{% setvar book_path %}/reference/kotlin/androidx/_book.yaml{% endsetvar %} {% include "_shared/_reference-head-tags.html" %}
class PagedList.Builder<Key : Any, Value : Any>
Builder class for PagedList
.
pagingSource
, config
, notifyDispatcher
and fetchDispatcher
must all be provided.
A PagedList
queries initial data from its PagingSource
during construction, to avoid empty PagedList
s being presented to the UI when possible. It's preferred to present initial data, so that the UI doesn't show an empty list, or placeholders for a few frames, just before showing initial content.
LivePagedListBuilder
does this creation on a background thread automatically, if you want to receive a LiveData<PagedList<...>>
.
Parameters | |
---|---|
<Key : Any> |
Type of key used to load data from the |
<Value : Any> |
Type of items held and loaded by the |
Public constructors |
|
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<Key : Any, Value : Any> Builder( Create a |
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<Key : Any, Value : Any> Builder( Create a |
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<Key : Any, Value : Any> Builder( Create a |
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<Key : Any, Value : Any> Builder( Create a |
Public functions |
|
---|---|
PagedList<Value> |
build() Creates a |
PagedList.Builder<Key, Value> |
setBoundaryCallback( The |
PagedList.Builder<Key, Value> |
setCoroutineScope(coroutineScope: CoroutineScope) Set the |
PagedList.Builder<Key, Value> |
setFetchDispatcher(fetchDispatcher: CoroutineDispatcher) The |
PagedList.Builder<Key, Value> |
This function is deprecated. Passing an executor will cause it get wrapped as a CoroutineDispatcher, consider passing a CoroutineDispatcher directly |
PagedList.Builder<Key, Value> |
setInitialKey(initialKey: Key?) Sets the initial key the |
PagedList.Builder<Key, Value> |
setNotifyDispatcher(notifyDispatcher: CoroutineDispatcher) The |
PagedList.Builder<Key, Value> |
This function is deprecated. Passing an executor will cause it get wrapped as a CoroutineDispatcher, consider passing a CoroutineDispatcher directly |
<Key : Any, Value : Any> Builder(
dataSource: DataSource<Key, Value>,
config: PagedList.Config
)
Create a Builder
with the provided DataSource
and Config
.
Parameters | |
---|---|
dataSource: DataSource<Key, Value> |
|
config: PagedList.Config |
|
<Key : Any, Value : Any> Builder(
dataSource: DataSource<Key, Value>,
pageSize: Int
)
Create a PagedList.Builder
with the provided DataSource
and pageSize
.
This method is a convenience for:
PagedList.Builder(dataSource,
new PagedList.Config.Builder().setPageSize(pageSize).build());
Parameters | |
---|---|
dataSource: DataSource<Key, Value> |
|
pageSize: Int |
Size of loaded pages when the |
<Key : Any, Value : Any> Builder(
pagingSource: PagingSource<Key, Value>,
initialPage: PagingSource.LoadResult.Page<Key, Value>,
config: PagedList.Config
)
Create a PagedList.Builder
with the provided PagingSource
, initial PagingSource.LoadResult.Page
, and PagedList.Config
.
Parameters | |
---|---|
pagingSource: PagingSource<Key, Value> |
|
initialPage: PagingSource.LoadResult.Page<Key, Value> |
Initial page loaded from the |
config: PagedList.Config |
|
<Key : Any, Value : Any> Builder(
pagingSource: PagingSource<Key, Value>,
initialPage: PagingSource.LoadResult.Page<Key, Value>,
pageSize: Int
)
Create a PagedList.Builder
with the provided PagingSource
, initial PagingSource.LoadResult.Page
, and pageSize
.
This method is a convenience for:
PagedList.Builder(
pagingSource,
page,
PagedList.Config.Builder().setPageSize(pageSize).build()
)
Parameters | |
---|---|
pagingSource: PagingSource<Key, Value> |
|
initialPage: PagingSource.LoadResult.Page<Key, Value> |
Initial page loaded from the |
pageSize: Int |
Size of loaded pages when the |
fun build(): PagedList<Value>
Creates a PagedList
with the given parameters.
This call will dispatch the androidx.paging.PagingSource
's loadInitial method immediately on the current thread, and block the current on the result. This method should always be called on a worker thread to prevent blocking the main thread.
It's fine to create a PagedList
with an async PagingSource
on the main thread, such as in the constructor of a ViewModel. An async network load won't block the initial call to the Load function. For a synchronous PagingSource
such as one created from a Room database, a LiveData<PagedList>
can be safely constructed with androidx.paging.LivePagedListBuilder
on the main thread, since actual construction work is deferred, and done on a background thread.
While build
will always return a PagedList
, it's important to note that the PagedList
initial load may fail to acquire data from the PagingSource
. This can happen for example if the PagingSource
is invalidated during its initial load. If this happens, the PagedList
will be immediately detached
, and you can retry construction (including setting a new PagingSource
).
Throws | |
---|---|
kotlin.IllegalArgumentException |
if |
fun setBoundaryCallback(
boundaryCallback: PagedList.BoundaryCallback<Value>?
): PagedList.Builder<Key, Value>
The BoundaryCallback
for out of data events.
Pass a BoundaryCallback
to listen to when the PagedList
runs out of data to load.
Parameters | |
---|---|
boundaryCallback: PagedList.BoundaryCallback<Value>? |
|
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |
fun setCoroutineScope(coroutineScope: CoroutineScope): PagedList.Builder<Key, Value>
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
.
Parameters | |
---|---|
coroutineScope: CoroutineScope |
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |
fun setFetchDispatcher(fetchDispatcher: CoroutineDispatcher): PagedList.Builder<Key, Value>
The CoroutineDispatcher
used to fetch additional pages from the PagingSource
.
Does not affect initial load, which will be done immediately on whichever thread the PagedList
is created on.
Parameters | |
---|---|
fetchDispatcher: CoroutineDispatcher |
|
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |
funsetFetchExecutor(fetchExecutor: Executor): PagedList.Builder<Key, Value>
The Executor
used to fetch additional pages from the PagingSource
.
Does not affect initial load, which will be done immediately on whichever thread the PagedList
is created on.
Parameters | |
---|---|
fetchExecutor: Executor |
|
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |
fun setInitialKey(initialKey: Key?): PagedList.Builder<Key, Value>
Sets the initial key the PagingSource
should load around as part of initialization.
Parameters | |
---|---|
initialKey: Key? |
Key the |
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |
fun setNotifyDispatcher(notifyDispatcher: CoroutineDispatcher): PagedList.Builder<Key, Value>
The CoroutineDispatcher
defining where page loading updates are dispatched.
Parameters | |
---|---|
notifyDispatcher: CoroutineDispatcher |
|
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |
funsetNotifyExecutor(notifyExecutor: Executor): PagedList.Builder<Key, Value>
The Executor
defining where page loading updates are dispatched.
Parameters | |
---|---|
notifyExecutor: Executor |
|
Returns | |
---|---|
PagedList.Builder<Key, Value> |
this |