class ExamplePagingSource(
val backend: ExampleBackendService,
val query: String
) : PagingSource<Int, User>() {
override suspend fun load(
params: LoadParams<Int>
): LoadResult<Int, User> {
try {
// Start refresh at page 1 if undefined.
val nextPageNumber = params.key ?: 1
val response = backend.searchUsers(query, nextPageNumber)
return LoadResult.Page(
data = response.users,
prevKey = null, // Only paging forward.
nextKey = response.nextPageNumber
)
} catch (e: Exception) {
// Handle errors in this block and return LoadResult.Error if it is an
// expected error (such as a network failure).
}
}
override fun getRefreshKey(state: PagingState<Int, User>): Int? {
// Try to find the page key of the closest page to anchorPosition, from
// either the prevKey or the nextKey, but you need to handle nullability
// here:
// * prevKey == null -> anchorPage is the first page.
// * nextKey == null -> anchorPage is the last page.
// * both prevKey and nextKey null -> anchorPage is the initial page, so
// just return null.
return state.anchorPosition?.let { anchorPosition ->
val anchorPage = state.closestPageToPosition(anchorPosition)
anchorPage?.prevKey?.plus(1) ?: anchorPage?.nextKey?.minus(1)
}
}
}
我试图在选择新国家/地区时删除突出显示的国家/地区,但无法读取属性或 countryBorders.remove() 不是函数 下面是在选择新国家/地区时设置样式和删除所选国家/地区的代码
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