RowPresenter
abstract class RowPresenter : Presenter
| kotlin.Any | ||
| ↳ | androidx.leanback.widget.Presenter | |
| ↳ | androidx.leanback.widget.RowPresenter | |
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 subclassRowPresenter.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 overrideonRowViewSelected(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 overrideonRowViewExpanded(ViewHolder, boolean).
Activated status
The activated status of a row is applied to the row view and its children viaView#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_EXPANDEDActivated status is synced with row expanded statusSYNC_ACTIVATED_TO_SELECTEDActivated status is synced with row selected statusSYNC_ACTIVATED_TO_EXPANDED_AND_SELECTEDActivated status is set to true when both expanded and selected status are trueSYNC_ACTIVATED_CUSTOMActivated status is not controlled by selected status or expanded status, application can control activated status by its own. Application should callRowPresenter.ViewHolder#setActivated(boolean)to change activated status of row view.
User events
RowPresenter providesOnItemViewSelectedListener 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 |
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| open |
A ViewHolder for a |
Constants |
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| static Int |
Don't synchronize row view activated status with selected status or expanded status, application will do its own through |
| static Int |
Synchronizes row view's activated status to expand status of the row view holder. |
| static Int |
Sets the row view's activated status to true when both expand and selected are true. |
| static Int |
Synchronizes row view's activated status to selected status of the row view holder. |
Public constructors |
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<init>()Constructs a RowPresenter. |
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Public methods |
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| open Unit |
freeze(holder: RowPresenter.ViewHolder!, freeze: Boolean)Freezes/unfreezes the row, typically used when a transition starts/ends. |
| RowHeaderPresenter! |
Returns the Presenter used for rendering the header, or null if none has been set. |
| RowPresenter.ViewHolder! |
getRowViewHolder(holder: Presenter.ViewHolder!)Returns the |
| Boolean |
Returns true if the row selection effect is enabled. |
| Float |
Returns the current select level. |
| Int |
Returns the policy of updating row view activated status. |
| open Boolean |
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 |
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| 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 |
| open Unit |
Called after a |
| open Boolean |
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 |
Invoked when the row view is attached to the window. |
| open Unit |
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 |
Callback when the select level changes. |
| open Unit |
Unbinds the given ViewHolder. |
Inherited functions |
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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:
SYNC_ACTIVATED_TO_EXPANDED SYNC_ACTIVATED_TO_SELECTED SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED SYNC_ACTIVATED_CUSTOMisUsingDefaultSelectEffect
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 |
RowPresenter.ViewHolder!: true if children of row participating in entrance transition should be set to visible, false otherwise. |
setHeaderPresenter
fun setHeaderPresenter(headerPresenter: RowHeaderPresenter!): Unit
Sets the Presenter used for rendering the header. Can be null to disable header rendering. The method must be called before creating any Row Views.
setRowViewExpanded
fun setRowViewExpanded(holder: Presenter.ViewHolder!, expanded: Boolean): Unit
Sets the expanded state of a Row view.
| Parameters | |
|---|---|
holder |
Presenter.ViewHolder!: The Row ViewHolder to set expanded state on. |
expanded |
Presenter.ViewHolder!: True if the Row is expanded, false otherwise. |
setRowViewSelected
fun setRowViewSelected(holder: Presenter.ViewHolder!, selected: Boolean): Unit
Sets the selected state of a Row view.
| Parameters | |
|---|---|
holder |
Presenter.ViewHolder!: The Row ViewHolder to set expanded state on. |
selected |
Presenter.ViewHolder!: True if the Row is expanded, false otherwise. |
setSelectEffectEnabled
fun setSelectEffectEnabled(applyDimOnSelect: Boolean): Unit
Enables or disables the row selection effect. This will not only affect the default dim effect, but subclasses must respect this flag as well.
setSelectLevel
fun setSelectLevel(vh: Presenter.ViewHolder!, level: Float): Unit
Sets the current select level to a value between 0 (unselected) and 1 (selected). Subclasses may override onSelectLevelChanged(ViewHolder) to respond to changes in the selected level.
setSyncActivatePolicy
fun setSyncActivatePolicy(syncActivatePolicy: Int): Unit
Sets the policy of updating row view activated status. Can be one of:
SYNC_ACTIVATED_TO_EXPANDED SYNC_ACTIVATED_TO_SELECTED SYNC_ACTIVATED_TO_EXPANDED_AND_SELECTED SYNC_ACTIVATED_CUSTOMProtected methods
createRowViewHolder
protected abstract fun createRowViewHolder(parent: ViewGroup!): RowPresenter.ViewHolder!
Called to create a ViewHolder object for a Row. Subclasses will override this method to return a different concrete ViewHolder object.
| Parameters | |
|---|---|
parent |
ViewGroup!: The parent View for the Row's view holder. |
| Return | |
|---|---|
| RowPresenter.ViewHolder!: A ViewHolder for the Row's View. |
dispatchItemSelectedListener
protected open fun dispatchItemSelectedListener(vh: RowPresenter.ViewHolder!, selected: Boolean): Unit
This method is only called from onRowViewSelected(ViewHolder, boolean) onRowViewSelected. The default behavior is to signal row selected events with a null item parameter. A Subclass of RowPresenter having child items should override this method and dispatch events with item information.
initializeRowViewHolder
protected open fun initializeRowViewHolder(vh: RowPresenter.ViewHolder!): Unit
Called after a RowPresenter.ViewHolder is created for a Row. Subclasses may override this method and start by calling super.initializeRowViewHolder(ViewHolder).
| Parameters | |
|---|---|
vh |
RowPresenter.ViewHolder!: The ViewHolder to initialize for the Row. |
isClippingChildren
protected open fun isClippingChildren(): Boolean
Returns true if the Row view should clip its children. The clipChildren flag is set on view in initializeRowViewHolder(ViewHolder). Note that Slide transition or explode transition need turn off clipChildren. Default value is false.
onBindRowViewHolder
protected open fun onBindRowViewHolder(vh: RowPresenter.ViewHolder!, item: Any!): Unit
Binds the given row object to the given ViewHolder. Derived classes of RowPresenter overriding onBindRowViewHolder(ViewHolder, Object) must call through the super class's implementation of this method.
onRowViewAttachedToWindow
protected open fun onRowViewAttachedToWindow(vh: RowPresenter.ViewHolder!): Unit
Invoked when the row view is attached to the window.
onRowViewDetachedFromWindow
protected open fun onRowViewDetachedFromWindow(vh: RowPresenter.ViewHolder!): Unit
Invoked when the row view is detached from the window.
onRowViewExpanded
protected open fun onRowViewExpanded(vh: RowPresenter.ViewHolder!, expanded: Boolean): Unit
Called when the row view's expanded state changes. A subclass may override this method to respond to expanded state changes of a Row. The default implementation will hide/show the header view. Subclasses may make visual changes to the Row View but must not create animation on the Row view.
onRowViewSelected
protected open fun onRowViewSelected(vh: RowPresenter.ViewHolder!, selected: Boolean): Unit
Called when the given row view changes selection state. A subclass may override this to respond to selected state changes of a Row. A subclass may make visual changes to Row view but must not create animation on the Row view.
onSelectLevelChanged
protected open fun onSelectLevelChanged(vh: RowPresenter.ViewHolder!): Unit
Callback when the select level changes. The default implementation applies the select level to RowHeaderPresenter#setSelectLevel(RowHeaderPresenter.ViewHolder, float) when getSelectEffectEnabled() is true. Subclasses may override this function and implement a different select effect. In this case, the method isUsingDefaultSelectEffect() should also be overridden to disable the default dimming effect.
onUnbindRowViewHolder
protected open fun onUnbindRowViewHolder(vh: RowPresenter.ViewHolder!): Unit
Unbinds the given ViewHolder. Derived classes of RowPresenter overriding onUnbindRowViewHolder(ViewHolder) must call through the super class's implementation of this method.