在使用Android Jetpack的分页组件时,如果您的适配器没有收到回调,可能是由于以下几个原因:
检查是否正确设置了分页组件和适配器。确保您已经正确配置了PagingSource和PagingDataAdapter,并将适配器与RecyclerView绑定。
确保您的PagingSource的load方法正确实现,并返回了正确的数据。
检查您的RecyclerView是否已正确设置LayoutManager和适配器。确保LayoutManager已正确设置,并将适配器与RecyclerView绑定。
如果您使用的是Fragment作为每个页面的容器,请确保您正确实现了Fragment的生命周期方法。例如,您应该在Fragment的onCreateView方法中设置RecyclerView和适配器。
以下是一个示例代码,演示了如何使用Android Jetpack的分页组件和适配器:
PagingSource的示例代码:
class MyPagingSource(private val apiService: ApiService) : PagingSource() {
override suspend fun load(params: LoadParams): LoadResult {
try {
val page = params.key ?: 1
val response = apiService.getItems(page)
val data = response.body()?.data ?: emptyList()
val prevKey = if (page > 1) page - 1 else null
val nextKey = if (data.isNotEmpty()) page + 1 else null
return LoadResult.Page(data, prevKey, nextKey)
} catch (e: Exception) {
return LoadResult.Error(e)
}
}
}
PagingDataAdapter的示例代码:
class MyPagingAdapter : PagingDataAdapter- (diffCallback) {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val view = LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false)
return MyViewHolder(view)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val item = getItem(position)
item?.let {
holder.bind(it)
}
}
companion object {
private val diffCallback = object : DiffUtil.ItemCallback
- () {
override fun areItemsTheSame(oldItem: Item, newItem: Item): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
return oldItem == newItem
}
}
}
}
Fragment的示例代码:
class MyFragment : Fragment() {
private lateinit var binding: FragmentMyBinding
private val viewModel: MyViewModel by viewModels()
private val adapter: MyPagingAdapter by lazy { MyPagingAdapter() }
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
binding = FragmentMyBinding.inflate(inflater, container, false)
setupRecyclerView()
return binding.root
}
private fun setupRecyclerView() {
binding.recyclerView.layoutManager = LinearLayoutManager(requireContext())
binding.recyclerView.adapter = adapter
viewModel.items.observe(viewLifecycleOwner) { pagingData ->
adapter.submitData(viewLifecycleOwner.lifecycle, pagingData)
}
}
}
请根据您实际的需求和代码结构进行适当的修改和调整。同时,确保您已经在Gradle文件中引入了Paging库的依赖。