org.eclipse.ui.menus extension point

    In the development of eclipse plug-ins, commands are often used to declare and implement a menu. The specific steps are: 1. Declare a command; 2. Create a menu item using the command; 3. Create a handler corresponding to the command.
   
    1. Declare a command through the org.eclipse.ui.commands extension point, and each command is a declaration of a ui function point.
    Declare a category to manage your own commands:
    id:cn.com.aquarion.category
    name:MyCategory
    description: My command's group
    Declare a command to open the view:
    id:com.aquarion.commands.openView
    name:Open my view
    categoryId :cn.com.aquarion.category

    2. Create a menu item using the command through the org.eclipse.ui.menus extension point.
    Declare a menuContribution, define the location where the command appears, and define its visibility
    locationURI: menu:org.eclipse. ui.main.menu?after=additions; the location where the command will appear, this identifies the menu item as a new one and appears in the main menu bar
    declare a menu label under menuContribution
    : Fav
    id:com.aquarion.menus.viewMenu
    mnemonic:v; indicates that the keyboard accessibility
    uses a command
    commandId: com.aquarion.commands.openView under the menu, that is, the command
    id triggered when the menu is selected: com.aquarion.menu. openView
    mnemonic:O
    icon: icon

    After the above two steps, run the plugin to see that the menu items and menus have appeared in the main menu. If you need the menu item to appear in the toolbar, you can change the value of locationURI to toolbar:org.eclipse.ui.main.toolbar?after=additon.
This attribute identifies the location where the menu appears, so we can also use the menu we defined. Declare under the existing menu, for example, to create a new menu into the existing eclipse menu, the value of locationURI can be defined as follows:
    menu:help?after=additions
    menu:navigate?after=open.ext2
    menu:window ?after=newEditor
    menu:file?after=open.ext
   
    As seen in the above example, locationURI is divided into three parts: scheme (scheme), such as menu:, identifier (identifier) ​​such as: help and parameter list (argument list) such as after=additions
   
    scheme identifies the type of UI object to which the new item will be added. It can be one of the following values:
    menu: the program's main menu or view's drop-down menu
    popup: the view's or editor's context menu
    toolbar: the program's toolbar or view's tools Bar
   
    Identifier (ID): For any view, this identifier matches one of its toolbar identifier or context menu identifier or drop down menu identifier. Commonly used are:
    org.eclipse.ui.main.menu------------eclipse's main menu identifier
    org.eclipse.ui.main.toolbar---------eclipse The main toolbar identifier
    org.eclipse.ui.popup.any------------ any context menu

    argument list: allows fine-grained definition of the location of new items. After and before are the layout of the new item, "=", and finally the identifier of an item in the menu, context menu or toolbar. The last identifier can also be additions, indicating that the new item is in the default position.