Page

COUNT_UNDEFINED

const val COUNT_UNDEFINED: Int

Value: Int.MIN_VALUE

<init>

Page(
    data: List<Value>, 
    prevKey: Key?, 
    nextKey: Key?)

Success result object for PagingSource.load.

<init>

Page(
    data: List<Value>, 
    prevKey: Key?, 
    nextKey: Key?, 
    @IntRange(-2147483648) itemsBefore: Int = COUNT_UNDEFINED, 
    @IntRange(-2147483648) itemsAfter: Int = COUNT_UNDEFINED)

Success result object for PagingSource.load.

// One common method of pagination is to use next (and optionally previous) tokens.
// The below code shows you how to
data class NetworkResponseObject(
    val items: List<Item>,
    val next: String,
    val approximateItemsRemaining: Int
)

// The following shows how you use convert such a response loaded in PagingSource.load() to
// a Page, which can be returned from that method
fun NetworkResponseObject.toPage() = LoadResult.Page(
    data = items,
    prevKey = null, // this implementation can only append, can't load a prepend
    nextKey = next, // next token will be the params.key of a subsequent append load
    itemsAfter = approximateItemsRemaining
)

// If you load by page number, the response may not define how to load the next page.
data class NetworkResponseObject(
    val items: List<Item>
)

// The following shows how you use the current page number (e.g., the current key in
// PagingSource.load() to convert a response into a Page, which can be returned from that method
fun NetworkResponseObject.toPage(pageNumber: Int): LoadResult.Page<Int, Item> {
    return LoadResult.Page(
        data = items,
        // Since 0 is the lowest page number, return null to signify no more pages
        // should be loaded before it.
        prevKey = if (pageNumber > 0) pageNumber - 1 else null,
        // This API defines that it's out of data when a page returns empty. When out of
        // data, we return `null` to signify no more pages should be loaded
        // If the response instead
        nextKey = if (items.isNotEmpty()) pageNumber + 1 else null
    )
}

data

val data: List<Value>

Loaded data

itemsAfter

val itemsAfter: Int

Optional count of items after the loaded data.

itemsBefore

val itemsBefore: Int

Optional count of items before the loaded data.

nextKey

val nextKey: Key?

Key for next page if more data can be loaded in that direction, null otherwise.

prevKey

val prevKey: Key?

Key for previous page if more data can be loaded in that direction, null otherwise.