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ActionProvider.javaAPI DocAndroid 5.1 API10178Thu Mar 12 22:22:56 GMT 2015android.support.v4.view

ActionProvider

public abstract class ActionProvider extends 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 {@link android.view.ActionProvider} class.

An ActionProvider can be optionally specified for a {@link android.view.MenuItem} and in such a case it will be responsible for creating the action view that appears in the {@link android.app.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:

  • Setting the action provider on a {@link android.view.MenuItem} directly by calling {@link android.support.v4.view.MenuItemCompat#setActionProvider(android.view.MenuItem, ActionProvider)}.
  • Declaring the action provider in the menu XML resource. For example: 
    
<item android:id="@+id/my_menu_item"
android:title="@string/my_menu_item_title"
android:icon="@drawable/my_menu_item_icon"
android:showAsAction="ifRoom"
android:actionProviderClass="foo.bar.SomeActionProvider" />

see
android.support.v4.view.MenuItemCompat#setActionProvider(android.view.MenuItem, ActionProvider)
see
android.support.v4.view.MenuItemCompat#getActionProvider(android.view.MenuItem)

Fields Summary
private static final String
TAG
private final android.content.Context
mContext
private SubUiVisibilityListener
mSubUiVisibilityListener
private VisibilityListener
mVisibilityListener
Constructors Summary
public ActionProvider(android.content.Context context)
Creates a new instance.

param
context Context for accessing resources.


                   
       
        mContext = context;
Methods Summary
public android.content.ContextgetContext()
Gets the context associated with this action provider.

        return mContext;
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 android.view.ViewonCreateActionView()
Factory method for creating new action views.

return
A new action view.

public android.view.ViewonCreateActionView(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
{@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 android.view.MenuItem.OnMenuItemClickListener#onMenuItemClick
MenuItem.OnMenuItemClickListener.onMenuItemClick}.
    • 


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

    • 


  • Receiving a call to
{@link android.support.v4.app.Fragment#onOptionsItemSelected(android.view.MenuItem)}
Fragment.onOptionsItemSelected(MenuItem)}
    • 


  • Launching the {@link android.content.Intent} set via
{@link android.view.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(android.view.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.support.v4.view.ActionProvider$SubUiVisibilityListener listener)
hide
Internal use only
        mSubUiVisibilityListener = listener;
    
public voidsetVisibilityListener(android.support.v4.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 && listener != 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);
        }