Kotlin - RecyclerView.ViewHolder子类 - 无法访问额外的属性

Question

我已经实现了RecyclerView.ViewHolder子类，如下所示：

class PersonViewHolder(itemView: View, binding: ViewDataBinding) : RecyclerView.ViewHolder(itemView) { }

现在我试图在RecyclerView.Adapter的子类中访问它中声明的绑定属性：

override fun onBindViewHolder(holder: PersonViewHolder?, position: Int) {
        val person = persons[position]

        if (holder != null) {
            holder.binding.setVariable(BR.person, person) // line with error
            holder.binding.executePendingBindings() // line with error
        }
    }

但编译器抱怨 - Unresolved reference: binding

以下是完整的实施：

class PersonsAdapter(private var persons: Array<Person>) : RecyclerView.Adapter<PersonsAdapter.PersonViewHolder>() {
    override fun onBindViewHolder(holder: PersonViewHolder?, position: Int) {
        val person = persons[position]

        if (holder != null) {
            holder.binding.setVariable(BR.person, person)
            holder.binding.executePendingBindings()
        }
    }

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

    override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): PersonViewHolder {
        val itemView = LayoutInflater.from(parent!!.context).inflate(R.layout.list_item_person, parent, false)
        return PersonViewHolder(itemView, DataBindingUtil.bind(itemView))
    }

    class PersonViewHolder(itemView: View, binding: ViewDataBinding) : RecyclerView.ViewHolder(itemView) { }
}

如果我在这里遗失任何东西，有什么想法？请建议。

Answer 1

binding: ViewDataBinding - 您只定义构造函数参数，它永远不会保存为类的成员。使用var或val标记它以使其存储参数并在以后可以访问它。