

package fr.monarch.viper.adapter

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import fr.monarch.viper.R

class ItemAdapter(private val layoutId : Int) : RecyclerView.Adapter<ItemAdapter.ViewHolder>(){

    //Pour ranger tous les items
    class ViewHolder(view: View): RecyclerView.ViewHolder(view){
        //image item
        var article_image = view.findViewById<ImageView>(R.id.article_image)
        var article_name = view.findViewById<TextView>(R.id.article_name)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater
            .from(parent.context)
            .inflate(layoutId, parent,false)
        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    }

    override fun getItemCount(): Int = 5
    }

and my item layout

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <androidx.cardview.widget.CardView
        android:id="@+id/cardView"
        android:layout_width="80dp"
        android:layout_height="80dp"
        app:cardCornerRadius="10dp"
        app:cardElevation="6dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <ImageView
            android:id="@+id/article_image"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="centerCrop"
            android:src="@drawable/item_photo"
            />

    </androidx.cardview.widget.CardView>

    <View
        android:id="@+id/view_separation"
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:visibility="invisible"
        android:background="@color/black"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/article_name"
        style="@style/DefaultTextStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/commande_item_name"
        app:layout_constraintBottom_toTopOf="@+id/view_separation"
        app:layout_constraintStart_toEndOf="@+id/cardView"
        android:layout_marginStart="10dp"/>

    <TextView
        android:id="@+id/article_price"
        style="@style/SousTitreStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/commande_item_price"
        app:layout_constraintStart_toStartOf="@+id/article_name"
        app:layout_constraintTop_toBottomOf="@+id/view_separation" />


</androidx.constraintlayout.widget.ConstraintLayout>

The problem is that it display no item in the recycler view and I get no error.