RecyclerView 무한 스크롤

RecyclerView addScrollListener 등록

 

abstract class EndlessRecyclerViewScrollListener(val layoutManager: LinearLayoutManager, private val startingPageIndex: Int = 0) : RecyclerView.OnScrollListener() {
    private val visibleThreshold = 5
    private var currentPage = 0
    private var previousTotalItemCount = 0
    private var loading = true

    init {
        currentPage = startingPageIndex
    }

    override fun onScrolled(view: RecyclerView, dx: Int, dy: Int) {
        val lastVisibleItemPosition = layoutManager.findLastVisibleItemPosition()
        val totalItemCount = layoutManager.itemCount
        if (totalItemCount == 0) {
            loading = true
        }
        if (loading && totalItemCount > previousTotalItemCount) {
            loading = false
            previousTotalItemCount = totalItemCount
        }
        if (!loading && lastVisibleItemPosition + visibleThreshold > totalItemCount) {
            currentPage++
            onLoadMore(currentPage, totalItemCount, view)
            loading = true
        }
    }

    fun resetState() {
        currentPage = startingPageIndex
        previousTotalItemCount = 0
        loading = true
    }

    abstract fun onLoadMore(page: Int, totalItemsCount: Int, view: RecyclerView?)
}