ArrayList大小始终为0的RecycleView Kotlin

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

val recyclerView: RecyclerView = findViewById(R.id.recyclerView)
recyclerView.layoutManager = LinearLayoutManager(this)
recyclerView.adapter = MyAdapter(ArrayList())

class MyAdapter(private val dataList: ArrayList<String>) : RecyclerView.Adapter<MyAdapter.ViewHolder>() {

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

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        // 绑定数据到ViewHolder
    }

    override fun getItemCount(): Int {
        return dataList.size
    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        // ViewHolder中的控件
    }
}