Custom PagedListAdapter with add support on top

CommentAdapter.kt

/**
 * Created by guness on 7.02.2018.
 */
class CommentAdapter(private val fragment: SGFragment) : RecyclerView.Adapter<CommentViewHolder>() {

    private val mCustomList = ArrayList<Comment>()

    private val mListener = object : ListUpdateCallback {
        override fun onChanged(position: Int, count: Int, payload: Any?) {
            notifyItemRangeChanged(paged(position), count, payload)
        }

        override fun onMoved(fromPosition: Int, toPosition: Int) {
            notifyItemMoved(paged(fromPosition), paged(toPosition))
        }

        override fun onInserted(position: Int, count: Int) {
            notifyItemRangeInserted(paged(position), count)
        }

        override fun onRemoved(position: Int, count: Int) {
            notifyItemRangeRemoved(paged(position), count)
        }
    }

    private val mHelper = PagedListAdapterHelper(mListener, ListAdapterConfig.Builder<Comment>().setDiffCallback(diffCallback).build())

    private fun paged(position: Int) = position - mCustomList.size

    override fun getItemCount(): Int {
        return mHelper.itemCount + mCustomList.size
    }

    private fun getItem(position: Int): Comment? {
        return if (mCustomList.size > position) {
            mCustomList[position]
        } else {
            mHelper.currentList?.get(paged(position))
        }
    }

    fun setList(list: PagedList<Comment>?) {
        mCustomList.clear()
        mHelper.setList(list)
    }

    fun addComment(comment: Comment) {
        mCustomList.add(0, comment)
        notifyItemInserted(0)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CommentViewHolder {
        val itemView = LayoutInflater.from(parent.context).inflate(R.layout.item_comment, parent, false)
        return CommentViewHolder(itemView, fragment)
    }

    override fun onBindViewHolder(holder: CommentViewHolder, position: Int) {
        holder.bind(getItem(position))
    }

    companion object {
        private val diffCallback = object : DiffCallback<Comment>() {
            override fun areItemsTheSame(oldItem: Comment, newItem: Comment): Boolean = oldItem.id == newItem.id

            override fun areContentsTheSame(oldItem: Comment, newItem: Comment): Boolean {
                return oldItem.id == newItem.id &&
                        oldItem.content == newItem.content &&
                        oldItem.user?.id == newItem.user?.id &&
                        oldItem.user?.name == newItem.user?.name &&
                        oldItem.user?.avatar == newItem.user?.avatar
            }
        }
    }
}

Can you share PagedListAdapterHelper

Can you share PagedListAdapterHelper

Can you share PagedListAdapterHelper

+1

cc @guness

Can you share PagedListAdapterHelper

I think it is this one, however looks like it does not exist on recent versions:

https://github.com/Rayduh/support/blob/master/paging/runtime/src/main/java/android/arch/util/paging/PagedListAdapterHelper.java