RxPagedListBuilder

public final class RxPagedListBuilder
extends Object

java.lang.Object
   ↳ androidx.paging.RxPagedListBuilder<Key, Value>


Builder for Observable<PagedList> or Flowable<PagedList>, given a DataSource.Factory and a PagedList.Config.

The required parameters are in the constructor, so you can simply construct and build, or optionally enable extra features (such as initial load key, or BoundaryCallback).

The returned observable/flowable will already be subscribed on the setFetchScheduler(Scheduler), and will perform all loading on that scheduler. It will already be observed on setNotifyScheduler(Scheduler), and will dispatch new PagedLists, as well as their updates to that scheduler.

Summary

Public constructors

RxPagedListBuilder(Factory<Key, Value> dataSourceFactory, PagedList.Config config)

Creates a RxPagedListBuilder with required parameters.

RxPagedListBuilder(Factory<Key, Value> dataSourceFactory, int pageSize)

Creates a RxPagedListBuilder with required parameters.

Public methods

Flowable<PagedList<Value>> buildFlowable(BackpressureStrategy backpressureStrategy)

Constructs a Flowable<PagedList>.

Observable<PagedList<Value>> buildObservable()

Constructs a Observable<PagedList>.

RxPagedListBuilder<Key, Value> setBoundaryCallback(BoundaryCallback<Value> boundaryCallback)

Sets a PagedList.BoundaryCallback on each PagedList created, typically used to load additional data from network when paging from local storage.

RxPagedListBuilder<Key, Value> setFetchScheduler(Scheduler scheduler)

Sets scheduler which will be used for background fetching of PagedLists, as well as on-demand fetching of pages inside.

RxPagedListBuilder<Key, Value> setInitialLoadKey(Key key)

First loading key passed to the first PagedList/DataSource.

RxPagedListBuilder<Key, Value> setNotifyScheduler(Scheduler scheduler)

Sets scheduler which will be used for observing new PagedLists, as well as loading updates within the PagedLists.

Inherited methods

Public constructors

RxPagedListBuilder

public RxPagedListBuilder (Factory<Key, Value> dataSourceFactory, 
                PagedList.Config config)

Creates a RxPagedListBuilder with required parameters.

Parameters
dataSourceFactory Factory: DataSource factory providing DataSource generations.

config PagedList.Config: Paging configuration.

RxPagedListBuilder

public RxPagedListBuilder (Factory<Key, Value> dataSourceFactory, 
                int pageSize)

Creates a RxPagedListBuilder with required parameters.

This method is a convenience for:

 RxPagedListBuilder(dataSourceFactory,
         new PagedList.Config.Builder().setPageSize(pageSize).build())
 

Parameters
dataSourceFactory Factory: DataSource.Factory providing DataSource generations.

pageSize int: Size of pages to load.

Public methods

buildFlowable

public Flowable<PagedList<Value>> buildFlowable (BackpressureStrategy backpressureStrategy)

Constructs a Flowable<PagedList>. The returned Observable will already be observed on the notify scheduler, and subscribed on the fetch scheduler.

Parameters
backpressureStrategy BackpressureStrategy: BackpressureStrategy for the Flowable to use.

Returns
Flowable<PagedList<Value>> The Flowable of PagedLists

buildObservable

public Observable<PagedList<Value>> buildObservable ()

Constructs a Observable<PagedList>.

The returned Observable will already be observed on the notify scheduler, and subscribed on the fetch scheduler.

Returns
Observable<PagedList<Value>> The Observable of PagedLists

setBoundaryCallback

public RxPagedListBuilder<Key, Value> setBoundaryCallback (BoundaryCallback<Value> boundaryCallback)

Sets a PagedList.BoundaryCallback on each PagedList created, typically used to load additional data from network when paging from local storage.

Pass a BoundaryCallback to listen to when the PagedList runs out of data to load. If this method is not called, or null is passed, you will not be notified when each DataSource runs out of data to provide to its PagedList.

If you are paging from a DataSource.Factory backed by local storage, you can set a BoundaryCallback to know when there is no more information to page from local storage. This is useful to page from the network when local storage is a cache of network data.

Note that when using a BoundaryCallback with a Observable<PagedList>, method calls on the callback may be dispatched multiple times - one for each PagedList/DataSource pair. If loading network data from a BoundaryCallback, you should prevent multiple dispatches of the same method from triggering multiple simultaneous network loads.

Parameters
boundaryCallback BoundaryCallback: The boundary callback for listening to PagedList load state.

Returns
RxPagedListBuilder<Key, Value> this

setFetchScheduler

public RxPagedListBuilder<Key, Value> setFetchScheduler (Scheduler scheduler)

Sets scheduler which will be used for background fetching of PagedLists, as well as on-demand fetching of pages inside.

If not set, defaults to the Arch components I/O thread pool.

The built observable/flowable will be subscribed on this scheduler.

Parameters
scheduler Scheduler: Scheduler used to fetch from DataSources, generally a background thread pool for e.g. I/O or network loading.

Returns
RxPagedListBuilder<Key, Value> this

setInitialLoadKey

public RxPagedListBuilder<Key, Value> setInitialLoadKey (Key key)

First loading key passed to the first PagedList/DataSource.

When a new PagedList/DataSource pair is created after the first, it acquires a load key from the previous generation so that data is loaded around the position already being observed.

Parameters
key Key: Initial load key passed to the first PagedList/DataSource.

Returns
RxPagedListBuilder<Key, Value> this

setNotifyScheduler

public RxPagedListBuilder<Key, Value> setNotifyScheduler (Scheduler scheduler)

Sets scheduler which will be used for observing new PagedLists, as well as loading updates within the PagedLists.

If not set, defaults to the UI thread.

The built observable/flowable will be observed on this scheduler, so that the thread receiving PagedLists will also receive the internal updates to the PagedList.

Parameters
scheduler Scheduler: Scheduler that receives PagedList updates, and where PagedList.Callback calls are dispatched. Generally, this is the UI/main thread.

Returns
RxPagedListBuilder<Key, Value> this