Used to display the options of a application on android devices, this can be at the bottom of the application when the menu-button is pressed or in the overflow-menu of the actionbar.
Introduction
Menus are a common user interface component in many types of applications. To provide a familiar and consistent user experience, you should use the Menu APIs to present user actions and other options in your activities.
Beginning with Android 3.0 (API level 11), Android-powered devices are no longer required to provide a dedicated Menu button. With this change, Android apps should migrate away from a dependence on the traditional 6-item menu panel and instead provide an action bar to present common user actions.
Although the design and user experience for some menu items have changed, the semantics to define a set of actions and options is still based on the Menu APIs. This guide shows how to create the three fundamental types of menus or action presentations on all versions of Android:
Options menu and action bar
The options menu is the primary collection of menu items for an activity. It's where you should place actions that have a global impact on the app, such as "Search," "Compose email," and "Settings."
If you're developing for Android 2.3 or lower, users can reveal the options menu panel by pressing the Menu button.
On Android 3.0 and higher, items from the options menu are presented by the action bar as a combination of on-screen action items and overflow options. Beginning with Android 3.0, the Menu button is deprecated (some devices don't have one), so you should migrate toward using the action bar to provide access to actions and other options.
The options menu
The options menu is where you should include actions and other options that are relevant to the current activity context, such as "Search," "Compose email," and "Settings."
Where the items in your options menu appear on the screen depends on the version for which you've developed your application:
If you've developed your application for Android 2.3.x (API level 10) or lower, the contents of your options menu appear at the bottom of the screen when the user presses the Menu button, as shown in figure 1. When opened, the first visible portion is the icon menu, which holds up to six menu items. If your menu includes more than six items, Android places the sixth item and the rest into the overflow menu, which the user can open by selecting More.
If you've developed your application for Android 3.0 (API level 11) and higher, items from the options menu are available in the action bar. By default, the system places all items in the action overflow, which the user can reveal with the action overflow icon on the right side of the action bar (or by pressing the device Menu button, if available). To enable quick access to important actions, you can promote a few items to appear in the action bar by adding android:showAsAction="ifRoom" to the corresponding elements (see image below).
Action bar on android 3.0+ with menu button on the right
Action bar on android 2.3 http://developer.android.com/images/options_menu.png
Options menu on android 2.3 or lower
