{% setvar book_path %}/reference/kotlin/androidx/_book.yaml{% endsetvar %} {% include "_shared/_reference-head-tags.html" %}
abstract class RxPagingSource<Key : Any, Value : Any> : PagingSource
Rx-based compatibility wrapper around PagingSource
's suspending APIs.
/** * Sample RxPagingSource which loads `Item`s from network requests via Retrofit to a backend * service, which uses String tokens to load pages (each response has a next/previous token). */ class MyPagingSource( val myBackend: RxBackendService, val searchTerm: String ) : RxPagingSource<String, Item>() { override fun loadSingle(params: LoadParams<String>): Single<LoadResult<String, Item>> { return myBackend // Single-based network load .searchUsers(searchTerm, params.key) .subscribeOn(Schedulers.io()) .map<LoadResult<String, Item>> { result -> LoadResult.Page( data = result.items, prevKey = result.prev, nextKey = result.next ) } .onErrorReturn { e -> when (e) { // Retrofit calls that return the body type throw either IOException for // network failures, or HttpException for any non-2xx HTTP status codes. // This code reports all errors to the UI, but you can inspect/wrap the // exceptions to provide more context. is IOException -> LoadResult.Error(e) is HttpException -> LoadResult.Error(e) else -> throw e } } } override fun getRefreshKey(state: PagingState<String, Item>): String? { return state.anchorPosition?.let { state.closestItemToPosition(it)?.id } } }
Public properties |
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Boolean |
Whether this |
open Boolean |
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open Boolean |
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Public constructors |
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<Key : Any, Value : Any> RxPagingSource() |
Public functions |
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final suspend PagingSource.LoadResult<Key, Value> |
load(params: PagingSource.LoadParams<Key>) Loading API for |
abstract <ERROR CLASS><PagingSource.LoadResult<Key, Value>> |
loadSingle(params: PagingSource.LoadParams<Key>) Loading API for |
Inherited functions |
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val invalid: Boolean
Whether this PagingSource
has been invalidated, which should happen when the data this PagingSource
represents changes since it was first instantiated.
open val jumpingSupported: Boolean
true
if this PagingSource
supports jumping, false
otherwise.
Override this to true
if pseudo-fast scrolling via jumps is supported.
A jump occurs when a RecyclerView
scrolls through a number of placeholders defined by PagingConfig.jumpThreshold
and triggers a load with LoadType
.
PagingSource
s that support jumps should override getRefreshKey
to return a Key
that would load data fulfilling the viewport given a user's current PagingState.anchorPosition
.
See also | |
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jumpThreshold |
open val keyReuseSupported: Boolean
true
if this PagingSource
expects to re-use keys to load distinct pages without a call to invalidate
, false
otherwise.
final suspend fun load(params: PagingSource.LoadParams<Key>): PagingSource.LoadResult<Key, Value>
Loading API for PagingSource
.
Implement this method to trigger your async load (e.g. from database or network).
abstract fun loadSingle(params: PagingSource.LoadParams<Key>): <ERROR CLASS><PagingSource.LoadResult<Key, Value>>
Loading API for PagingSource
.
Implement this method to trigger your async load (e.g. from database or network).