Android RecyclerView使用ListAdapter高效刷新数据的操作方法

class DiffCallBack(val oldList: ArrayList<Person>, val newList: ArrayList<Person>) :DiffUtil.Callback() {

    //判断两个对象是否相同
    override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
        
        return oldList[oldItemPosition].id == newList[newItemPosition].id
    }

    override fun getOldListSize(): Int {
        return oldList.size
    }

    override fun getNewListSize(): Int {
        return newList.size
    }

    //判断两个对象内容是否相同
    override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
        val newItem = newList[newItemPosition]
        val oldItem = oldList[oldItemPosition]

        //如果新数据和旧数据的名称和年龄相同,则视为两个item的内容相同
        return oldItem.age == newItem.age && oldItem.name == newItem.name
    }

}

val oldList = adapter.getData()
//深拷贝oldList得到newList,然后对newList按照业务进行增删改的操作,这里代码就省略了..

//计算不同之处
val diffResult = DiffUtil.calculateDiff(DiffCallBack(oldList,newList))
//adapter设置新数据
adapter.setData(newList)
//将变更操作分发给adapter
diffResult.dispatchUpdatesTo(adapter)

class RvAdapter() : ListAdapter<Person, RvAdapter.ViewHolder>(diffCallback) {

    compaNIOn object {
        val diffCallback = object : DiffUtil.ItemCallback<Person>() {
            override fun areItemsTheSame(oldItem: Person, newItem: Person): Boolean {
                return oldItem.id == newItem.id
            }

            override fun areContentsTheSame(oldItem: Person, newItem: Person): Boolean {
                //如果新数据和旧数据的名称和年龄相同,则视为两个item的内容相同
                return oldItem.age == newItem.age && oldItem.name == newItem.name
            }

        }
    }

    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var tvAge: TextView = itemView.findViewById(R.id.tvAge)
        var tvName: TextView = itemView.findViewById(R.id.tvUserName)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val itemView = View.inflate(parent.context, R.layout.rv_item_person, null)
        return ViewHolder(itemView)
    }


    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = getItem(position)
        holder.tvName.text = item.name
        holder.tvAge.text = item.age.toString()
    }
}

val oldList = adapter.currentList

val newList = oldList.map { it }.toMutableList()
newList.removeAt(10)
//下标2加个新数据
newList.add(2, Person(90, "我的", 72))
adapter.submitList(list)