ActionProvider

Artifact: androidx.core:core

View Source

Added in 1.1.0

---

Kotlin |Java

abstract class ActionProvider

Known direct subclasses

MediaRouteActionProvider, ShareActionProvider

MediaRouteActionProvider	The media route action provider displays a media route button in the application's ActionBar to allow the user to select routes and to control the currently selected route.
ShareActionProvider	Provides a share action, which is suitable for an activity's app bar.

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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.

An ActionProvider can be optionally specified for a android.view.MenuItem and in such a case it will be responsible for creating the action view that appears in the 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 android.view.MenuItem directly by calling setActionProvider.
• 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" />

### Creating a custom action provider

To create a custom action provider, extend ActionProvider and implement its callback methods as necessary. In particular, implement the following methods:

ActionProvider() constructor

This constructor is passed the application context. You should save the context in a member field to use in the other callback methods.

onCreateActionView(MenuItem)

The system calls this method when the action provider is created. You define the action provider's layout through the implementation of this method. Use the context acquired from the constructor to instantiate a android.view.LayoutInflater and inflate your action provider's layout from an XML resource, then hook up event listeners for the view's components. For example:

public View onCreateActionView(MenuItem forItem) {
    // Inflate the action provider to be shown on the action bar.
    LayoutInflater layoutInflater = LayoutInflater.from(mContext);
    View providerView =
        layoutInflater.inflate(R.layout.my_action_provider, null);
    ImageButton button =
        (ImageButton) providerView.findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // Do something...
        }
    });
    return providerView;
}

onPerformDefaultAction()

The system calls this method when the user selects a menu item from the action overflow. The action provider should perform a default action for the menu item. The system does not call this method if the menu item opens a submenu.

If your action provider presents a submenu through the onPrepareSubMenu() callback, the submenu appears even if the action provider is in the overflow menu. Thus, the system never calls onPerformDefaultAction() if there is a submenu.

Note: An activity or a fragment that implements onOptionsItemSelected() can override the action provider's default behavior (unless it uses a submenu) by handling the item-selected event and returning true. In this case, the system does not call onPerformDefaultAction().

See also
setActionProvider
getActionProvider

Summary

Nested types
interface ActionProvider.VisibilityListener Listens to changes in visibility as reported by refreshVisibility.

Public constructors
ActionProvider(context: Context) Creates a new instance.

Public functions
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 View	onCreateActionView() Factory method for creating new action views.
View	onCreateActionView(forItem: MenuItem) Factory method called by the Android framework to create new action views.
Boolean	onPerformDefaultAction() Performs an optional default action.
Unit	onPrepareSubMenu(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.
Unit	refreshVisibility() If this ActionProvider is associated with an item in a menu, refresh the visibility of the item based on overridesItemVisibility and isVisible.
Unit	setVisibilityListener(listener: ActionProvider.VisibilityListener?) Set a listener to be notified when this ActionProvider's overridden visibility changes.

Public constructors

ActionProvider

Added in 1.1.0

ActionProvider(context: Context)

Creates a new instance.

Parameters
context: Context	Context for accessing resources.

Public functions

getContext

Added in 1.1.0

fun getContext(): Context

Gets the context associated with this action provider.

hasSubMenu

Added in 1.1.0

fun hasSubMenu(): Boolean

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 after the call to onPerformDefaultAction and before a submenu is displayed to the user.

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

isVisible

Added in 1.1.0

fun isVisible(): Boolean

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

onCreateActionView

Added in 1.1.0

abstract fun onCreateActionView(): View

Factory method for creating new action views.

Returns
View	A new action view.

onCreateActionView

Added in 1.1.0

fun onCreateActionView(forItem: MenuItem): View

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	MenuItem to create the action view for

Returns
View	the new action view

onPerformDefaultAction

Added in 1.1.0

fun onPerformDefaultAction(): Boolean

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 MenuItem.OnMenuItemClickListener.onMenuItemClick.
• Receiving a call to onOptionsItemSelected FragmentActivity.onOptionsItemSelected(MenuItem)}
• Receiving a call to onOptionsItemSelected Fragment.onOptionsItemSelected(MenuItem)}
• Launching the android.content.Intent set via MenuItem.setIntent(android.content.Intent)
• Invoking this method.

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

onPrepareSubMenu

Added in 1.1.0

fun onPrepareSubMenu(subMenu: SubMenu): Unit

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	Submenu that will be displayed

overridesItemVisibility

Added in 1.1.0

fun overridesItemVisibility(): Boolean

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
Boolean	true if this ActionProvider overrides the visibility of the MenuItem it is bound to, false otherwise. The default implementation returns false.

See also
isVisible

refreshVisibility

Added in 1.1.0

fun refreshVisibility(): Unit

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.

setVisibilityListener

Added in 1.1.0

fun setVisibilityListener(listener: ActionProvider.VisibilityListener?): Unit

Set a listener to be notified when this ActionProvider's overridden visibility changes. This should only be used by MenuItem implementations.

Parameters
listener: ActionProvider.VisibilityListener?	listener to set