Jetpack Compose Paging3调用追加以加载下一页

import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.runtime.Composable
import androidx.paging.Pager
import androidx.paging.PagingConfig
import androidx.paging.PagingData
import androidx.paging.compose.LazyPagingItems
import androidx.paging.compose.collectAsLazyPagingItems

@Composable
fun PagingExample() {
    val pager = Pager(
        config = PagingConfig(pageSize = 20),
        pagingSourceFactory = { MyPagingSource() }
    )

    val pagingItems: LazyPagingItems<MyData> = pager.flow.collectAsLazyPagingItems()

    LazyColumn {
        items(pagingItems) { item ->
            // 绑定数据到 UI 组件
            DataItem(item)
        }
    }
}

class MyPagingSource : PagingSource<Int, MyData>() {
    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, MyData> {
        return try {
            val page = params.key ?: 1
            val response = fetchData(page) // 从数据源获取数据
            LoadResult.Page(
                data = response,
                prevKey = if (page == 1) null else page - 1,
                nextKey = if (response.isEmpty()) null else page + 1
            )
        } catch (e: Exception) {
            LoadResult.Error(e)
        }
    }

    private suspend fun fetchData(page: Int): List<MyData> {
        // 模拟从数据源获取数据
        return listOf(/* 数据项 */)
    }
}

data class MyData(val id: Int, val name: String)

@Composable
fun DataItem(data: MyData) {
    // 绑定数据到 UI 组件
}