使用Paging 3+Retrofit时API请求未触发问题排查求助

我尝试使用Paging 3结合Retrofit发起API分页请求，但不知为何请求未触发。多次检查代码仍未找到问题原因——单独调用该API时可正常执行，但结合Paging 3就失效。希望有人帮忙分析原因及排查方法？

请求的完整URL为：https://picsum.photos/v2/list?page=1&limit=20

Api Service类 #

interface ApiService {
    companion object{
        const val BASE_URL = "https://picsum.photos/v2/"
    }

    @GET("list")
    suspend fun getImageList(
        @Query("page") pageNo:Int,
        @Query("limit") limit: Int=20
    ):Response<ImageListResponse>
}

Paging Source类 #

class ImagePagingSource(private val api:ApiService): PagingSource<Int, ImageItem>(){

    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, ImageItem> {
        try {
            Log.d("ImagePagingSource","Load is Called")
            val position = params.key ?: 1
            val previousKey = if (position == 1) null else position - 1
            /*
             * We don't have the total page key in this api response.
             * So restricting the call after page 10 statically.
             * */
            val nextKey = if (position == 10) null else position + 1
            val response = api.getImageList(position)
            if (!response.isSuccessful) return LoadResult.Error(Exception("Api Error : ${response.message()}"))
            if (response.body().isNullOrEmpty()) return LoadResult.Error(Exception("No Image Found"))
            Log.d("ImagePagingSource",response.body().toString())
            return LoadResult.Page(
                data = response.body()!!,
                prevKey = previousKey,
                nextKey = nextKey
            )
        } catch (e: Exception) {
            return LoadResult.Error(e)
        }
    }

    override fun getRefreshKey(state: PagingState<Int, ImageItem>): Int? {
        return state.anchorPosition?.let { anchorPosition ->
            val anchorPage = state.closestPageToPosition(anchorPosition)
            anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
        }
    }

}

Repository类 #

class HomePageRepo
@Inject
constructor(
    private val apiService: ApiService
)
{
    fun getImages() = Pager(
        config = PagingConfig(pageSize = 20, maxSize = 100),
        pagingSourceFactory = { ImagePagingSource(apiService) }
    ).liveData

    suspend fun callApi(){
        apiService.getImageList(1)
    }

}

View Model代码 #

fun getSearchResult():LiveData<PagingData<ImageItem>> = repo.getImages().cachedIn(viewModelScope)

RecyclerView分页适配器 #

class ImageShowPagingAdapter(private val context:Context) : PagingDataAdapter<
        ImageItem,
        ImageShowPagingAdapter.ImageShowViewHolder
        >(COMPARATOR) {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ImageShowViewHolder {
        val inflater = LayoutInflater.from(context)
        val view = RecViewItemImagesBinding.inflate(inflater, parent, false)
        return ImageShowViewHolder(view)
    }

    override fun onBindViewHolder(holder: ImageShowViewHolder, position: Int) {
        val item = getItem(position)
        Glide.with(context)
            .load(item?.download_url)
            .apply(
                RequestOptions()
                    .placeholder(R.drawable.all_type_content_default)
                    .error(R.drawable.all_type_content_default)
            )
            .into(holder.binding.ivImage)
    }

    inner class ImageShowViewHolder(val binding: RecViewItemImagesBinding) : RecyclerView.ViewHolder(binding.root)
    companion object {
        private val COMPARATOR = object : DiffUtil.ItemCallback<ImageItem>() {
            override fun areItemsTheSame(oldItem: ImageItem, newItem: ImageItem): Boolean {
                return oldItem.id == newItem.id
            }

            override fun areContentsTheSame(oldItem: ImageItem, newItem: ImageItem): Boolean {
                return oldItem == newItem
            }
        }
    }
}

后续补充：经排查，问题出在RecyclerView分页适配器中，目前已解决。

内容的提问来源于stack exchange，提问作者samriddha