public abstract class ActionProvider extends Object
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:
MenuItem
directly by
calling MenuItemCompat.setActionProvider(android.view.MenuItem, ActionProvider)
.
<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" />
To create a custom action provider, extend ActionProvider and implement its callback methods as necessary. In particular, implement the following methods:
ActionProvider()
constructoronCreateActionView(MenuItem)
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()
.
Modifier and Type | Class and Description |
---|---|
static interface |
ActionProvider.SubUiVisibilityListener |
static interface |
ActionProvider.VisibilityListener
Listens to changes in visibility as reported by
refreshVisibility() . |
Constructor and Description |
---|
ActionProvider(Context context)
Creates a new instance.
|
Modifier and Type | Method and Description |
---|---|
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(MenuItem forItem)
Factory method called by the Android framework to create new action views.
|
boolean |
onPerformDefaultAction()
Performs an optional default action.
|
void |
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. |
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 |
reset() |
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.
|
public ActionProvider(Context context)
context
- Context for accessing resources.public Context getContext()
public abstract View onCreateActionView()
public View onCreateActionView(MenuItem forItem)
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.
forItem
- MenuItem to create the action view forpublic boolean overridesItemVisibility()
isVisible()
will be used
by the MenuItem
this ActionProvider is bound to help determine its visibility.isVisible()
public boolean isVisible()
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.
public void refreshVisibility()
overridesItemVisibility()
and
isVisible()
. If overridesItemVisibility()
returns false, this call
will have no effect.public boolean onPerformDefaultAction()
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:
MenuItem.OnMenuItemClickListener.onMenuItemClick
.Activity.onOptionsItemSelected(android.view.MenuItem)
FragmentActivity.onOptionsItemSelected(MenuItem)}
Fragment.onOptionsItemSelected(android.view.MenuItem)
Fragment.onOptionsItemSelected(MenuItem)}Intent
set via
MenuItem.setIntent(android.content.Intent)
The default implementation does not perform any action and returns false.
public boolean hasSubMenu()
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.
public void onPrepareSubMenu(SubMenu subMenu)
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.
subMenu
- Submenu that will be displayedpublic void subUiVisibilityChanged(boolean isVisible)
public void setSubUiVisibilityListener(ActionProvider.SubUiVisibilityListener listener)
public void setVisibilityListener(ActionProvider.VisibilityListener listener)
listener
- listener to setpublic void reset()