RowPresenter

Kotlin |Java

abstract class RowPresenter : Presenter

kotlin.Any
↳	androidx.leanback.widget.Presenter
	↳	androidx.leanback.widget.RowPresenter

Known Direct Subclasses

AbstractMediaItemPresenter, AbstractMediaListHeaderPresenter, DetailsOverviewRowPresenter, FullWidthDetailsOverviewRowPresenter, ListRowPresenter, PlaybackRowPresenter

AbstractMediaItemPresenter	Abstract `Presenter` class for rendering media items in a playlist format.
AbstractMediaListHeaderPresenter	Abstract presenter class for rendering the header for a list of media items in a playlist.
DetailsOverviewRowPresenter	Renders a `DetailsOverviewRow` to display an overview of an item.
FullWidthDetailsOverviewRowPresenter	Renders a `DetailsOverviewRow` to display an overview of an item.
ListRowPresenter	ListRowPresenter renders `ListRow` using a `HorizontalGridView` hosted in a `ListRowView`.
PlaybackRowPresenter	Subclass of `RowPresenter` that can define the desired behavior when the view reappears.

Known Indirect Subclasses

PlaybackControlsRowPresenter, PlaybackTransportRowPresenter

PlaybackControlsRowPresenter	A PlaybackControlsRowPresenter renders a `PlaybackControlsRow` to display a series of playback control buttons.
PlaybackTransportRowPresenter	A PlaybackTransportRowPresenter renders a `PlaybackControlsRow` to display a series of playback control buttons.

An abstract Presenter that renders an Object in RowsFragment, the object can be subclass Row or a generic one. When the object is not Row class, ViewHolder#getRow() returns null.

Customize UI widgets

When a subclass of RowPresenter adds UI widgets, it should subclass RowPresenter.ViewHolder and override createRowViewHolder(ViewGroup) and initializeRowViewHolder(ViewHolder). The subclass must use layout id "row_content" for the widget that will be aligned to the title of any HeadersFragment that may exist in the parent fragment. RowPresenter contains an optional and replaceable RowHeaderPresenter that renders the header. You can disable the default rendering or replace the Presenter with a new header presenter by calling setHeaderPresenter(RowHeaderPresenter).

UI events from fragments

RowPresenter receives calls from its parent (typically a Fragment) when:

A row is selected via setRowViewSelected(Presenter.ViewHolder, boolean). The event is triggered immediately when there is a row selection change before the selection animation is started. Selected status may control activated status of the row (see "Activated status" below). Subclasses of RowPresenter may override onRowViewSelected(ViewHolder, boolean).
A row is expanded to full height via setRowViewExpanded(Presenter.ViewHolder, boolean) when BrowseFragment hides fast lane on the left. The event is triggered immediately before the expand animation is started. Row title is shown when row is expanded. Expanded status may control activated status of the row (see "Activated status" below). Subclasses of RowPresenter may override onRowViewExpanded(ViewHolder, boolean).

Activated status

The activated status of a row is applied to the row view and its children via View#setActivated(boolean). The activated status is typically used to control BaseCardView info region visibility. The row's activated status can be controlled by selected status and/or expanded status. Call setSyncActivatePolicy(int) and choose one of the four policies:

SYNC_ACTIVATED_TO_EXPANDED Activated status is synced with row expanded status
SYNC_ACTIVATED_TO_SELECTED Activated status is synced with row selected status
SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED Activated status is set to true when both expanded and selected status are true
SYNC_ACTIVATED_CUSTOM Activated status is not controlled by selected status or expanded status, application can control activated status by its own. Application should call RowPresenter.ViewHolder#setActivated(boolean) to change activated status of row view.

User events

RowPresenter provides OnItemViewSelectedListener and OnItemViewClickedListener. If a subclass wants to add its own View.OnFocusChangeListener or View.OnClickListener, it must do that in createRowViewHolder(ViewGroup) to be properly chained by the library. Adding View listeners after createRowViewHolder(ViewGroup) is undefined and may result in incorrect behavior by the library's listeners.

Selection animation

When a user scrolls through rows, a fragment will initiate animation and call setSelectLevel(Presenter.ViewHolder, float) with float value between 0 and 1. By default, the RowPresenter draws a dim overlay on top of the row view for views that are not selected. Subclasses may override this default effect by having isUsingDefaultSelectEffect() return false and overriding onSelectLevelChanged(ViewHolder) to apply a different selection effect.

Call setSelectEffectEnabled(boolean) to enable/disable the select effect, This will not only enable/disable the default dim effect but also subclasses must respect this flag as well.

Summary

Nested classes
open	`ViewHolder` A ViewHolder for a `Row`.

Constants
static Int	`SYNC_ACTIVATED_CUSTOM` Don't synchronize row view activated status with selected status or expanded status, application will do its own through `RowPresenter.ViewHolder#setActivated(boolean)`.
static Int	`SYNC_ACTIVATED_TO_EXPANDED` Synchronizes row view's activated status to expand status of the row view holder.
static Int	`SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED` Sets the row view's activated status to true when both expand and selected are true.
static Int	`SYNC_ACTIVATED_TO_SELECTED` Synchronizes row view's activated status to selected status of the row view holder.

Public constructors
`<init>()` Constructs a RowPresenter.

Public methods
open Unit	`freeze(holder: RowPresenter.ViewHolder!, freeze: Boolean)` Freezes/unfreezes the row, typically used when a transition starts/ends.
RowHeaderPresenter!	`getHeaderPresenter()` Returns the Presenter used for rendering the header, or null if none has been set.
RowPresenter.ViewHolder!	`getRowViewHolder(holder: Presenter.ViewHolder!)` Returns the `RowPresenter.ViewHolder` from the given RowPresenter ViewHolder.
Boolean	`getSelectEffectEnabled()` Returns true if the row selection effect is enabled.
Float	`getSelectLevel(vh: Presenter.ViewHolder!)` Returns the current select level.
Int	`getSyncActivatePolicy()` Returns the policy of updating row view activated status.
open Boolean	`isUsingDefaultSelectEffect()` Returns true if this RowPresenter is using the default dimming effect.
Unit	`onBindViewHolder(viewHolder: Presenter.ViewHolder!, item: Any!)`
Presenter.ViewHolder!	`onCreateViewHolder(parent: ViewGroup!)`
Unit	`onUnbindViewHolder(viewHolder: Presenter.ViewHolder!)`
Unit	`onViewAttachedToWindow(holder: Presenter.ViewHolder!)`
Unit	`onViewDetachedFromWindow(holder: Presenter.ViewHolder!)`
open Unit	`setEntranceTransitionState(holder: RowPresenter.ViewHolder!, afterEntrance: Boolean)` Changes the visibility of views.
Unit	`setHeaderPresenter(headerPresenter: RowHeaderPresenter!)` Sets the Presenter used for rendering the header.
Unit	`setRowViewExpanded(holder: Presenter.ViewHolder!, expanded: Boolean)` Sets the expanded state of a Row view.
Unit	`setRowViewSelected(holder: Presenter.ViewHolder!, selected: Boolean)` Sets the selected state of a Row view.
Unit	`setSelectEffectEnabled(applyDimOnSelect: Boolean)` Enables or disables the row selection effect.
Unit	`setSelectLevel(vh: Presenter.ViewHolder!, level: Float)` Sets the current select level to a value between 0 (unselected) and 1 (selected).
Unit	`setSyncActivatePolicy(syncActivatePolicy: Int)` Sets the policy of updating row view activated status.

Protected methods
abstract RowPresenter.ViewHolder!	`createRowViewHolder(parent: ViewGroup!)` Called to create a ViewHolder object for a Row.
open Unit	`dispatchItemSelectedListener(vh: RowPresenter.ViewHolder!, selected: Boolean)` This method is only called from `onRowViewSelected(ViewHolder, boolean)` onRowViewSelected.
open Unit	`initializeRowViewHolder(vh: RowPresenter.ViewHolder!)` Called after a `RowPresenter.ViewHolder` is created for a Row.
open Boolean	`isClippingChildren()` Returns true if the Row view should clip its children.
open Unit	`onBindRowViewHolder(vh: RowPresenter.ViewHolder!, item: Any!)` Binds the given row object to the given ViewHolder.
open Unit	`onRowViewAttachedToWindow(vh: RowPresenter.ViewHolder!)` Invoked when the row view is attached to the window.
open Unit	`onRowViewDetachedFromWindow(vh: RowPresenter.ViewHolder!)` Invoked when the row view is detached from the window.
open Unit	`onRowViewExpanded(vh: RowPresenter.ViewHolder!, expanded: Boolean)` Called when the row view's expanded state changes.
open Unit	`onRowViewSelected(vh: RowPresenter.ViewHolder!, selected: Boolean)` Called when the given row view changes selection state.
open Unit	`onSelectLevelChanged(vh: RowPresenter.ViewHolder!)` Callback when the select level changes.
open Unit	`onUnbindRowViewHolder(vh: RowPresenter.ViewHolder!)` Unbinds the given ViewHolder.

Inherited functions

From class Presenter

`Unit`	`cancelAnimationsRecursive(view: View!)` Utility method for removing all running animations on a view.
`Any!`	`getFacet(facetClass: Class<*>!)`
`Unit`	`onBindViewHolder(viewHolder: Presenter.ViewHolder!, item: Any!, payloads: MutableList<Any!>!)` Binds a `View` to an item with a list of payloads.
`Unit`	`setFacet(facetClass: Class<*>!, facetImpl: Any!)` Sets dynamic implemented facet in addition to basic Presenter functions.
`Unit`	`setOnClickListener(holder: Presenter.ViewHolder!, listener: OnClickListener!)` Called to set a click listener for the given view holder. The default implementation sets the click listener on the root view in the view holder. If the root view isn't focusable this method should be overridden to set the listener on the appropriate focusable child view(s).

Constants

SYNC_ACTIVATED_CUSTOM

static val SYNC_ACTIVATED_CUSTOM: Int

Don't synchronize row view activated status with selected status or expanded status, application will do its own through RowPresenter.ViewHolder#setActivated(boolean).

Value: 0

SYNC_ACTIVATED_TO_EXPANDED

static val SYNC_ACTIVATED_TO_EXPANDED: Int

Synchronizes row view's activated status to expand status of the row view holder.

Value: 1

SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED

static val SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED: Int

Sets the row view's activated status to true when both expand and selected are true.

Value: 3

SYNC_ACTIVATED_TO_SELECTED

static val SYNC_ACTIVATED_TO_SELECTED: Int

Synchronizes row view's activated status to selected status of the row view holder.

Value: 2

Public constructors

<init>

RowPresenter()

Constructs a RowPresenter.

Public methods

freeze

open fun freeze(
    holder: RowPresenter.ViewHolder!, 
    freeze: Boolean
): Unit

Freezes/unfreezes the row, typically used when a transition starts/ends. This method is called by the fragment, it should not call it directly by the application.

getHeaderPresenter

fun getHeaderPresenter(): RowHeaderPresenter!

Returns the Presenter used for rendering the header, or null if none has been set.

getRowViewHolder

fun getRowViewHolder(holder: Presenter.ViewHolder!): RowPresenter.ViewHolder!

Returns the RowPresenter.ViewHolder from the given RowPresenter ViewHolder.

getSelectEffectEnabled

fun getSelectEffectEnabled(): Boolean

Returns true if the row selection effect is enabled. This value not only determines whether the default dim implementation is used, but subclasses must also respect this flag.

getSelectLevel

fun getSelectLevel(vh: Presenter.ViewHolder!): Float

Returns the current select level. The value will be between 0 (unselected) and 1 (selected).

getSyncActivatePolicy

fun getSyncActivatePolicy(): Int

Returns the policy of updating row view activated status. Can be one of:

Default value SYNC_ACTIVATED_TO_EXPANDED

SYNC_ACTIVATED_TO_SELECTED

SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED

SYNC_ACTIVATED_CUSTOM

isUsingDefaultSelectEffect

open fun isUsingDefaultSelectEffect(): Boolean

Returns true if this RowPresenter is using the default dimming effect. A subclass may (most likely) return false and override onSelectLevelChanged(ViewHolder).

onBindViewHolder

fun onBindViewHolder(
    viewHolder: Presenter.ViewHolder!, 
    item: Any!
): Unit

onCreateViewHolder

fun onCreateViewHolder(parent: ViewGroup!): Presenter.ViewHolder!

onUnbindViewHolder

fun onUnbindViewHolder(viewHolder: Presenter.ViewHolder!): Unit

onViewAttachedToWindow

fun onViewAttachedToWindow(holder: Presenter.ViewHolder!): Unit

onViewDetachedFromWindow

fun onViewDetachedFromWindow(holder: Presenter.ViewHolder!): Unit

setEntranceTransitionState

open fun setEntranceTransitionState(
    holder: RowPresenter.ViewHolder!, 
    afterEntrance: Boolean
): Unit

Changes the visibility of views. The entrance transition will be run against the views that change visibilities. A subclass may override and begin with calling super.setEntranceTransitionState(). This method is called by the fragment, it should not be called directly by the application.

Parameters
`holder`	RowPresenter.ViewHolder!: The ViewHolder of the row.
`afterEntrance`	Boolean: true if children of row participating in entrance transition should be set to visible, false otherwise.

setHeaderPresenter

fun setHeaderPresenter(