Presenter

public abstract class Presenter
extends Object implements FacetProvider

java.lang.Object
↳	android.support.v17.leanback.widget.Presenter

Known Direct Subclasses

AbstractDetailsDescriptionPresenter, DetailsOverviewLogoPresenter, DividerPresenter, RowHeaderPresenter, RowPresenter, VerticalGridPresenter

Known Indirect Subclasses

AbstractMediaItemPresenter, AbstractMediaListHeaderPresenter, DetailsOverviewRowPresenter, FullWidthDetailsOverviewRowPresenter, ListRowPresenter, PlaybackControlsRowPresenter

A Presenter is used to generate Views and bind Objects to them on demand. It is closely related to the concept of an RecyclerView.Adapter, but is not position-based. The leanback framework implements the adapter concept using ObjectAdapter which refers to a Presenter (or PresenterSelector) instance.

Presenters should be stateless. Presenters typically extend Presenter.ViewHolder to store all necessary view state information, such as references to child views to be used when binding to avoid expensive calls to findViewById(int).

A trivial Presenter that takes a string and renders it into a TextView:

 public class StringTextViewPresenter extends Presenter {
     // This class does not need a custom ViewHolder, since it does not use
     // a complex layout.

     @Override
     public ViewHolder onCreateViewHolder(ViewGroup parent) {
         return new ViewHolder(new TextView(parent.getContext()));
     }

     @Override
     public void onBindViewHolder(ViewHolder viewHolder, Object item) {
         String str = (String) item;
         TextView textView = (TextView) viewHolder.mView;

         textView.setText(item);
     }

     @Override
     public void onUnbindViewHolder(ViewHolder viewHolder) {
         // Nothing to unbind for TextView, but if this viewHolder had
         // allocated bitmaps, they can be released here.
     }
 }

In addition to view creation and binding, Presenter allows dynamic interface (facet) to be added: setFacet(Class, Object). Supported facets:

ItemAlignmentFacet is used by HorizontalGridView and VerticalGridView to customize child alignment.

Summary

Nested classes
`class`	`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.
`class`	`Presenter.ViewHolderTask` Base class to perform a task on Presenter.ViewHolder.

Public constructors
`Presenter()`

Public methods
`final Object`	`getFacet(Class<?> facetClass)` Queries optional implemented facet.
`abstract void`	`onBindViewHolder(Presenter.ViewHolder viewHolder, Object item)` Binds a `View` to an item.
`abstract Presenter.ViewHolder`	`onCreateViewHolder(ViewGroup parent)` Creates a new `View`.
`abstract void`	`onUnbindViewHolder(Presenter.ViewHolder viewHolder)` Unbinds a `View` from an item.
`void`	`onViewAttachedToWindow(Presenter.ViewHolder holder)` Called when a view created by this presenter has been attached to a window.
`void`	`onViewDetachedFromWindow(Presenter.ViewHolder holder)` Called when a view created by this presenter has been detached from its window.
`final void`	`setFacet(Class<?> facetClass, Object facetImpl)` Sets dynamic implemented facet in addition to basic Presenter functions.
`void`	`setOnClickListener(Presenter.ViewHolder holder, View.OnClickListener listener)` Called to set a click listener for the given view holder.

Protected methods
`static void`	`cancelAnimationsRecursive(View view)` Utility method for removing all running animations on a view.

Inherited methods

From class


  
    java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long millis, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
`final void`	`wait(long millis)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`final void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

From interface


  
    android.support.v17.leanback.widget.FacetProvider

Public constructors

Presenter

Presenter ()

Public methods

getFacet

Object getFacet (Class<?> facetClass)

Queries optional implemented facet.

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

Returns
`Object`	Facet implementation for the facetClass or null if feature not implemented.

onBindViewHolder

void onBindViewHolder (Presenter.ViewHolder viewHolder, 
                Object item)

Binds a View to an item.

Parameters
`viewHolder`	`Presenter.ViewHolder`
`item`	`Object`

onCreateViewHolder

Presenter.ViewHolder onCreateViewHolder (ViewGroup parent)

Creates a new View.

Parameters
`parent`	`ViewGroup`

Returns
`Presenter.ViewHolder`

onUnbindViewHolder

void onUnbindViewHolder (Presenter.ViewHolder viewHolder)

Unbinds a View from an item. Any expensive references may be released here, and any fields that are not bound for every item should be cleared here.

Parameters
`viewHolder`	`Presenter.ViewHolder`

onViewAttachedToWindow

void onViewAttachedToWindow (Presenter.ViewHolder holder)

Called when a view created by this presenter has been attached to a window.

This can be used as a reasonable signal that the view is about to be seen by the user. If the adapter previously freed any resources in onViewDetachedFromWindow(ViewHolder) those resources should be restored here.

Parameters
`holder`	`Presenter.ViewHolder`: Holder of the view being attached

onViewDetachedFromWindow

void onViewDetachedFromWindow (Presenter.ViewHolder holder)

Called when a view created by this presenter has been detached from its window.

Becoming detached from the window is not necessarily a permanent condition; the consumer of an presenter's views may choose to cache views offscreen while they are not visible, attaching and detaching them as appropriate.

Any view property animations should be cancelled here or the view may fail to be recycled.

Parameters
`holder`	`Presenter.ViewHolder`: Holder of the view being detached

setFacet

void setFacet (Class<?> facetClass, 
                Object facetImpl)

Sets dynamic implemented facet in addition to basic Presenter functions.

Parameters
`facetClass`	`Class`: Facet classes to query, can be class of `ItemAlignmentFacet`.
`facetImpl`	`Object`: Facet implementation.

setOnClickListener

void setOnClickListener (Presenter.ViewHolder holder, 
                View.OnClickListener listener)

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).

Parameters
`holder`	`Presenter.ViewHolder`: The view holder containing the view(s) on which the listener should be set.
`listener`	`View.OnClickListener`: The click listener to be set.

Protected methods

cancelAnimationsRecursive

void cancelAnimationsRecursive (View view)

Utility method for removing all running animations on a view.

Parameters
`view`	`View`

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Presenter

Summary

Nested classes

Public constructors

Public methods

Protected methods

Inherited methods

Public constructors

Presenter

Public methods

getFacet

onBindViewHolder

onCreateViewHolder

onUnbindViewHolder

onViewAttachedToWindow

onViewDetachedFromWindow

setFacet

setOnClickListener

Protected methods

cancelAnimationsRecursive

Interfaces

Classes