{% setvar book_path %}/reference/androidx/_book.yaml{% endsetvar %} {% include "_shared/_reference-head-tags.html" %}
public abstract class RxPagingSource<Key extends Object, Value extends Object> extends 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 fields |
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final boolean |
Whether this |
boolean |
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boolean |
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Public constructors |
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<Key extends Object, Value extends Object> RxPagingSource() |
Public methods |
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final @NonNull PagingSource.LoadResult<@NonNull Key, @NonNull Value> |
load(@NonNull PagingSource.LoadParams<@NonNull Key> params) Loading API for |
abstract @NonNull <ERROR CLASS><@NonNull PagingSource.LoadResult<@NonNull Key, @NonNull Value>> |
loadSingle(@NonNull PagingSource.LoadParams<@NonNull Key> params) Loading API for |
Inherited methods |
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@NonNull
public final boolean invalid
Whether this PagingSource
has been invalidated, which should happen when the data this PagingSource
represents changes since it was first instantiated.
@NonNull
public boolean jumpingSupported
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
.
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jumpThreshold |
@NonNull
public boolean keyReuseSupported
true
if this PagingSource
expects to re-use keys to load distinct pages without a call to invalidate
, false
otherwise.
@NonNull
public final PagingSource.LoadResult<@NonNull Key, @NonNull Value> load(@NonNull PagingSource.LoadParams<@NonNull Key> params)
Loading API for PagingSource
.
Implement this method to trigger your async load (e.g. from database or network).
@NonNull
public abstract <ERROR CLASS><@NonNull PagingSource.LoadResult<@NonNull Key, @NonNull Value>> loadSingle(@NonNull PagingSource.LoadParams<@NonNull Key> params)
Loading API for PagingSource
.
Implement this method to trigger your async load (e.g. from database or network).