android.support.v4.view
Class ActionProvider

java.lang.Object
  extended by android.support.v4.view.ActionProvider

public abstract class ActionProvider
extends java.lang.Object

This class is a mediator for accomplishing a given task, for example sharing a file. It is responsible for creating a view that performs an action that accomplishes the task. This class also implements other functions such a performing a default action.

Note: This class is included in the support library for compatibility with API level 4 and higher. If you're developing your app for API level 14 and higher only, you should instead use the framework ActionProvider class.

An ActionProvider can be optionally specified for a MenuItem and in such a case it will be responsible for creating the action view that appears in the ActionBar as a substitute for the menu item when the item is displayed as an action item. Also the provider is responsible for performing a default action if a menu item placed on the overflow menu of the ActionBar is selected and none of the menu item callbacks has handled the selection. For this case the provider can also optionally provide a sub-menu for accomplishing the task at hand.

There are two ways for using an action provider for creating and handling of action views:

See Also:
MenuItemCompat.setActionProvider(android.view.MenuItem, ActionProvider), MenuItemCompat.getActionProvider(android.view.MenuItem)

Nested Class Summary
static interface ActionProvider.SubUiVisibilityListener
           
static interface ActionProvider.VisibilityListener
          Listens to changes in visibility as reported by refreshVisibility().
 
Constructor Summary
ActionProvider(android.content.Context context)
          Creates a new instance.
 
Method Summary
 android.content.Context getContext()
          Gets the context associated with this action provider.
 boolean hasSubMenu()
          Determines if this ActionProvider has a submenu associated with it.
 boolean isVisible()
          If overridesItemVisibility() returns true, the return value of this method will help determine the visibility of the MenuItem this ActionProvider is bound to.
abstract  android.view.View onCreateActionView()
          Factory method for creating new action views.
 android.view.View onCreateActionView(android.view.MenuItem forItem)
          Factory method called by the Android framework to create new action views.
 boolean onPerformDefaultAction()
          Performs an optional default action.
 void onPrepareSubMenu(android.view.SubMenu subMenu)
          Called to prepare an associated submenu for the menu item backed by this ActionProvider.
 boolean overridesItemVisibility()
          The result of this method determines whether or not isVisible() will be used by the MenuItem this ActionProvider is bound to help determine its visibility.
 void refreshVisibility()
          If this ActionProvider is associated with an item in a menu, refresh the visibility of the item based on overridesItemVisibility() and isVisible().
 void setSubUiVisibilityListener(ActionProvider.SubUiVisibilityListener listener)
           
 void setVisibilityListener(ActionProvider.VisibilityListener listener)
          Set a listener to be notified when this ActionProvider's overridden visibility changes.
 void subUiVisibilityChanged(boolean isVisible)
          Notify the system that the visibility of an action view's sub-UI such as an anchored popup has changed.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ActionProvider

public ActionProvider(android.content.Context context)
Creates a new instance.

Parameters:
context - Context for accessing resources.
Method Detail

getContext

public android.content.Context getContext()
Gets the context associated with this action provider.


onCreateActionView

public abstract android.view.View onCreateActionView()
Factory method for creating new action views.

Returns:
A new action view.

onCreateActionView

public android.view.View onCreateActionView(android.view.MenuItem forItem)
Factory method called by the Android framework to create new action views. This method returns a new action view for the given MenuItem.

If your ActionProvider implementation overrides the deprecated no-argument overload onCreateActionView(), overriding this method for devices running API 16 or later is recommended but optional. The default implementation calls onCreateActionView() for compatibility with applications written for older platform versions.

Parameters:
forItem - MenuItem to create the action view for
Returns:
the new action view

overridesItemVisibility

public boolean overridesItemVisibility()
The result of this method determines whether or not isVisible() will be used by the MenuItem this ActionProvider is bound to help determine its visibility.

Returns:
true if this ActionProvider overrides the visibility of the MenuItem it is bound to, false otherwise. The default implementation returns false.
See Also:
isVisible()

isVisible

public boolean isVisible()
If overridesItemVisibility() returns true, the return value of this method will help determine the visibility of the MenuItem this ActionProvider is bound to.

If the MenuItem's visibility is explicitly set to false by the application, the MenuItem will not be shown, even if this method returns true.

Returns:
true if the MenuItem this ActionProvider is bound to is visible, false if it is invisible. The default implementation returns true.

refreshVisibility

public void refreshVisibility()
If this ActionProvider is associated with an item in a menu, refresh the visibility of the item based on overridesItemVisibility() and isVisible(). If overridesItemVisibility() returns false, this call will have no effect.


onPerformDefaultAction

public boolean onPerformDefaultAction()
Performs an optional default action.

For the case of an action provider placed in a menu item not shown as an action this method is invoked if previous callbacks for processing menu selection has handled the event.

A menu item selection is processed in the following order:

The default implementation does not perform any action and returns false.


hasSubMenu

public boolean hasSubMenu()
Determines if this ActionProvider has a submenu associated with it.

Associated submenus will be shown when an action view is not. This provider instance will receive a call to onPrepareSubMenu(SubMenu) after the call to onPerformDefaultAction() and before a submenu is displayed to the user.

Returns:
true if the item backed by this provider should have an associated submenu

onPrepareSubMenu

public void onPrepareSubMenu(android.view.SubMenu subMenu)
Called to prepare an associated submenu for the menu item backed by this ActionProvider.

if hasSubMenu() returns true, this method will be called when the menu item is selected to prepare the submenu for presentation to the user. Apps may use this to create or alter submenu content right before display.

Parameters:
subMenu - Submenu that will be displayed

subUiVisibilityChanged

public void subUiVisibilityChanged(boolean isVisible)
Notify the system that the visibility of an action view's sub-UI such as an anchored popup has changed. This will affect how other system visibility notifications occur.


setSubUiVisibilityListener

public void setSubUiVisibilityListener(ActionProvider.SubUiVisibilityListener listener)

setVisibilityListener

public void setVisibilityListener(ActionProvider.VisibilityListener listener)
Set a listener to be notified when this ActionProvider's overridden visibility changes. This should only be used by MenuItem implementations.

Parameters:
listener - listener to set