android - kotlin-类不是抽象的，不实现抽象基类成员(RecyclerView)

Question

我是 Kotlin 的新手，我尝试了教程中的 RecycleView 实现，但得到了这个

class MainAdapter: RecyclerView.Adapter<CustomViewHolder>() {

    val videoTitles = listOf("First Title","Second","Third")

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

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomViewHolder {
        val layoutInflater = LayoutInflater.from(parent.context)
        val cellForRow = layoutInflater.inflate(R.layout.video_row,parent,false)
        return CustomViewHolder(cellForRow)
    }

    override fun onBindViewHolder(holder: CustomViewHolder?, position: Int) {
        val videoTitle = videoTitles.get(position)
        holder.view.textView_video_title.text = videoTitle
    }

}

class CustomViewHolder(val view: View): RecyclerView.ViewHolder(view){


}

我正在使用 Android Studio 3.4，它会导致错误吗？

Answer 1

我已经在评论里回答了。为了结束问题，我将其作为答案发布在这里。

问题:- onBindViewHolder 参数在父类中不可为 null 因此，当您覆盖它时，它应该是相同的。

class MainAdapter: RecyclerView.Adapter<MainAdapter.CustomViewHolder>() {
val videoTitles = listOf("First Title","Second","Third")
override fun getItemCount(): Int {
    return videoTitles.size
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomViewHolder {
    val layoutInflater = LayoutInflater.from(parent.context)
    val cellForRow = layoutInflater.inflate(R.layout.activity_dx,parent,false)
    return CustomViewHolder(cellForRow)
}
override fun onBindViewHolder(holder: CustomViewHolder, position: Int) {

}
inner class CustomViewHolder(val view: View): RecyclerView.ViewHolder(view){
}
}