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ActionProvider.javaAPI DocAndroid 5.1 API9486Thu Mar 12 22:22:10 GMT 2015android.view

ActionProvider

public abstract class ActionProvider extends Object
An ActionProvider defines rich menu interaction in a single component. ActionProvider can generate action views for use in the action bar, dynamically populate submenus of a MenuItem, and handle default menu item invocations.

An ActionProvider can be optionally specified for a {@link MenuItem} and will be responsible for creating the action view that appears in the {@link android.app.ActionBar} in place of a simple button in the bar. When the menu item is presented in a way that does not allow custom action views, (e.g. in an overflow menu,) the ActionProvider can perform a default action.

There are two ways to use an action provider:

  • Set the action provider on a {@link MenuItem} directly by calling {@link MenuItem#setActionProvider(ActionProvider)}.
  • Declare the action provider in an XML menu resource. For example: 
    
<item android:id="@+id/my_menu_item"
android:title="Title"
android:icon="@drawable/my_menu_item_icon"
android:showAsAction="ifRoom"
android:actionProviderClass="foo.bar.SomeActionProvider" />

see
MenuItem#setActionProvider(ActionProvider)
see
MenuItem#getActionProvider()

Fields Summary
private static final String
TAG
private SubUiVisibilityListener
mSubUiVisibilityListener
private VisibilityListener
mVisibilityListener
Constructors Summary
public ActionProvider(android.content.Context context)
Creates a new instance. ActionProvider classes should always implement a constructor that takes a single Context parameter for inflating from menu XML.

param
context Context for accessing resources.
Methods Summary
public booleanhasSubMenu()
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 {@link #onPrepareSubMenu(SubMenu)} after the call to {@link #onPerformDefaultAction()} and before a submenu is displayed to the user.

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

        return false;
public booleanisVisible()
If {@link #overridesItemVisibility()} returns true, the return value of this method will help determine the visibility of the {@link 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.

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

        return true;
public abstract ViewonCreateActionView()
Factory method called by the Android framework to create new action views.

This method has been deprecated in favor of {@link #onCreateActionView(MenuItem)}. Newer apps that wish to support platform versions prior to API 16 should also implement this method to return a valid action view.

return
A new action view.
deprecated
use {@link #onCreateActionView(MenuItem)}

public ViewonCreateActionView(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
{@link #onCreateActionView()}, overriding this method for devices running API 16 or later
is recommended but optional. The default implementation calls {@link #onCreateActionView()}
for compatibility with applications written for older platform versions.
param
forItem MenuItem to create the action view for
return
the new action view
        return onCreateActionView();
    
public booleanonPerformDefaultAction()
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:

    

  • 
Receiving a call to {@link MenuItem.OnMenuItemClickListener#onMenuItemClick
MenuItem.OnMenuItemClickListener.onMenuItemClick}.

    • 

  • 
Receiving a call to {@link android.app.Activity#onOptionsItemSelected(MenuItem)
Activity.onOptionsItemSelected(MenuItem)}

    • 

  • 
Receiving a call to {@link android.app.Fragment#onOptionsItemSelected(MenuItem)
Fragment.onOptionsItemSelected(MenuItem)}

    • 

  • 
Launching the {@link android.content.Intent} set via
{@link MenuItem#setIntent(android.content.Intent) MenuItem.setIntent(android.content.Intent)}

    • 

  • 
Invoking this method.

    • 






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

        return false;
    
public voidonPrepareSubMenu(SubMenu subMenu)
Called to prepare an associated submenu for the menu item backed by this ActionProvider.


if {@link #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.
param
subMenu Submenu that will be displayed
    
public booleanoverridesItemVisibility()
The result of this method determines whether or not {@link #isVisible()} will be used
by the {@link MenuItem} this ActionProvider is bound to help determine its visibility.
return
true if this ActionProvider overrides the visibility of the MenuItem
it is bound to, false otherwise. The default implementation returns false.
see
#isVisible()
        return false;
    
public voidrefreshVisibility()
If this ActionProvider is associated with an item in a menu,
refresh the visibility of the item based on {@link #overridesItemVisibility()} and
{@link #isVisible()}. If {@link #overridesItemVisibility()} returns false, this call
will have no effect.
        if (mVisibilityListener != null && overridesItemVisibility()) {
            mVisibilityListener.onActionProviderVisibilityChanged(isVisible());
        }
    
public voidsetSubUiVisibilityListener(android.view.ActionProvider$SubUiVisibilityListener listener)
hide
Internal use only
        mSubUiVisibilityListener = listener;
    
public voidsetVisibilityListener(android.view.ActionProvider$VisibilityListener listener)
Set a listener to be notified when this ActionProvider's overridden visibility changes.
This should only be used by MenuItem implementations.
param
listener listener to set
        if (mVisibilityListener != null) {
            Log.w(TAG, "setVisibilityListener: Setting a new ActionProvider.VisibilityListener " +
                    "when one is already set. Are you reusing this " + getClass().getSimpleName() +
                    " instance while it is still in use somewhere else?");
        }
        mVisibilityListener = listener;
    
public voidsubUiVisibilityChanged(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.
hide
Pending future API approval
        if (mSubUiVisibilityListener != null) {
            mSubUiVisibilityListener.onSubUiVisibilityChanged(isVisible);
        }