androidx.paging

Added in 3.1.0

fun Config(
    pageSize: Int,
    prefetchDistance: Int = pageSize,
    enablePlaceholders: Boolean = true,
    initialLoadSizeHint: Int = pageSize * PagedList.Config.Builder.DEFAULT_INITIAL_PAGE_MULTIPLIER,
    maxSize: Int = PagedList.Config.MAX_SIZE_UNBOUNDED
): PagedList.Config

Constructs a PagedList.Config, convenience for PagedList.Config.Builder.

Parameters
`pageSize: Int`	Number of items loaded at once from the `DataSource`.
`prefetchDistance: Int = pageSize`	Distance the PagedList should prefetch.
`enablePlaceholders: Boolean = true`	False if null placeholders should be disabled.
`initialLoadSizeHint: Int = pageSize * PagedList.Config.Builder.DEFAULT_INITIAL_PAGE_MULTIPLIER`	Number of items to load while initializing the PagedList.
`maxSize: Int = PagedList.Config.MAX_SIZE_UNBOUNDED`	Maximum number of items to keep in memory, or `PagedList.Config.MAX_SIZE_UNBOUNDED` to disable page dropping.

PagedList

android

Added in 3.1.0

Deprecated in 3.1.0

fun <Key : Any, Value : Any> PagedList(
    dataSource: DataSource<Key, Value>,
    config: PagedList.Config,
    notifyExecutor: Executor,
    fetchExecutor: Executor,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    initialKey: Key? = null
): PagedList<Value>

Constructs a PagedList, convenience for PagedList.Builder.

Parameters
`<Key : Any>`	Type of key used to load data from the `DataSource`.
`<Value : Any>`	Type of items held and loaded by the `PagedList`.
`dataSource: DataSource<Key, Value>`	`DataSource` the `PagedList` will load from.
`config: PagedList.Config`	Config that defines how the `PagedList` loads data from its `DataSource`.
`notifyExecutor: Executor`	`Executor` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI/main thread.
`fetchExecutor: Executor`	`Executor` used to fetch from `DataSource`s, generally a background thread pool for e.g. I/O or network loading.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	`PagedList.BoundaryCallback` for listening to out-of-data events.
`initialKey: Key? = null`	`Key` the `DataSource` should load around as part of initialization.

Extension functions

awaitNotLoading

Cmn

suspend fun Flow<CombinedLoadStates>.awaitNotLoading(): CombinedLoadStates?

Function to wait on a Flow until a load has completed.

It collects on the Flow and suspends until it collects and returns the firstOrNull CombinedLoadStates where all LoadStates have settled into a non-loading state i.e. LoadState.NotLoading or LoadState.Error.

A use case could be scrolling to a position after refresh has completed:

override fun onCreate(savedInstanceState: Bundle?) {
    ...
    refreshButton.setOnClickListener {
        pagingAdapter.refresh()
        lifecycleScope.launch {
            // wait for refresh to complete
            pagingAdapter.loadStateFlow.awaitNotLoading()
            // do work after refresh
            recyclerView.scrollToPosition(position)
        }
   }
}

cachedIn

android

Added in 3.0.0

fun <T : Any> LiveData<PagingData<T>>.cachedIn(lifecycle: Lifecycle): LiveData<PagingData<T>>

Operator which caches a LiveData of PagingData within the scope of a Lifecycle.

cachedIn multicasts pages loaded and transformed by a PagingData, allowing multiple observers on the same instance of PagingData to receive the same events, avoiding redundant work, but comes at the cost of buffering those pages in memory.

Calling cachedIn is required to allow calling androidx.paging.AsyncPagingDataAdapter on the same instance of PagingData emitted by Pager or any of its transformed derivatives, as reloading data from scratch on the same generation of PagingData is an unsupported operation.

Parameters
`lifecycle: Lifecycle`	The `Lifecycle` where the page cache will be kept alive.

cachedIn

Cmn

Added in 3.0.0

fun <T : Any> Flow<PagingData<T>>.cachedIn(scope: CoroutineScope): Flow<PagingData<T>>

Caches the PagingData such that any downstream collection from this flow will share the same PagingData.

The flow is kept active as long as the given scope is active. To avoid leaks, make sure to use a scope that is already managed (like a ViewModel scope) or manually cancel it when you don't need paging anymore.

A common use case for this caching is to cache PagingData in a ViewModel. This can ensure that, upon configuration change (e.g. rotation), then new Activity will receive the existing data immediately rather than fetching it from scratch.

Note that this does not turn the Flow<PagingData> into a hot stream. It won't execute any unnecessary code unless it is being collected.

import androidx.activity.viewModels
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.ViewModel
import androidx.lifecycle.lifecycleScope
import androidx.lifecycle.viewModelScope
import androidx.paging.Pager
import androidx.paging.PagingConfig
import androidx.paging.cachedIn
import androidx.paging.map

class MyViewModel : ViewModel() {
    val flow = Pager(
        config = PagingConfig(pageSize = 40),
        pagingSourceFactory = pagingSourceFactory
    ).flow
        // Loads and transformations before the cachedIn operation will be cached, so that
        // multiple observers get the same data. This is true either for simultaneous
        // observers, or e.g. an Activity re-subscribing after being recreated
        .cachedIn(viewModelScope)
}

class MyActivity : AppCompatActivity() {
    val pagingAdapter = MyPagingAdapter()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val viewModel by viewModels<MyViewModel>()

        lifecycleScope.launch {
            viewModel.flow
                // Any transformations after the ViewModel's cachedIn step will not be cached,
                // and will instead by re-run immediately on Activity re-creation.
                .map { pagingData ->
                    // example un-cached transformation
                    pagingData.map { UiModel(it) }
                }
                .collectLatest {
                    pagingAdapter.submitData(it)
                }
        }
    }
}

Parameters
`scope: CoroutineScope`	The coroutine scope where this page cache will be kept alive.

cachedIn

android

Added in 3.0.0

fun <T : Any> LiveData<PagingData<T>>.cachedIn(scope: CoroutineScope): LiveData<PagingData<T>>

Operator which caches a LiveData of PagingData within a CoroutineScope.

Parameters
`scope: CoroutineScope`	The `CoroutineScope` where the page cache will be kept alive. Typically this would be a managed scope such as `ViewModel.viewModelScope`, which automatically cancels after the `PagingData` stream is no longer needed. Otherwise, the provided `CoroutineScope` must be manually cancelled to avoid memory leaks.

cachedIn

android

Added in 3.0.0

fun <T : Any> LiveData<PagingData<T>>.cachedIn(viewModel: ViewModel): LiveData<PagingData<T>>

Operator which caches a LiveData of PagingData within the scope of a ViewModel.

Parameters
`viewModel: ViewModel`	The `ViewModel` whose `viewModelScope` will dictate how long the page cache will be kept alive.

filter

Cmn

Added in 3.1.0

fun <T : Any> PagingData<T>.filter(predicate: suspend (T) -> Boolean): PagingData<T>

Returns a PagingData containing only elements matching the given predicate

filter

android

Added in 3.0.0

fun <T : Any> PagingData<T>.filter(executor: Executor, predicate: (T) -> Boolean): PagingData<T>

Returns a PagingData containing only elements matching the given predicate.

See also
`filter`

filterAsync

android

Added in 3.0.0

fun <T : Any> PagingData<T>.filterAsync(
    predicate: AsyncFunction<T, Boolean>,
    executor: Executor
): PagingData<T>

Returns a PagingData containing only elements matching the given predicate.

Parameters
`predicate: AsyncFunction<T, Boolean>`	`AsyncFunction` returning `false` for unmatched items which should be filtered.
`executor: Executor`	`Executor` to run the `AsyncFunction` in.

flatMap

Cmn

fun <T : Any, R : Any> PagingData<T>.flatMap(transform: suspend (T) -> Iterable<R>): PagingData<R>

Returns a PagingData of all elements returned from applying the given transform to each element, as it is loaded.

flatMap

android

fun <T : Any, R : Any> PagingData<T>.flatMap(
    executor: Executor,
    transform: (T) -> Iterable<R>
): PagingData<R>

Returns a PagingData of all elements returned from applying the given transform to each element, as it is loaded.

See also
`flatMap`

flatMapAsync

android

Added in 3.0.0

fun <T : Any, R : Any> PagingData<T>.flatMapAsync(
    transform: AsyncFunction<T, Iterable<R>>,
    executor: Executor
): PagingData<R>

Returns a PagingData of all elements returned from applying the given transform to each element, as it is loaded.

Parameters
`transform: AsyncFunction<T, Iterable<R>>`	`AsyncFunction` to transform an item of type `T` a list of items of type `R`.
`executor: Executor`	`Executor` to run the `AsyncFunction` in.

insertFooterItem

Cmn

Added in 3.0.0

fun <T : Any> PagingData<T>.insertFooterItem(
    terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE,
    item: T
): PagingData<T>

Returns a PagingData containing each original element, with the passed footer item added to the end of the list.

The footer item is added to a loaded page which marks the end of the data stream in the LoadType.APPEND direction, either by returning null in PagingSource.LoadResult.Page.nextKey. It will be removed if the last page in the list is dropped, which can happen in the case of loaded pages exceeding PagingConfig.maxSize.

Note: This operation is not idempotent, calling it multiple times will continually add more footers to the end of the list, which can be useful if multiple footer items are required.

Parameters
`terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE`	`TerminalSeparatorType` used to configure when the header and footer are added.
`item: T`	The footer to add to the end of the list once it is fully loaded in the `LoadType.APPEND` direction.

See also
`insertHeaderItem`

insertHeaderItem

Cmn

Added in 3.0.0

fun <T : Any> PagingData<T>.insertHeaderItem(
    terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE,
    item: T
): PagingData<T>

Returns a PagingData containing each original element, with the passed header item added to the start of the list.

The header item is added to a loaded page which marks the end of the data stream in the LoadType.PREPEND direction by returning null in PagingSource.LoadResult.Page.prevKey. It will be removed if the first page in the list is dropped, which can happen in the case of loaded pages exceeding PagingConfig.maxSize.

Note: This operation is not idempotent, calling it multiple times will continually add more headers to the start of the list, which can be useful if multiple header items are required.

Parameters
`terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE`	`TerminalSeparatorType` used to configure when the header and footer are added.
`item: T`	The header to add to the front of the list once it is fully loaded in the `LoadType.PREPEND` direction.

See also
`insertFooterItem`

insertSeparators

Cmn

Added in 3.1.0

fun <T : R, R : Any> PagingData<T>.insertSeparators(
    terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE,
    generator: suspend (T?, T?) -> R?
): PagingData<R>

Returns a PagingData containing each original element, with an optional separator generated by generator, given the elements before and after (or null, in boundary conditions).

Note that this transform is applied asynchronously, as pages are loaded. Potential separators between pages are only computed once both pages are loaded.

import androidx.paging.insertSeparators

/*
 * Create letter separators in an alphabetically sorted list.
 *
 * For example, if the input is:
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData.insertSeparators { before: String?, after: String? ->
        if (after != null && before?.first() != after.first()) {
            // separator - after is first item that starts with its first letter
            after.first().uppercaseChar().toString()
        } else {
            // no separator - either end of list, or first letters of before/after are the same
            null
        }
    }
}

import androidx.paging.insertSeparators
import androidx.paging.map

open class UiModel
data class ItemUiModel(val item: Item) : UiModel()
data class SeparatorUiModel(val char: Char) : UiModel()

/*
 * Create letter separators in an alphabetically sorted list of Items, with UiModel objects.
 *
 * For example, if the input is (each an `Item`):
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output a list of UiModels corresponding to:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData
        .map { item ->
            ItemUiModel(item) // convert items in stream to ItemUiModel
        }
        .insertSeparators<ItemUiModel, UiModel> { before: ItemUiModel?, after: ItemUiModel? ->
            if (after != null && before?.item?.label?.first() != after.item.label.first()) {
                // separator - after is first item that starts with its first letter
                SeparatorUiModel(after.item.label.first().uppercaseChar())
            } else {
                // no separator - either end of list, or first letters of before/after are the same
                null
            }
        }
}

Parameters
`terminalSeparatorType: TerminalSeparatorType = FULLY_COMPLETE`	`TerminalSeparatorType` used to configure when the header and footer are added.
`generator: suspend (T?, T?) -> R?`	Generator function used to construct a separator item given the item before and the item after. For terminal separators (header and footer), the arguments passed to the generator, `before` and `after`, will be `null` respectively. In cases where the fully paginated list is empty, a single separator will be added where both `before` and `after` items are `null`.

insertSeparators

android

Added in 3.0.0

fun <R : Any, T : R> PagingData<T>.insertSeparators(
    terminalSeparatorType: TerminalSeparatorType = TerminalSeparatorType.FULLY_COMPLETE,
    executor: Executor,
    generator: (T?, T?) -> R?
): PagingData<R>

Returns a PagingData containing each original element, with an optional separator generated by generator, given the elements before and after (or null, in boundary conditions).

Note that this transform is applied asynchronously, as pages are loaded. Potential separators between pages are only computed once both pages are loaded.

Kotlin callers should instead use the suspending extension function variant of insertSeparators

/*
 * Create letter separators in an alphabetically sorted list.
 *
 * For example, if the input is:
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map(pagingData ->
        // map outer stream, so we can perform transformations on each paging generation
        PagingDataTransforms.insertSeparators(pagingData, bgExecutor,
                (@Nullable String before, @Nullable String after) -> {
                    if (after != null && (before == null
                            || before.charAt(0) != after.charAt(0))) {
                        // separator - after is first item that starts with its first
                        // letter
                        return Character.toString(
                                Character.toUpperCase(after.charAt(0)));
                    } else {
                        // no separator - either end of list, or first
                        // letters of items are the same
                        return null;
                    }
                }));

/*
 * Create letter separators in an alphabetically sorted list of Items, with UiModel
 * objects.
 *
 * For example, if the input is (each an `Item`):
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output a list of UiModels corresponding to:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map(itemPagingData -> {
    // map outer stream, so we can perform transformations on each paging generation

    // first convert items in stream to UiModel.Item
    PagingData<UiModel.ItemModel> itemModelPagingData = PagingDataTransforms.map(
            itemPagingData, bgExecutor, UiModel.ItemModel::new);

    // Now insert UiModel.Separators, which makes the PagingData of generic type UiModel
    return PagingDataTransforms.insertSeparators(
            itemModelPagingData, bgExecutor,
            (@Nullable UiModel.ItemModel before, @Nullable UiModel.ItemModel after) -> {
                if (after != null && (before == null
                        || before.item.label.charAt(0) != after.item.label.charAt(0))) {
                    // separator - after is first item that starts with its first letter
                    return new UiModel.SeparatorModel(
                            Character.toUpperCase(after.item.label.charAt(0)));
                } else {
                    // no separator - either end of list, or first
                    // letters of items are the same
                    return null;
                }
            });
});

public class UiModel {
    static class ItemModel extends UiModel {
        public Item item;
        ItemModel(Item item) {
            this.item = item;
        }
    }
    static class SeparatorModel extends UiModel {
        public char character;
        SeparatorModel(char character) {
            this.character = character;
        }
    }
}

Parameters
`terminalSeparatorType: TerminalSeparatorType = TerminalSeparatorType.FULLY_COMPLETE`	`TerminalSeparatorType` used to configure when the header and footer are added.
`executor: Executor`	`Executor` to run the `generator` function in.
`generator: (T?, T?) -> R?`	Generator function used to construct a separator item given the item before and the item after. For terminal separators (header and footer), the arguments passed to the generator, `before` and `after`, will be `null` respectively. In cases where the fully paginated list is empty, a single separator will be added where both `before` and `after` items are `null`.

insertSeparatorsAsync

android

Added in 3.0.0

fun <T : R, R : Any> PagingData<T>.insertSeparatorsAsync(
    generator: AsyncFunction<AdjacentItems<T>, R?>,
    executor: Executor
): PagingData<R>

Returns a PagingData containing each original element, with an optional separator generated by generator, given the elements before and after (or null, in boundary conditions).

Note that this transform is applied asynchronously, as pages are loaded. Potential separators between pages are only computed once both pages are loaded.

import androidx.paging.AdjacentItems
import androidx.paging.insertSeparators
import androidx.paging.insertSeparatorsAsync
import androidx.paging.rxjava2.insertSeparatorsAsync

/*
 * Create letter separators in an alphabetically sorted list.
 *
 * For example, if the input is:
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData.insertSeparatorsAsync(
        AsyncFunction<AdjacentItems<String>, String?> {
            Futures.submit(
                Callable<String?> {
                    val (before, after) = it!!
                    if (after != null && before?.first() != after.first()) {
                        // separator - after is first item that starts with its first letter
                        after.first().uppercaseChar().toString()
                    } else {
                        // no separator - either end of list, or first letters of before/after are the same
                        null
                    }
                },
                executor
            )
        },
        executor
    )
}

import androidx.paging.AdjacentItems
import androidx.paging.insertSeparators
import androidx.paging.insertSeparatorsAsync
import androidx.paging.map
import androidx.paging.rxjava2.insertSeparatorsAsync

open class UiModel
data class ItemUiModel(val item: Item) : UiModel()
data class SeparatorUiModel(val char: Char) : UiModel()

/*
 * Create letter separators in an alphabetically sorted list of Items, with UiModel objects.
 *
 * For example, if the input is (each an `Item`):
 *     "apple", "apricot", "banana", "carrot"
 *
 * The operator would output a list of UiModels corresponding to:
 *     "A", "apple", "apricot", "B", "banana", "C", "carrot"
 */
pagingDataStream.map { pagingData ->
    // map outer stream, so we can perform transformations on each paging generation
    pagingData
        .map { item ->
            ItemUiModel(item) // convert items in stream to ItemUiModel
        }
        .insertSeparatorsAsync(
            AsyncFunction<AdjacentItems<ItemUiModel>, UiModel?> {
                Futures.submit(
                    Callable<UiModel> {
                        val (before, after) = it!!
                        if (after != null &&
                            before?.item?.label?.first() != after.item.label.first()
                        ) {
                            // separator - after is first item that starts with its first letter
                            SeparatorUiModel(after.item.label.first().uppercaseChar())
                        } else {
                            // no separator - either end of list, or first letters of before/after are the same
                            null
                        }
                    },
                    executor
                )
            },
            executor
        )
}

Parameters
`generator: AsyncFunction<AdjacentItems<T>, R?>`	`AsyncFunction` used to generate separator between two `AdjacentItems` or the header or footer if either `AdjacentItems.before` or `AdjacentItems.after` is `null`.
`executor: Executor`	`Executor` to run the `AsyncFunction` in.

map

Cmn

Added in 3.1.0

fun <T : Any, R : Any> PagingData<T>.map(transform: suspend (T) -> R): PagingData<R>

Returns a PagingData containing the result of applying the given transform to each element, as it is loaded.

map

android

Added in 3.0.0

fun <T : Any, R : Any> PagingData<T>.map(executor: Executor, transform: (T) -> R): PagingData<R>

Returns a PagingData containing the result of applying the given transform to each element, as it is loaded.

See also
`map`

mapAsync

android

Added in 3.0.0

fun <T : Any, R : Any> PagingData<T>.mapAsync(
    transform: AsyncFunction<T, R>,
    executor: Executor
): PagingData<R>

Returns a PagingData containing the result of applying the given transform to each element, as it is loaded.

Parameters
`transform: AsyncFunction<T, R>`	`AsyncFunction` to transform an item of type `T` to `R`.
`executor: Executor`	`Executor` to run the `AsyncFunction` in.

toFlowable

android

Added in 2.1.0

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toFlowable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this DataSource.Factory, convenience for RxPagedListBuilder.

The returned Flowable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

Parameters
`config: PagedList.Config`	Paging configuration.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `DataSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `DataSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.
`backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST`	`BackpressureStrategy` for the `Flowable` to use.

See also
`RxPagedListBuilder`
`toObservable`

toFlowable

android

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toFlowable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this PagingSource factory, convenience for RxPagedListBuilder.

Parameters
`config: PagedList.Config`	Paging configuration.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `PagingSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.
`backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST`	`BackpressureStrategy` for the `Flowable` to use.

See also
`RxPagedListBuilder`
`toObservable`

toFlowable

android

Added in 2.1.0

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toFlowable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this DataSource.Factory, convenience for RxPagedListBuilder.

Parameters
`pageSize: Int`	Page size.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `DataSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `DataSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.
`backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST`	`BackpressureStrategy` for the `Flowable` to use.

See also
`RxPagedListBuilder`
`toObservable`

toFlowable

android

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toFlowable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null,
    backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST
): Flowable<PagedList<Value>>

Constructs a Flowable<PagedList>, from this PagingSource factory, convenience for RxPagedListBuilder.

Parameters
`pageSize: Int`	Page size.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `PagingSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.
`backpressureStrategy: BackpressureStrategy = BackpressureStrategy.LATEST`	`BackpressureStrategy` for the `Flowable` to use.

See also
`RxPagedListBuilder`
`toObservable`

toLiveData

android

Added in 2.1.0

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toLiveData(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchExecutor: Executor = ArchTaskExecutor.getIOThreadExecutor()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this DataSource.Factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

Parameters
`config: PagedList.Config`	Paging configuration.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchExecutor: Executor = ArchTaskExecutor.getIOThreadExecutor()`	`Executor` for fetching data from `PagingSource`s.

See also
`LivePagedListBuilder`

toLiveData

android

Added in 2.1.0

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toLiveData(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchExecutor: Executor = ArchTaskExecutor.getIOThreadExecutor()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this DataSource.Factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

Parameters
`pageSize: Int`	Page size.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchExecutor: Executor = ArchTaskExecutor.getIOThreadExecutor()`	Executor for fetching data from DataSources.

See also
`LivePagedListBuilder`

toLiveData

android

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toLiveData(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    coroutineScope: CoroutineScope = GlobalScope,
    fetchDispatcher: CoroutineDispatcher = ArchTaskExecutor.getIOThreadExecutor()
        .asCoroutineDispatcher()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this PagingSource factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

Parameters
`config: PagedList.Config`	Paging configuration.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`coroutineScope: CoroutineScope = GlobalScope`	Set the `CoroutineScope` that page loads should be launched within. The set `coroutineScope` allows a `PagingSource` to cancel running load operations when the results are no longer needed - for example, when the containing activity is destroyed. Defaults to `GlobalScope`.
`fetchDispatcher: CoroutineDispatcher = ArchTaskExecutor.getIOThreadExecutor() .asCoroutineDispatcher()`	`CoroutineDispatcher` for fetching data from `PagingSource`s.

See also
`LivePagedListBuilder`

toLiveData

android

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toLiveData(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    coroutineScope: CoroutineScope = GlobalScope,
    fetchDispatcher: CoroutineDispatcher = ArchTaskExecutor.getIOThreadExecutor()
        .asCoroutineDispatcher()
): LiveData<PagedList<Value>>

Constructs a LiveData<PagedList>, from this PagingSource factory, convenience for LivePagedListBuilder.

No work (such as loading) is done immediately, the creation of the first PagedList is deferred until the LiveData is observed.

Parameters
`pageSize: Int`	Page size.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`coroutineScope: CoroutineScope = GlobalScope`	Set the `CoroutineScope` that page loads should be launched within. The set `coroutineScope` allows a `PagingSource` to cancel running load operations when the results are no longer needed - for example, when the containing activity is destroyed. Defaults to `GlobalScope`.
`fetchDispatcher: CoroutineDispatcher = ArchTaskExecutor.getIOThreadExecutor() .asCoroutineDispatcher()`	`CoroutineDispatcher` for fetching data from `PagingSource`s.

See also
`LivePagedListBuilder`

toObservable

android

Added in 2.1.0

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toObservable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this DataSource.Factory, convenience for RxPagedListBuilder.

The returned Observable will already be subscribed on the fetchScheduler, and will perform all loading on that scheduler. It will already be observed on notifyScheduler, and will dispatch new PagedLists, as well as their updates to that scheduler.

Parameters
`config: PagedList.Config`	Paging configuration.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `DataSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to PagedList load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `DataSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.

See also
`RxPagedListBuilder`
`toFlowable`

toObservable

android

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toObservable(
    config: PagedList.Config,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this PagingSource factory, convenience for RxPagedListBuilder.

Parameters
`config: PagedList.Config`	Paging configuration.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to PagedList load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `PagingSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.

See also
`RxPagedListBuilder`
`toFlowable`

toObservable

android

Added in 2.1.0

fun <Key : Any, Value : Any> DataSource.Factory<Key, Value>.toObservable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this DataSource.Factory, convenience for RxPagedListBuilder.

Parameters
`pageSize: Int`	Size of pages to load.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `DataSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `DataSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.

See also
`RxPagedListBuilder`
`toFlowable`

toObservable

android

fun <Key : Any, Value : Any> () -> PagingSource<Key, Value>.toObservable(
    pageSize: Int,
    initialLoadKey: Key? = null,
    boundaryCallback: PagedList.BoundaryCallback<Value>? = null,
    fetchScheduler: Scheduler? = null,
    notifyScheduler: Scheduler? = null
): Observable<PagedList<Value>>

Constructs a Observable<PagedList> from this PagingSource factory, convenience for RxPagedListBuilder.

Parameters
`pageSize: Int`	Size of pages to load.
`initialLoadKey: Key? = null`	Initial load key passed to the first `PagedList` / `PagingSource`.
`boundaryCallback: PagedList.BoundaryCallback<Value>? = null`	The boundary callback for listening to `PagedList` load state.
`fetchScheduler: Scheduler? = null`	`Scheduler` used to fetch from `PagingSource`s, generally a background thread pool for e.g. I/O or network loading.
`notifyScheduler: Scheduler? = null`	`Scheduler` that receives `PagedList` updates, and where `PagedList.Callback` calls are dispatched. Generally, this is the UI / main thread.

See also
`RxPagedListBuilder`
`toFlowable`

Extension properties

android