섹션5 리사이클러 뷰(recycler view) 만들어보기

섹션5 리사이클러 뷰(recycler view) 만들어보기 수강 중 강사님의 결과와 달라서 질문드립니다.

해당 강의 11:58까지 따라하면 강사님의 결과는

이렇게 a, b, c가 출력되던데

저는 이렇게 a만 출력됩니다.(10:14에서도 강사님의 화면에는 rv가 3개 나오던데 저는 마찬가지로 1개만 나와요.)

제가 뭘 잘못했는지 궁금합니다 ㅠㅠ

소스코드(Main.activity)

package com.example.rv_ex

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val items = mutableListOf<String>()

        items.add("a")
        items.add("b")
        items.add("c")

        val rv = findViewById<RecyclerView>(R.id.rv)

        val rvAdapter = RVAdapter(items)

        rv.adapter = rvAdapter
        rv.layoutManager = LinearLayoutManager(this)
    }
}

소스코드(RVAdapter)

package com.example.rv_ex

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView

class RVAdapter(val items: MutableList<String>) : RecyclerView.Adapter<RVAdapter.ViewHolder>(){

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RVAdapter.ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.rv_item, parent, false)

        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: RVAdapter.ViewHolder, position: Int) {
        holder.bindItems(items[position])
    }

    //전체 리사이클러뷰의 개수
    override fun getItemCount(): Int {
        return items.size
    }

    inner class ViewHolder(itemView: View): RecyclerView.ViewHolder(itemView) {

        fun bindItems(item: String) {
            val rv_text = itemView.findViewById<TextView>(R.id.rvItem)
            rv_text.text = item
        }
    }

}

소스코드(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">

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

</androidx.constraintlayout.widget.ConstraintLayout>

소스코드(rv_item.xml)

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

    <TextView
        android:id="@+id/rvItem"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:text="rv"
        android:textSize="20sp" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="100dp">

    <TextView
        android:id="@+id/rvItem"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:text="rv"
        android:textSize="20sp" />
</LinearLayout>