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23-Jun-2017 |
Chris Craik <ccraik@google.com> |
Initial commit of paging component.
This commit introduces a paging component to enable gradual, lazy
loading from large data sources, including Room queries.
The primary entry points are:
1) CountedDataSource, the base class for defining a countable (i.e.
fixed, known size) source of items, such as a Database query.
2) LazyList, the lazy-loading List-like component which pages content
in on a background thread from a CountedDataSource.
3) LiveLazyListProvider, the class which produces DataSources, and
presents a LiveData<LazyList<T>>.
4) LazyListAdapterHelper, which takes a LiveData<LazyList>, and
presents the data simply to an adapter. It computes differences
between versions with DiffUtil, and signalling updates to the adapter.
Currently, Room only presents a limit-offset query as an easy means to
get a LiveData of a LazyList, but it's possible to write a custom data
source to page in data from keyed (including composite-keyed) queries.
Test: new tests
Change-Id: I415879a032d83786d734c26c429828da3b8bc76a
/frameworks/support/room/runtime/src/main/java/android/arch/persistence/room/RoomSQLiteQuery.java
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