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am 92dbad8a: am b4d2e42a: docs: revise menu guide to focus more on using menu resources instead of defining menus in code. And revise some style.

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Merge commit '92dbad8ab0c8e242c4c3e52c339ed3296ae7901c' into gingerbread-plus-aosp

* commit '92dbad8ab0c8e242c4c3e52c339ed3296ae7901c':
  docs: revise menu guide to focus more on using menu resources
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Scott Main
2010-06-30 15:32:28 -07:00
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@@ -5,198 +5,324 @@ parent.link=index.html
<div id="qv-wrapper"> <div id="qv-wrapper">
<div id="qv"> <div id="qv">
<h2>Key classes</h2>
<ol>
<li>{@link android.view.Menu}</li>
<li>{@link android.view.ContextMenu}</li>
<li>{@link android.view.SubMenu}</li>
</ol>
<h2>In this document</h2> <h2>In this document</h2>
<ol> <ol>
<li><a href="#options-menu">Options Menu</a></li> <li><a href="#xml">Defining Menus</a></li>
<li><a href="#context-menu">Context Menu</a></li> <li><a href="#Inflating">Inflating a Menu Resource</a>
<li><a href="#submenu">Submenu</a></li> <li><a href="#options-menu">Creating an Options Menu</a>
<li><a href="#xml">Define Menus in XML</a></li> <ol>
<li><a href="#features">Menu Features</a> <li><a href="#ChangingTheMenu">Changing the menu when it opens</a></li>
</ol>
</li>
<li><a href="#context-menu">Creating a Context Menu</a></li>
<li><a href="#submenu">Creating a Submenu</a></li>
<li><a href="#features">Other Menu Features</a>
<ol> <ol>
<li><a href="#groups">Menu groups</a></li> <li><a href="#groups">Menu groups</a></li>
<li><a href="#checkable">Checkable menu items</a></li> <li><a href="#checkable">Checkable menu items</a></li>
<li><a href="#shortcuts">Shortcut keys</a></li> <li><a href="#shortcuts">Shortcut keys</a></li>
<li><a href="#intents">Menu item intents</a></li> <li><a href="#intents">Intents for menu items</a></li>
</ol> </ol>
</li> </li>
</ol> </ol>
<h2>Key classes</h2>
<ol>
<li>{@link android.view.Menu}</li>
<li>{@link android.view.MenuItem}</li>
<li>{@link android.view.ContextMenu}</li>
<li>{@link android.view.SubMenu}</li>
</ol>
<h2>See also</h2>
<ol>
<li><a href="{@docRoot}guide/topics/resources/menu-resource.html">Menu Resource</a></li>
</ol>
</div> </div>
</div> </div>
<p>Menus are an important part of any application. They provide familiar interfaces <p>Menus are an important part of an application that provide a familiar interface for the user
that reveal application functions and settings. Android offers an easy programming interface to access application functions and settings. Android offers an easy programming interface
for developers to provide standardized application menus for various situations.</p> for you to provide application menus in your application.</p>
<p>Android offers three fundamental types of application menus:</p> <p>Android provides three types of application menus:</p>
<dl> <dl>
<dt><strong>Options Menu</strong></dt> <dt><strong>Options Menu</strong></dt>
<dd>This is the primary set of menu items for an Activity. It is revealed by pressing <dd>The primary menu for an Activity, which appears when the user presses
the device MENU key. Within the Options Menu are two groups of menu items: the device MENU key. Within the Options Menu are two groups:
<dl style="margin-top:1em"> <dl style="margin-top:1em">
<dt><em>Icon Menu</em></dt> <dt><em>Icon Menu</em></dt>
<dd>This is the collection of items initially visible at the bottom of the screen <dd>The menu items visible at the bottom of the screen
at the press of the MENU key. It supports a maximum of six menu items. at the press of the MENU key. It supports a maximum of six menu items.
These are the only menu items that support icons and the only menu items that <em>do not</em> support These are the only menu items that support icons and the only menu items that <em>do not</em> support
checkboxes or radio buttons.</dd> checkboxes or radio buttons.</dd>
<dt><em>Expanded Menu</em></dt> <dt><em>Expanded Menu</em></dt>
<dd>This is a vertical list of items exposed by the "More" menu item from the Icon Menu. <dd>The vertical list of menu items exposed by the "More" menu item in the Icon Menu.
It exists only when the Icon Menu becomes over-loaded and is comprised of the sixth When the Icon Menu is full, the expanded menu is comprised of the sixth
Option Menu item and the rest.</dd> menu item and the rest.</dd>
</dl> </dl>
</dd> </dd>
<dt><strong>Context Menu</strong></dt> <dt><strong>Context Menu</strong></dt>
<dd>This is a floating list of menu items that may appear when you perform a long-press on a View <dd>A floating list of menu items that appears when the user performs a long-press on a View.
(such as a list item). </dd> </dd>
<dt><strong>Submenu</strong></dt> <dt><strong>Submenu</strong></dt>
<dd>This is a floating list of menu items that is revealed by an item in the Options Menu <dd>A floating list of menu items that the user opens by pressing a menu item in the Options
or a Context Menu. A Submenu item cannot support nested Submenus. </dd> Menu or a context menu. A submenu item cannot support a nested submenu. </dd>
</dl> </dl>
<h2 id="options-menu">Options Menu</h2>
<img align="right" src="{@docRoot}images/options_menu.png" />
<p>The Options Menu is opened by pressing the device MENU key.
When opened, the Icon Menu is displayed, which holds the first six menu items.
If more than six items are added to the Options Menu, then those that can't fit
in the Icon Menu are revealed in the Expanded Menu, via the "More" menu item. The Expanded Menu
is automatically added when there are more than six items.</p>
<p>The Options Menu is where you should include basic application functions <h2 id="xml">Defining Menus</h2>
and any necessary navigation items (e.g., to a home screen or application settings).
You can also add <a href="#submenu">Submenus</a> for organizing topics
and including extra menu functionality.</p>
<p>When this menu is opened for the first time, <p>Instead of instantiating {@link android.view.Menu} objects in your application code, you should
the Android system will call the Activity <code>{@link android.app.Activity#onCreateOptionsMenu(Menu) define a menu and all its items in an XML <a
onCreateOptionsMenu()}</code> callback method. Override this method in your Activity href="{@docRoot}guide/topics/resources/menu-resource.html">menu resource</a>, then inflate the menu
and populate the {@link android.view.Menu} object given to you. You can populate the menu by resource (load it as a programmable object) in your application code. Defining your menus in XML is
inflating a menu resource that was <a href="#xml">defined in XML</a>, or by calling a good practice because it separates your interface design from your application code (the same as
<code>{@link android.view.Menu#add(CharSequence) add()}</code> when you <a href="{@docRoot}guide/topics/ui/declaring-layout.html">define your Activity
for each item you'd like in the menu. This method adds a {@link android.view.MenuItem}, and returns the layout</a>).</p>
newly created object to you. You can use the returned MenuItem to set additional properties like
an icon, a keyboard shortcut, an intent, and other settings for the item.</p>
<p>There are multiple <code>{@link android.view.Menu#add(CharSequence) add()}</code> methods. <p>To define a menu, create an XML file inside your project's <code>res/menu/</code>
Usually, you'll want to use one that accepts an <var>itemId</var> argument. directory and build the menu with the following elements:</p>
This is a unique integer that allows you to identify the item during a callback.</p> <dl>
<dt><code>&lt;menu></code></dt>
<dd>Creates a {@link android.view.Menu}, which is a container for menu items. It must be
the root node and holds one or more of the following elements. You can also nest this element
in an {@code &lt;item&gt;} to create a submenu.</dd>
<dt><code>&lt;item></code></dt>
<dd>Creates a {@link android.view.MenuItem}, which represents a single item in a menu.</dd>
<dt><code>&lt;group></code></dt>
<dd>An optional, invisible container for {@code &lt;item&gt;} elements. It allows you to
categorize menu items so they share properties such as active state and visibility. See <a
href="#groups">Menu groups</a>.</dd>
</dl>
<p>When a menu item is selected from the Options Menu, you will receive a callback to the <p>For example, here is a file in <code>res/menu/</code> named <code>game_menu.xml</code>:</p>
<code>{@link android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()}</code> <pre>
method of your Activity. This callback passes you the &lt;?xml version="1.0" encoding="utf-8"?&gt;
<code>MenuItem</code> that has been selected. You can identify the item by requesting the &lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
<var>itemId</var>, with <code>{@link android.view.MenuItem#getItemId() getItemId()}</code>, &lt;item android:id="@+id/new_game"
which returns the integer that was assigned with the <code>add()</code> method. Once you identify android:icon="@drawable/ic_new_game"
the menu item, you can take the appropriate action.</p> android:title="@string/new_game" /&gt;
&lt;item android:id="@+id/quit"
android:icon="@drawable/ic_quit"
android:title="@string/quit" /&gt;
&lt;/menu&gt;
</pre>
<p>Here's an example of this procedure, inside an Activity, wherein we create an <p>This example defines a menu with two menu items. Each item includes the attributes:</p>
Options Menu and handle item selections:</p> <dl>
<dt>{@code android:id}</dt>
<dd>A resource ID that's unique to the item so that the application can recognize the item when
the user selects it.</dd>
<dt>{@code android:icon}</dt>
<dd>A drawable resource that is the icon visible to the user.</dd>
<dt>{@code android:title}</dt>
<dd>A string resource that is the title visible to the user.</dd>
</dl>
<p>For more about the XML syntax and attributes for a menu resource, see the <a
href="{@docRoot}guide/topics/resources/menu-resource.html">Menu Resource</a> reference.</p>
<h2 id="Inflating">Inflating a Menu Resource</h2>
<p>You can inflate your menu resource (convert the XML resource into a programmable object) using
{@link android.view.MenuInflater#inflate(int,Menu) MenuInflater.inflate()}. For
example, the following code inflates the <code>game_menu.xml</code> file defined above during the
{@link android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()} callback method, to be
used for the Options Menu:</p>
<pre> <pre>
/* Creates the menu items */ &#64;Override
public boolean onCreateOptionsMenu(Menu menu) { public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0, MENU_NEW_GAME, 0, "New Game"); MenuInflater inflater = getMenuInflater();
menu.add(0, MENU_QUIT, 0, "Quit"); inflater.inflate(R.menu.game_menu, menu);
return true; return true;
} }
/* Handles item selections */
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case MENU_NEW_GAME:
newGame();
return true;
case MENU_QUIT:
quit();
return true;
}
return false;
}
</pre> </pre>
<p>The <code>add()</code> method used in this sample takes four arguments: <p>The {@link android.app.Activity#getMenuInflater()} method returns a {@link
<var>groupId</var>, <var>itemId</var>, <var>order</var>, and <var>title</var>. android.view.MenuInflater} for the Activity. With this object, you can call {@link
The <var>groupId</var> allows you to associate this menu item with a group of other items android.view.MenuInflater#inflate(int,Menu) inflate()}, which inflates a menu resource into a
(more about <a href="#groups">Menu groups</a>, below) &mdash; in {@link android.view.Menu} object. In this example, the menu resource defined by
this example, we ignore it. <var>itemId</var> is a unique integer that we give the <code>game_menu.xml</code>
MenuItem so that can identify it in the next callback. <var>order</var> allows us to is inflated into the {@link android.view.Menu} that was passed into {@link
define the display order of the item &mdash; by default, they are displayed by the android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()}. (This callback method for
order in which we add them. <var>title</var> is, of course, the name that goes on the creating an option menu is discussed more in the next section.)</p>
menu item (this can also be a
<a href="{@docRoot}guide/topics/resources/available-resources.html#stringresources">string resource</a>,
and we recommend you do it that way for easier localization).</p>
<p class="note"><strong>Tip:</strong>
If you have several menu items that can be grouped together with a title,
consider organizing them into a <a href="#submenu">Submenu</a>.</p>
<h3>Adding icons</h3>
<p>Icons can also be added to items that appears in the Icon Menu with <h2 id="options-menu">Creating an Options Menu</h2>
<code>{@link android.view.MenuItem#setIcon(Drawable) setIcon()}</code>. For example:</p>
<div class="figure" style="width:200px">
<img src="{@docRoot}images/options_menu.png" height="300" alt="" />
<p class="img-caption"><strong>Figure 1.</strong> Screenshot of an Options Menu.</p>
</div>
<p>The Options Menu is where you should include basic application functions
and necessary navigation items (for example, a button
to open application settings). The user
can open the Options Menu with the device MENU key.
Figure 1 shows a screenshot of an Options Menu.</p>
<p>When opened, the first visible portion of the Options Menu is called the Icon Menu. It
holds the first six menu items.
If you add more than six items to the Options Menu, Android places the sixth item and those after it
into the Expanded Menu, which the user can open with the "More" menu item.</p>
<p>When the user opens the Options Menu for the first time, Android calls your Activity's
{@link android.app.Activity#onCreateOptionsMenu(Menu)
onCreateOptionsMenu()} method. Override this method in your Activity
and populate the {@link android.view.Menu} that is passed into the method. Populate the
{@link android.view.Menu} by inflating a menu resource as described in <a
href="#Inflating">Inflating a Menu Resource</a>. (You can
also populate the menu in code, using {@link android.view.Menu#add(int,int,int,int)
add()} to add menu items.)</p>
<p>When the user selects a menu item from the Options Menu, the system calls your Activity's
{@link android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()}
method. This method passes the
{@link android.view.MenuItem} that the user selected. You can identify the menu item by calling
{@link android.view.MenuItem#getItemId()}, which returns the unique ID for the menu
item (defined by the {@code android:id} attribute in the menu resource or with an integer passed
to the {@link android.view.Menu#add(int,int,int,int) add()} method). You can match this ID
against known menu items and perform the appropriate action.</p>
<p>For example:</p>
<pre> <pre>
menu.add(0, MENU_QUIT, 0, "Quit") &#64;Override
.setIcon(R.drawable.menu_quit_icon);</pre> public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.new_game:
newGame();
return true;
case R.id.quit:
quit();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
</pre>
<h3>Modifying the menu</h3> <p>In this example, {@link android.view.MenuItem#getItemId()} queries the ID for the selected menu
<p>If you want to sometimes re-write the Options Menu as it is opened, override the item and the switch statement compares the ID against the resource IDs that were assigned to menu
<code>{@link android.app.Activity#onPrepareOptionsMenu(Menu) onPrepareOptionsMenu()}</code> method, which is items in the XML resource. When a switch case successfully handles the item, it
called each time the menu is opened. This will pass you the Menu object, just like the returns "true" to indicate that the item selection was handled. Otherwise, the default statement
<code>onCreateOptionsMenu()</code> callback. This is useful if you'd like to add or remove passes the menu item to the super class in
menu options depending on the current state of an application or game.</p> case it can handle the item selected. (If you've directly extended the {@link android.app.Activity}
class, then the super class returns "false", but it's a good practice to
pass unhandled menu items to the super class instead of directly returning "false".)</p>
<p class="note"><strong>Tip:</strong> If your application contains multiple activities and
some of them provide the same Options Menu, consider creating
an Activity that implements nothing except the {@link android.app.Activity#onCreateOptionsMenu(Menu)
onCreateOptionsMenu()} and {@link android.app.Activity#onOptionsItemSelected(MenuItem)
onOptionsItemSelected()} methods. Then extend this class for each Activity that should share the
same Options Menu. This way, you have to manage only one set of code for handling menu
actions and each decendent class inherits the menu behaviors.<br/><br/>
If you want to add menu items to one of your decendent activities,
override {@link android.app.Activity#onCreateOptionsMenu(Menu)
onCreateOptionsMenu()} in that Activity. Call {@code super.onCreateOptionsMenu(menu)} so the
original menu items are created, then add new menu items with {@link
android.view.Menu#add(int,int,int,int) menu.add()}. You can also override the super class's
behavior for individual menu items.</p>
<h3 id="ChangingTheMenu">Changing the menu when it opens</h3>
<p>The {@link android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()} method is
called only the first time the Options Menu is opened. The system keeps and re-uses the {@link
android.view.Menu} you define in this method until your Activity is destroyed. If you want to change
the Options Menu each time it opens, you must override the
{@link android.app.Activity#onPrepareOptionsMenu(Menu) onPrepareOptionsMenu()} method. This passes
you the {@link android.view.Menu} object as it currently exists. This is useful if you'd like to
remove, add, disable, or enable menu items depending on the current state of your application.</p>
<p class="note"><strong>Note:</strong> <p class="note"><strong>Note:</strong>
When changing items in the menu, it's bad practice to do so based on the currently selected item. You should never change items in the Options Menu based on the {@link android.view.View} currently
Keep in mind that, when in touch mode, there will not be a selected (or focused) item. Instead, you in focus. When in touch mode (when the user is not using a trackball or d-pad), Views
should use a <a href="#context-menu">Context Menu</a> for such behaviors, when you want to provide cannot take focus, so you should never use focus as the basis for modifying
functionality based on a particular item in the UI.</p> items in the Options Menu. If you want to provide menu items that are context-sensitive to a {@link
android.view.View}, use a <a href="#context-menu">Context Menu</a>.</p>
<h2 id="context-menu">Context Menu</h2>
<p>The Android context menu is similar, in concept, to the menu revealed with a "right-click" on a PC.
When a view is registered to a context menu,
performing a "long-press" (press and hold for about two seconds) on the object
will reveal a floating menu that provides functions relating to that item.
Context menus can be registered to any View object,
however, they are most often used for items in a
{@link android.widget.ListView}, which helpfully indicates the presence of the context menu
by transforming the background color of the ListView item when pressed.
(The items in the phone's contact list offer an example of this feature.)
</p>
<p class="note"><strong>Note:</strong> Context menu items do not support icons or shortcut keys.</p> <h2 id="context-menu">Creating a Context Menu</h2>
<p>To create a context menu, you must override the Activity's context menu callback methods: <p>A context menu is conceptually similar to the menu displayed when the user performs a
<code>{@link android.app.Activity#onCreateContextMenu(ContextMenu,View,ContextMenuInfo) onCreateContextMenu()}</code> and "right-click" on a PC. You should use a context menu to provide the user access to
<code>{@link android.app.Activity#onContextItemSelected(MenuItem) onContextItemSelected()}</code>. actions that pertain to a specific item in the user interface. On Android, a context menu is
Inside the <code>onCreateContextMenu()</code> callback method, you can add menu items using one of the displayed when the user performs a "long press" (press and hold) on an item.</p>
<code>{@link android.view.Menu#add(CharSequence) add()}</code> methods, or by
inflating a menu resource that was <a href="#xml">defined in XML</a>.
Then, register a {@link android.view.ContextMenu} for the View, with
<code>{@link android.app.Activity#registerForContextMenu(View) registerForContextMenu()}</code>.</p>
<p>For example, here is some code that can be used with the <p>You can create a context menu for any View, though context menus are most often used for items in
<a href="{@docRoot}resources/tutorials/notepad/index.html">Notepad application</a> a {@link android.widget.ListView}. When the user performs a long-press on an item in a ListView and
to add a context menu for each note in the list:</p> the list is registered to provide a context menu, the list item signals to the user that a context
menu is available by animating its background color&mdash;it transitions from
orange to white before opening the context menu. (The Contacts application demonstrates this
feature.)</p>
<div class="sidebox-wrapper">
<div class="sidebox">
<h3>Register a ListView</h3>
<p>If your Activity uses a {@link android.widget.ListView} and
you want all list items to provide a context menu, register all items for a context
menu by passing the {@link android.widget.ListView} to {@link
android.app.Activity#registerForContextMenu(View) registerForContextMenu()}. For
example, if you're using a {@link android.app.ListActivity}, register all list items like this:</p>
<p><code>registerForContextMenu({@link android.app.ListActivity#getListView()});</code></p>
</div>
</div>
<p>In order for a View to provide a context menu, you must "register" the view for a context
menu. Call {@link android.app.Activity#registerForContextMenu(View) registerForContextMenu()} and
pass it the {@link android.view.View} you want to give a context menu. When this View then
receives a long-press, it displays a context menu.</p>
<p>To define the context menu's appearance and behavior, override your Activity's context menu
callback methods, {@link android.app.Activity#onCreateContextMenu(ContextMenu,View,ContextMenuInfo)
onCreateContextMenu()} and
{@link android.app.Activity#onContextItemSelected(MenuItem) onContextItemSelected()}.</p>
<p>For example, here's an {@link
android.app.Activity#onCreateContextMenu(ContextMenu,View,ContextMenuInfo)
onCreateContextMenu()} that uses the {@code context_menu.xml} menu resource:</p>
<pre> <pre>
&#64;Override
public void onCreateContextMenu(ContextMenu menu, View v, public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) { ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo); super.onCreateContextMenu(menu, v, menuInfo);
menu.add(0, EDIT_ID, 0, "Edit"); MenuInflater inflater = getMenuInflater();
menu.add(0, DELETE_ID, 0, "Delete"); inflater.inflate(R.menu.context_menu, menu);
} }
</pre>
<p>{@link android.view.MenuInflater} is used to inflate the context menu from a <a
href="{@docRoot}guide/topics/resources/menu-resource.html">menu resource</a>. (You can also use
{@link android.view.Menu#add(int,int,int,int) add()} to add menu items.) The callback method
parameters include the {@link android.view.View}
that the user selected and a {@link android.view.ContextMenu.ContextMenuInfo} object that provides
additional information about the item selected. You might use these parameters to determine
which context menu should be created, but in this example, all context menus for the Activity are
the same.</p>
<p>Then when the user selects an item from the context menu, the system calls {@link
android.app.Activity#onContextItemSelected(MenuItem) onContextItemSelected()}. Here is an example
of how you can handle selected items:</p>
<pre>
&#64;Override
public boolean onContextItemSelected(MenuItem item) { public boolean onContextItemSelected(MenuItem item) {
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo(); AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
switch (item.getItemId()) { switch (item.getItemId()) {
case EDIT_ID: case R.id.edit:
editNote(info.id); editNote(info.id);
return true; return true;
case DELETE_ID: case R.id.delete:
deleteNote(info.id); deleteNote(info.id);
return true; return true;
default: default:
@@ -205,285 +331,276 @@ public boolean onContextItemSelected(MenuItem item) {
} }
</pre> </pre>
<p>In <code>onCreateContextMenu()</code>, we are given not only the ContextMenu to <p>The structure of this code is similar to the example for <a href="#options-menu">Creating an
which we will add {@link android.view.MenuItem}s, but also the {@link android.view.View} Options Menu</a>, in which {@link android.view.MenuItem#getItemId()} queries the ID for the selected
that was selected and a {@link android.view.ContextMenu.ContextMenuInfo ContextMenuInfo} object, menu item and a switch statement matches the item to the IDs that are defined in the menu resource.
which provides additional information about the object that was selected. And like the options menu example, the default statement calls the super class in case it
In this example, nothing special is done in <code>onCreateContextMenu()</code> &mdash; just can handle menu items not handled here, if necessary.</p>
a couple items are added as usual. In the <code>onContextItemSelected()</code>
callback, we request the {@link android.widget.AdapterView.AdapterContextMenuInfo AdapterContextMenuInfo}
from the {@code MenuItem}, which provides information about the currently selected item.
All we need from
this is the list ID for the selected item, so whether editing a note or deleting it,
we find the ID with the {@code AdapterContextMenuInfo.info} field of the object. This ID
is passed to the <code>editNote()</code> and <code>deleteNote()</code> methods to perform
the respective action.</p>
<p>Now, to register this context menu for all the items in a {@link android.widget.ListView}, <p>In this example, the selected item is an item from a {@link android.widget.ListView}. To
we pass the entire {@code ListView} to the perform an action on the selected item, the application needs to know the list
<code>{@link android.app.Activity#registerForContextMenu(View)}</code> method:</p> ID for the selected item (it's position in the ListView). To get the ID, the application calls
{@link android.view.MenuItem#getMenuInfo()}, which returns a {@link
android.widget.AdapterView.AdapterContextMenuInfo} object that includes the list ID for the
selected item in the {@link android.widget.AdapterView.AdapterContextMenuInfo#id id} field. The
local methods <code>editNote()</code> and <code>deleteNote()</code> methods accept this list ID to
perform an action on the data specified by the list ID.</p>
<pre>registerForContextMenu(getListView());</pre> <p class="note"><strong>Note:</strong> Items in a context menu do not support icons or shortcut
<p>Remember, you can pass any View object to register a context menu. Here, keys.</p>
<code>{@link android.app.ListActivity#getListView()}</code> returns the ListView
object used in the Notepad application's {@link android.app.ListActivity}. As such, each item
in the list is registered to this context menu.</p>
<h2 id="submenu">Submenus</h2> <h2 id="submenu">Creating Submenus</h2>
<p>A sub menu can be added within any menu, except another sub menu.
These are very useful when your application has a lot of functions that may be
organized in topics, like the items in a PC application's menu bar (File, Edit, View, etc.).</p>
<p>A sub menu is created by adding it to an existing {@link android.view.Menu} <p>A submenu is a menu that the user can open by selecting an item in another menu. You can add a
with <code>{@link android.view.Menu#addSubMenu(CharSequence) addSubMenu()}</code>. submenu to any menu (except a submenu). Submenus are useful when your application has a lot of
This returns a {@link android.view.SubMenu} object (an extension of {@link android.view.Menu}). functions that can be organized into topics, like items in a PC application's menu bar (File, Edit,
You can then add additional items to this menu, with the normal routine, using View, etc.).</p>
the <code>{@link android.view.Menu#add(CharSequence) add()}</code> methods. For example:</p>
<p>When creating your <a href="{@docRoot}guide/topics/resources/menu-resource.html">menu
resource</a>, you can create a submenu by adding a {@code &lt;menu&gt;} element as the child of an
{@code &lt;item&gt;}. For example:</p>
<pre> <pre>
public boolean onCreateOptionsMenu(Menu menu) { &lt;?xml version="1.0" encoding="utf-8"?&gt;
boolean result = super.onCreateOptionsMenu(menu); &lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
&lt;item android:id="@+id/file"
SubMenu fileMenu = menu.addSubMenu("File"); android:icon="@drawable/file"
SubMenu editMenu = menu.addSubMenu("Edit"); android:title="@string/file" &gt;
fileMenu.add("new"); &lt;!-- "file" submenu --&gt;
fileMenu.add("open"); &lt;menu"&gt;
fileMenu.add("save"); &lt;item android:id="@+id/new"
editMenu.add("undo"); android:title="@string/new" /&gt;
editMenu.add("redo"); &lt;item android:id="@+id/open"
android:title="@string/open" /&gt;
return result; &lt;/menu&gt;
} &lt;/item&gt;
</pre> &lt;/menu&gt;
<p>Callbacks for items selected in a sub menu are made to the parent menu's callback method.
For the example above, selections in the sub menu will be handled by the
<code>onOptionsItemSelected()</code> callback.</p>
<p>You can also add Submenus when you <a href="#xml">define the parent menu in XML</a>.</p>
<h2 id="xml">Define Menus in XML</h2>
<p>Just like Android UI layouts, you can define application menus in XML, then inflate them
in your menu's <code>onCreate...()</code> callback method. This makes your application code cleaner and
separates more interface design into XML, which is easier to visualize.</p>
<p>To start, create a new folder in your project <code>res/</code> directory called <code>menu</code>.
This is where you should keep all XML files that define your application menus.</p>
<p>In a menu XML layout, there are
three valid elements: <code>&lt;menu></code>, <code>&lt;group></code> and <code>&lt;item></code>. The
<code>item</code> and <code>group</code> elements must be children of a <code>menu</code>, but <code>item</code>
elements may also be the children of a <code>group</code>, and another <code>menu</code> element may be the child
of an <code>item</code> (to create a Submenu). Of course, the root node of any file
must be a <code>menu</code> element.</p>
<p>As an example, we'll define the same menu created in the <a href="#options-menu">Options Menu</a> section,
above. We start with an XML file named <code>options_menu.xml</code> inside the <code>res/menu/</code> folder:</p>
<pre>
&lt;menu xmlns:android="http://schemas.android.com/apk/res/android">
&lt;item android:id="@+id/new_game"
android:title="New Game" />
&lt;item android:id="@+id/quit"
android:title="Quit" />
&lt;/menu>
</pre> </pre>
<p>Then, in the <code>onCreateOptionsMenu()</code> method, we inflate this resource using <p>When the user selects an item from a submenu, the parent menu's respective on-item-selected
<code>{@link android.view.MenuInflater#inflate(int,Menu) MenuInflater.inflate()}</code>:</p> callback method receives the event. For instance, if the above menu is applied as an Options Menu,
<pre> then the {@link android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()} method
public boolean onCreateOptionsMenu(Menu menu) { is called when a submenu item is selected.</p>
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.options_menu, menu);
return true;
}
</pre>
<p>The <code>{@link android.app.Activity#getMenuInflater()}</code> method returns the {@link android.view.MenuInflater} <p>You can also use {@link android.view.Menu#addSubMenu(int,int,int,int) addSubMenu()} to
for our activity's context. We then call <code>{@link android.view.MenuInflater#inflate(int,Menu) inflate()}</code>, dynamically add a {@link android.view.SubMenu} to an existing {@link android.view.Menu}. This
passing it a pointer to our menu resource and the Menu object given by the callback.</code></p> returns the new {@link android.view.SubMenu} object, to which you can add
submenu items, using {@link android.view.Menu#add(int,int,int,int) add()}</p>
<p>While this small sample may seem like more effort, compared to creating the menu items in the
<code>onCreateOptionsMenu()</code> method, this will save a lot of trouble when dealing with more items
and it keeps your application code clean.</p>
<p>You can define <a href="#groups">menu groups</a> by wrapping <code>item</code> elements in a <code>group</code>
element, and create Submenus by nesting another <code>menu</code> inside an <code>item</code>.
Each element also supports all the necessary attributes to control features like shortcut keys,
checkboxes, icons, and more. To learn about these attributes and more about the XML syntax, see the Menus
topic in the <a href="{@docRoot}guide/topics/resources/available-resources.html#menus">Available
Resource Types</a> document.</p>
<h2 id="features">Menu Features</h2> <h2 id="features">Other Menu Features</h2>
<p>Here are some other features that can be applied to most menu items.</p>
<p>Here are some other features that you can apply to most menu items.</p>
<h3 id="groups">Menu groups</h3> <h3 id="groups">Menu groups</h3>
<p>When adding new items to a menu, you can optionally include each item in a group.
A menu group is a collection of menu items that can share certain traits, like
whether they are visible, enabled, or checkable.</p>
<p>A group is defined by an integer (or a resource id, in XML). A menu item is added to the group when it is <p>A menu group is a collection of menu items that share certain traits. With a group, you
added to the menu, using one of the <code>add()</code> methods that accepts a <var>groupId</var> can:</p>
as an argument, such as <code>{@link android.view.Menu#add(int,int,int,int)}</code>.</p> <ul>
<li>Show or hide all items with {@link android.view.Menu#setGroupVisible(int,boolean)
setGroupVisible()}</li>
<li>Enable or disable all items with {@link android.view.Menu#setGroupEnabled(int,boolean)
setGroupEnabled()}</li>
<li>Specify whether all items are checkable with {@link
android.view.Menu#setGroupCheckable(int,boolean,boolean) setGroupCheckable()}</li>
</ul>
<p>You can create a group by nesting {@code &lt;item&gt;} elements inside a {@code &lt;group&gt;}
element in your menu resource or by specifying a group ID with the the {@link
android.view.Menu#add(int,int,int,int) add()} method.</p>
<p>Here's an example menu resource that includes a group:</p>
<pre>
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
&lt;item android:id="@+id/item1"
android:icon="@drawable/item1"
android:title="@string/item1" /&gt;
&lt;!-- menu group --&gt;
&lt;group android:id="@+id/group1"&gt;
&lt;item android:id="@+id/groupItem1"
android:title="@string/groupItem1" /&gt;
&lt;item android:id="@+id/groupItem2"
android:title="@string/groupItem2" /&gt;
&lt;/group&gt;
&lt;/menu&gt;
</pre>
<p>The items that are in the group appear the same as the first item that is not in a
group&mdash;all three items in the menu are siblings. However, you can modify the traits of the two
items in the group by referencing the group ID and using the methods listed above.</p>
<p>You can show or hide the entire group with
<code>{@link android.view.Menu#setGroupVisible(int,boolean) setGroupVisible()}</code>;
enable or disable the group with
<code>{@link android.view.Menu#setGroupEnabled(int,boolean) setGroupEnabled()}</code>;
and set whether the items can be checkable with
<code>{@link android.view.Menu#setGroupCheckable(int,boolean,boolean) setGroupCheckable()}</code>.
</p>
<h3 id="checkable">Checkable menu items</h3> <h3 id="checkable">Checkable menu items</h3>
<img align="right" src="{@docRoot}images/radio_buttons.png" alt="" />
<p>Any menu item can be used as an interface for turning options on and off. This can
be indicated with a checkbox for stand-alone options, or radio buttons for groups of
mutually exclusive options (see the screenshot, to the right).</p>
<p class="note"><strong>Note:</strong> Menu items in the Icon Menu cannot <div class="figure" style="width:200px">
<img src="{@docRoot}images/radio_buttons.png" height="300" alt="" />
<p class="img-caption"><strong>Figure 2.</strong> Screenshot of checkable menu items</p>
</div>
<p>A menu can be useful as an interface for turning options on and off, using a checkbox for
stand-alone options, or radio buttons for groups of
mutually exclusive options. Figure 2 shows a submenu with items that are checkable with radio
buttons.</p>
<p class="note"><strong>Note:</strong> Menu items in the Icon Menu (from the Options Menu) cannot
display a checkbox or radio button. If you choose to make items in the Icon Menu checkable, display a checkbox or radio button. If you choose to make items in the Icon Menu checkable,
then you must personally indicate the state by swapping the icon and/or text you must manually indicate the checked state by swapping the icon and/or text
each time the state changes between on and off.</p> each time the state changes.</p>
<p>You can define the checkable behavior for individual menu items using the {@code
android:checkable} attribute in the {@code &lt;item&gt;} element, or for an entire group with
the {@code android:checkableBehavior} attribute in the {@code &lt;group&gt;} element. For
example, all items in this menu group are checkable with a radio button:</p>
<p>To make a single item checkable, use the <code>{@link android.view.MenuItem#setCheckable(boolean)
setCheckable()}</code> method, like so:</p>
<pre> <pre>
menu.add(0, VIBRATE_SETTING_ID, 0, "Vibrate") &lt;?xml version="1.0" encoding="utf-8"?&gt;
.setCheckable(true); &lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
&lt;group android:checkableBehavior="single"&gt;
&lt;item android:id="@+id/red"
android:title="@string/red" /&gt;
&lt;item android:id="@+id/blue"
android:title="@string/blue" /&gt;
&lt;/group&gt;
&lt;/menu&gt;
</pre> </pre>
<p>This will display a checkbox with the menu item (unless it's in the Icon Menu). When the item
is selected, the <code>onOptionsItemSelected()</code> callback is called as usual. It is here that <p>The {@code android:checkableBehavior} attribute accepts either:
you must set the state of the checkbox. You can query the current state of the item with <dl>
<code>{@link android.view.MenuItem#isChecked()}</code> and set the checked state with <dt>{@code single}</dt>
<code>{@link android.view.MenuItem#setChecked(boolean) setChecked()}</code>. <dd>Only one item from the group can be checked (radio buttons)</dd>
Here's what this looks like inside the <dt>{@code all}</dt>
<code>onOptionsItemSelected()</code> callback:</p> <dd>All items can be checked (checkboxes)</dd>
<dt>{@code none}</dt>
<dd>No items are checkable</dd>
</dl>
<p>You can apply a default checked state to an item using the {@code android:checked} attribute in
the {@code &lt;item&gt;} element and change it in code with the {@link
android.view.MenuItem#setChecked(boolean) setChecked()} method.</p>
<p>When a checkable item is selected, the system calls your respective item-selected callback method
(such as {@link android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()}). It
is here that you must set the state of the checkbox, because a checkbox or radio button does not
change its state automatically. You can query the current state of the item (as it was before the
user selected it) with {@link android.view.MenuItem#isChecked()} and then set the checked state with
{@link android.view.MenuItem#setChecked(boolean) setChecked()}. For example:</p>
<pre> <pre>
&#64;Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) { switch (item.getItemId()) {
case VIBRATE_SETTING_ID: case R.id.vibrate:
case R.id.dont_vibrate:
if (item.isChecked()) item.setChecked(false); if (item.isChecked()) item.setChecked(false);
else item.setChecked(true); else item.setChecked(true);
return true; return true;
... default:
return super.onOptionsItemSelected(item);
}
} }
</pre> </pre>
<p>To make a group of mutually exclusive radio button items, simply <p>If you don't set the checked state this way, then the visible state of the item (the checkbox or
assign the same group ID to each menu item radio button) will not
and call <code>{@link android.view.Menu#setGroupCheckable(int,boolean,boolean) change when the user selects it. When you do set the state, the Activity preserves the checked state
setGroupCheckable()}</code>. In this case, you don't need to call <code>setCheckable()</code> of the item so that when the user opens the menu later, the checked state that you
on each menu items, because the group as a whole is set checkable. Here's an example of set is visible.</p>
two mutually exclusive options in a Submenu:</p>
<pre>
SubMenu subMenu = menu.addSubMenu("Color");
subMenu.add(COLOR_MENU_GROUP, COLOR_RED_ID, 0, "Red");
subMenu.add(COLOR_MENU_GROUP, COLOR_BLUE_ID, 0, "Blue");
subMenu.setGroupCheckable(COLOR_MENU_GROUP, true, true);
</pre>
<p>In the <code>setGroupCheckable()</code> method, the first argument is the group ID
that we want to set checkable. The second argument is whether we want the group items
to be checkable. The last one is whether we want each item to be exclusively checkable
(if we set this <em>false</em>, then all the items will be checkboxes instead of radio buttons).
When the group is set to be exclusive (radio buttons), each time a new item is selected,
all other are automatically de-selected.</p>
<p>
<p class="note"><strong>Note:</strong> <p class="note"><strong>Note:</strong>
Checkable menu items are intended to be used only on a per-session basis and not saved to the device Checkable menu items are intended to be used only on a per-session basis and not saved after the
(e.g., the <em>Map mode</em> setting in the Maps application is not saved &mdash; screenshot above). application is destroyed. If you have application settings that you would like to save for the user,
If there are application settings that you would like to save for the user, you should store the data using <a
then you should store the data using <a href="#{@docRoot}guide/topics/data/data-storage.html#pref">Preferences</a>, href="#{@docRoot}guide/topics/data/data-storage.html#pref">Shared Preferences</a>.</p>
and manage them with a {@link android.preference.PreferenceActivity}.</p>
<h3 id="shortcuts">Shortcut keys</h3> <h3 id="shortcuts">Shortcut keys</h3>
<p>Quick access shortcut keys using letters and/or numbers can be added to menu items with
<code>setAlphabeticShortcut(char)</code> (to set char shortcut), <code>setNumericShortcut(int)</code>
(to set numeric shortcut),
or <code>setShortcut(char,int)</code> (to set both)</code>. Case is <em>not</em> sensitive.
For example:</p> <p>You can add quick-access shortcut keys using letters and/or numbers to menu items with the
<pre> {@code android:alphabeticShortcut} and {@code android:numericShortcut} attributes in the {@code
menu.add(0, MENU_QUIT, 0, "Quit") &lt;item&gt;} element. You can also use the methods {@link
.setAlphabeticShortcut('q'); android.view.MenuItem#setAlphabeticShortcut(char)} and {@link
</pre> android.view.MenuItem#setNumericShortcut(char)}. Shortcut keys are <em>not</em>
<p>Now, when the menu is open (or while holding the MENU key), pressing the "q" key will case sensitive.</p>
select this item.</p>
<p>This shortcut key will be displayed as a tip in the menu item, below the menu item name <p>For example, if you apply the "s" character as an alphabetic shortcut to a "save" menu item, then
(except for items in the Icon Menu).</p> when the menu is open (or while the user holds the MENU key) and the user presses the "s" key,
<p class="note"><strong>Note:</strong> Shortcuts cannot be added to items in a Context Menu.</p> the "save" menu item is selected.</p>
<p>This shortcut key is displayed as a tip in the menu item, below the menu item name
(except for items in the Icon Menu, which are displayed only if the user holds the MENU
key).</p>
<p class="note"><strong>Note:</strong> Shortcut keys for menu items only work on devices with a
hardware keyboard. Shortcuts cannot be added to items in a Context Menu.</p>
<h3 id="intents">Menu item intents</h3> <h3 id="intents">Intents for menu items</h3>
<p>If you've read the <a href="{@docRoot}guide/topics/fundamentals.html">Application
Fundamentals</a>, then you're at least a little familiar
with Android Intents. These allow applications to bind with each other, share information,
and perform user tasks cooperatively. Just like your application might fire an Intent to launch a web browser,
an email client, or another Activity in your application,
you can perform such actions from within a menu.
There are two ways to do this: define an Intent and assign it to a single menu item, or
define an Intent and allow Android to search the device for activities and dynamically add a
menu item for each one that meets the Intent criteria.</p>
<p>For more information on creating Intents and providing your application's services to other applications, <p>Sometimes you'll want a menu item to launch an Activity using an Intent (whether it's an
read the <a href="/guide/topics/intents/intents-filters.html">Intents Actvitity in your application or another application). When you know the Intent you want to use and
and Intent Filters</a> document.</p> have a specific menu item that should initiate the Intent, you can execute the Intent with {@link
android.app.Activity#startActivity(Intent) startActivity()} during the appropriate on-item-selected
callback method (such as the {@link android.app.Activity#onOptionsItemSelected(MenuItem)
onOptionsItemSelected()} callback).</p>
<h4>Set an intent for a single menu item</h4> <p>However, if you are not certain that the user's device
<p>If you want to offer a specific menu item that launches a new Activity, then you contains an application that handles the Intent, then adding a menu item that executes the
can specifically define an Intent for the menu item with the Intent can result in a non-functioning menu item, because the Intent might not resolve to an
<code>{@link android.view.MenuItem#setIntent(Intent) Activity that accepts it. To solve this, Android lets you dynamically add menu items to your menu
setIntent()}</code> method.</p> when Android finds activities on the device that handle your Intent.</p>
<p>For example, inside the <code>{@link android.app.Activity#onCreateOptionsMenu(Menu) <p>If you're not familiar with creating Intents, read the <a
onCreateOptionsMenu()}</code> method, you can define a new menu item with an Intent like this:</p> href="/guide/topics/intents/intents-filters.html">Intents and Intent Filters</a>.</p>
<pre>
MenuItem menuItem = menu.add(0, PHOTO_PICKER_ID, 0, "Select Photo");
menuItem.setIntent(new Intent(this, PhotoPicker.class));
</pre>
<p>Android will automatically launch the Activity when the item is selected.</p>
<p class="note"><strong>Note:</strong> This will not return a result to your Activity.
If you wish to be returned a result, then do not use <code>setIntent()</code>.
Instead, handle the selection as usual in the <code>onOptionsMenuItemSelected()</code>
or <code>onContextMenuItemSelected()</code> callback and call
<code>{@link android.app.Activity#startActivityForResult(Intent,int) startActivityForResult()}</code>.
</p>
<h4>Dynamically add intents</h4> <h4>Dynamically adding Intents</h4>
<p>If there are potentially multiple activities that are relevant to your current <p>When you don't know if the user's device has an application that handles a specific Intent,
Activity or selected item, then the application can dynamically add menu items that execute other you can define the Intent and let Android search the device for activities that accept the Intent.
services.</p> When it finds activies that handle the Intent, it adds a menu item for
<p>During menu creation, define an Intent with the category <var>Intent.ALTERNATIVE_CATEGORY</var> and/or each one to your menu and attaches the appropriate Intent to open the Activity when the user
<var>Intent.SELECTED_ALTERNATIVE</var>, the MIME type currently selected (if any), and any other selects it.</p>
requirements, the same way as you would satisfy an intent filter to open a new
Activity. Then call <p>To add menu items based on available activities that accept an Intent:</p>
<code>{@link android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[]) <ol>
addIntentOptions()}</code> to have Android search for any services meeting those requirements <li>Define an
and add them to the menu for you. If there are no applications installed Intent with the category {@link android.content.Intent#CATEGORY_ALTERNATIVE} and/or
that satisfy the Intent, then no additional menu items are added.</p> {@link android.content.Intent#CATEGORY_SELECTED_ALTERNATIVE}, plus any other requirements.</li>
<li>Call {@link
android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[])
Menu.addIntentOptions()}. Android then searches for any applications that can perform the Intent
and adds them to your menu.</li>
</ol>
<p>If there are no applications installed
that satisfy the Intent, then no menu items are added.</p>
<p class="note"><strong>Note:</strong> <p class="note"><strong>Note:</strong>
<var>SELECTED_ALTERNATIVE</var> is used to handle the currently selected element on the {@link android.content.Intent#CATEGORY_SELECTED_ALTERNATIVE} is used to handle the currently
screen. So, it should only be used when creating a Menu in <code>onCreateContextMenu()</code> or selected element on the screen. So, it should only be used when creating a Menu in {@link
<code>onPrepareOptionsMenu()</code>, which is called every time the Options Menu is opened.</p> android.app.Activity#onCreateContextMenu(ContextMenu,View,ContextMenuInfo)
onCreateContextMenu()}.</p>
<p>Here's an example demonstrating how an application would search for <p>For example:</p>
additional services to display on its menu.</p>
<pre> <pre>
&#64;Override
public boolean onCreateOptionsMenu(Menu menu){ public boolean onCreateOptionsMenu(Menu menu){
super.onCreateOptionsMenu(menu); super.onCreateOptionsMenu(menu);
// Create an Intent that describes the requirements to fulfill, to be included // Create an Intent that describes the requirements to fulfill, to be included
// in our menu. The offering app must include a category value of Intent.CATEGORY_ALTERNATIVE. // in our menu. The offering app must include a category value of Intent.CATEGORY_ALTERNATIVE.
Intent intent = new Intent(null, getIntent().getData()); Intent intent = new Intent(null, dataUri);
intent.addCategory(Intent.CATEGORY_ALTERNATIVE); intent.addCategory(Intent.CATEGORY_ALTERNATIVE);
// Search for, and populate the menu with, acceptable offering applications. // Search and populate the menu with acceptable offering applications.
menu.addIntentOptions( menu.addIntentOptions(
thisClass.INTENT_OPTIONS, // Menu group R.id.intent_group, // Menu group to which new items will be added
0, // Unique item ID (none) 0, // Unique item ID (none)
0, // Order for the items (none) 0, // Order for the items (none)
this.getComponentName(), // The current Activity name this.getComponentName(), // The current Activity name
@@ -495,17 +612,27 @@ public boolean onCreateOptionsMenu(Menu menu){
return true; return true;
}</pre> }</pre>
<p>For each Activity found that provides an Intent Filter matching the Intent defined, a menu <p>For each Activity found that provides an Intent filter matching the Intent defined, a menu
item will be added, using the <var>android:label</var> value of the intent filter as the text item is added, using the value in the Intent filter's <code>android:label</code> as the
for the menu item. menu item title and the application icon as the menu item icon. The
The <code>{@link android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[]) addIntentOptions()}</code> method will also return the number of menu items added.</p> {@link android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[])
<p>Also be aware that, when <code>addIntentOptions()</code> is called, it will override any and all addIntentOptions()} method returns the number of menu items added.</p>
menu items in the menu group specified in the first argument.</p>
<p>If you wish to offer the services of your Activity to other application menus, then you <p class="note"><strong>Note:</strong> When you call {@link
only need to define an intent filter as usual. Just be sure to include the <var>ALTERNATIVE</var> and/or android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[])
<var>SELECTED_ALTERNATIVE</var> values in the <var>name</var> attribute of addIntentOptions()}, it overrides any and all menu items by the menu group specified in the first
a <code>&lt;category></code> element in the intent filter. For example:</p> argument.</p>
<h4>Allowing your Activity to be added to menus</h4>
<p>You can also offer the services of your Activity to other applications, so your
application can be included in the menu of others (reverse the roles described above).</p>
<p>To be included in other application menus, you need to define an Intent
filter as usual, but be sure to include the {@link android.content.Intent#CATEGORY_ALTERNATIVE}
and/or {@link android.content.Intent#CATEGORY_SELECTED_ALTERNATIVE} values for the Intent filter
category. For example:</p>
<pre> <pre>
&lt;intent-filter label="Resize Image"> &lt;intent-filter label="Resize Image">
... ...
@@ -514,9 +641,10 @@ a <code>&lt;category></code> element in the intent filter. For example:</p>
... ...
&lt;/intent-filter> &lt;/intent-filter>
</pre> </pre>
<p>read more about writing intent filters in the
<p>Read more about writing Intent filters in the
<a href="/guide/topics/intents/intents-filters.html">Intents and Intent Filters</a> document.</p> <a href="/guide/topics/intents/intents-filters.html">Intents and Intent Filters</a> document.</p>
<p>For a sample application using this technique, see the <p>For a sample application using this technique, see the
<a href="{@docRoot}resources/samples/NotePad/index.html">Note Pad</a> <a href="{@docRoot}resources/samples/NotePad/src/com/example/android/notepad/NoteEditor.html">Note
sample code.</p> Pad</a> sample code.</p>