FacetProvider

Kotlin |Java

interface FacetProvider

androidx.leanback.widget.FacetProvider

Known Direct Subclasses

GuidedActionsStylist.ViewHolder, ItemBridgeAdapter.ViewHolder, Presenter, Presenter.ViewHolder

GuidedActionsStylist.ViewHolder	ViewHolder caches information about the action item layouts' subviews.
ItemBridgeAdapter.ViewHolder	ViewHolder for the ItemBridgeAdapter.
Presenter	A Presenter is used to generate `View`s and bind Objects to them on demand.
Presenter.ViewHolder	ViewHolder can be subclassed and used to cache any view accessors needed to improve binding performance (for example, results of findViewById) without needing to subclass a View.

Known Indirect Subclasses

AbstractDetailsDescriptionPresenter, AbstractDetailsDescriptionPresenter.ViewHolder, AbstractMediaItemPresenter, AbstractMediaItemPresenter.ViewHolder, AbstractMediaListHeaderPresenter, AbstractMediaListHeaderPresenter.ViewHolder, DetailsOverviewLogoPresenter, DetailsOverviewLogoPresenter.ViewHolder, DetailsOverviewRowPresenter, DetailsOverviewRowPresenter.ViewHolder, DividerPresenter, FullWidthDetailsOverviewRowPresenter, and 15 others.

AbstractDetailsDescriptionPresenter	An abstract `Presenter` for rendering a detailed description of an item.
AbstractDetailsDescriptionPresenter.ViewHolder	The ViewHolder for the `AbstractDetailsDescriptionPresenter`.
AbstractMediaItemPresenter	Abstract `Presenter` class for rendering media items in a playlist format.
AbstractMediaItemPresenter.ViewHolder	The ViewHolder for the `AbstractMediaItemPresenter`.
AbstractMediaListHeaderPresenter	Abstract presenter class for rendering the header for a list of media items in a playlist.
AbstractMediaListHeaderPresenter.ViewHolder	The ViewHolder for the `AbstractMediaListHeaderPresenter`.
DetailsOverviewLogoPresenter	Presenter that responsible to create a ImageView and bind to DetailsOverviewRow.
DetailsOverviewLogoPresenter.ViewHolder	ViewHolder for Logo view of DetailsOverviewRow.
DetailsOverviewRowPresenter	Renders a `DetailsOverviewRow` to display an overview of an item.
DetailsOverviewRowPresenter.ViewHolder	A ViewHolder for the DetailsOverviewRow.
DividerPresenter	DividerPresenter provides a default presentation for `DividerRow` in HeadersFragment.
FullWidthDetailsOverviewRowPresenter	Renders a `DetailsOverviewRow` to display an overview of an item.
FullWidthDetailsOverviewRowPresenter.ViewHolder	A ViewHolder for the DetailsOverviewRow.
ListRowPresenter	ListRowPresenter renders `ListRow` using a `HorizontalGridView` hosted in a `ListRowView`.
ListRowPresenter.ViewHolder	ViewHolder for the ListRowPresenter.
PlaybackControlsRowPresenter	A PlaybackControlsRowPresenter renders a `PlaybackControlsRow` to display a series of playback control buttons.
PlaybackControlsRowPresenter.ViewHolder	A ViewHolder for the PlaybackControlsRow.
PlaybackRowPresenter	Subclass of `RowPresenter` that can define the desired behavior when the view reappears.
PlaybackRowPresenter.ViewHolder	This container is used for trapping click events and passing them to the playback controls.
PlaybackTransportRowPresenter	A PlaybackTransportRowPresenter renders a `PlaybackControlsRow` to display a series of playback control buttons.
PlaybackTransportRowPresenter.ViewHolder	A ViewHolder for the PlaybackControlsRow supporting seek UI.
RowHeaderPresenter	RowHeaderPresenter provides a default presentation for `HeaderItem` using a `RowHeaderView` and optionally a TextView for description.
RowHeaderPresenter.ViewHolder	A ViewHolder for the RowHeaderPresenter.
RowPresenter	An abstract `Presenter` that renders an Object in RowsFragment, the object can be subclass `Row` or a generic one.
RowPresenter.ViewHolder	A ViewHolder for a `Row`.
VerticalGridPresenter	A presenter that renders objects in a `VerticalGridView`.
VerticalGridPresenter.ViewHolder	ViewHolder for the VerticalGridPresenter.

This is the query interface to supply optional features(aka facets) on an object without the need of letting the object to subclass or implement java interfaces. Facets allow leanback to re-compose optional features from leanback ViewHolder to RecyclerView ViewHolder. A typical "facet" class is ItemAlignmentFacet that defines how to align a ViewHolder inside VerticalGridView or HorizontalGridView. A FacetProvider could be retrieved from two sources by VerticalGridView/HorizontalGridView in the following order.

ViewHolder based facet:

RecyclerView.ViewHolder can implement FacetProvider. If app uses leanback Presenter.ViewHolder, the facet of Presenter.ViewHolder will be relayed by ItemBridgeAdapter.ViewHolder which is a wrapper of Presenter.ViewHolder. ViewHolder based facet is used less frequently than item view type based facet because in most cases ViewHolders of same type share the same alignment definition.

For example, app calls viewHolder.setFacet(ItemAlignmentFacet.class, itemAlignmentFacet) to set alignment of the ViewHolder instance.

RecyclerView item view type based facet:

RecyclerView.Adapter can implement FacetProviderAdapter which returns FacetProvider for each item view type. If app uses leanback ObjectAdapter and Presenter, app wraps the ObjectAdapter and Presenter using ItemBridgeAdapter. The implementation of ItemBridgeAdapter#getFacetProvider(int) will return the FacetProvider implemented by Presenter which is mapped to the item view type.

For example, app calls presenter.setFacet(ItemAlignmentFacet.class, itemAlignmentFacet) to set alignment of all ViewHolders created by this Presenter.

Summary

Public methods
abstract Any!	`getFacet(facetClass: Class<*>!)` Queries optional implemented facet.

Public methods

getFacet

abstract fun getFacet(facetClass: Class<*>!): Any!

Queries optional implemented facet.

Parameters
`facetClass`	Class<*>!: Facet classes to query, examples are: class of `ItemAlignmentFacet`.

Return
`Any!`	Facet implementation for the facetClass or null if feature not implemented.