5.18. MenuBar

The MenuBar component allows creating horizontal dropdown menus, much like the main menu in desktop applications.

Figure 5.56. Menu Bar

Menu Bar

Creating a Menu

The actual menu bar component is first created as follows:

MenuBar menubar = new MenuBar();

You insert the top-level menu items to the MenuBar object with the addItem() method. It takes a string label, an icon resource, and a command as its parameters. The icon and command are not required and can be null. The addItem() method returns a MenuBar.MenuItem object, which you can use to add sub-menu items. The MenuItem has an identical addItem() method.

For example (the command is explained later):

// A top-level menu item that opens a submenu
MenuItem drinks = barmenu.addItem("Beverages", null, null);

// Submenu item with a sub-submenu
MenuItem hots = drinks.addItem("Hot", null, null);
    new ThemeResource("icons/tea-16px.png"),    mycommand);
    new ThemeResource("icons/coffee-16px.png"), mycommand);

// Another submenu item with a sub-submenu
MenuItem colds = drinks.addItem("Cold", null, null);
colds.addItem("Milk",      null, mycommand);
colds.addItem("Weissbier", null, mycommand);

// Another top-level item
MenuItem snacks = barmenu.addItem("Snacks", null, null);
snacks.addItem("Weisswurst", null, mycommand);
snacks.addItem("Bratwurst",  null, mycommand);
snacks.addItem("Currywurst", null, mycommand);
// Yet another top-level item
MenuItem servs = barmenu.addItem("Services", null, null);
servs.addItem("Car Service", null, mycommand);

Handling Menu Selection

Menu selection is handled by executing a command when the user selects an item from the menu. A command is a call-back class that implements the MenuBar.Command interface.

// A feedback component
final Label selection = new Label("-");

// Define a common menu command for all the menu items.
MenuBar.Command mycommand = new MenuBar.Command() {
    public void menuSelected(MenuItem selectedItem) {
        selection.setValue("Ordered a " +
                           selectedItem.getText() +
                           " from menu.");

Menu Items

Menu items have properties such as a caption, icon, enabled, visible, and description (tooltip). The meaning of these is the same as for components.

Submenus are created by adding sub-items to an item with addItem() or addItemBefore().

The command property is a MenuBar.Command that is called when the particular menu item is selected. The menuSelected() callback gets the clicked menu item as its parameter.

Menus can have separators, which are defined before or after an item with addSeparatorBefore() or addSeparator() on the item, respectively.

MenuItem drinks = barmenu.addItem("Beverages", null, null);

// A sub-menu item after a separator
drinks.addItem("Quit Drinking", null, null);

Enabling checkable on an menu item with setCheckable() allows the user to switch between checked and unchecked state by clicking on the item. You can set the checked state with setChecked(). Note that if such an item has a command, the checked state is not flipped automatically, but you need to do it explicitly.

Menu items have various other properties as well, see the API documentation for more details.

CSS Style Rules

.v-menubar { }
  .v-menubar-submenu { }
    .v-menubar-menuitem { }
      .v-menubar-menuitem-caption { }
    .v-menubar-menuitem-selected { }
    .v-menubar-submenu-indicator { }

The menu bar has the overall style name .v-menubar. Each menu item has .v-menubar-menuitem style normally and additionally .v-menubar-selected when the item is selected, that is, when the mouse pointer hovers over it. The item caption is inside a v-menubar-menuitem-caption. In the top-level menu bar, the items are directly under the component element.

Submenus are floating v-menubar-submenu elements outside the menu bar element. Therefore, you should not try to match on the component element for the submenu popups. In submenus, any further submenu levels are indicated with a v-menubar-submenu-indicator.

Styling Menu Items

You can set the CSS style name for the menu items with setStyleName(), just like for components. The style name will be prepended with v-menubar-menuitem-. As MenuBar does not indicate the previous selection in any way, you can do that by highlighting the previously selected item. However, beware that the selected style for menu items, that is, v-menubar-menuitem-selected, is reserved for mouse-hover indication.

MenuBar barmenu = new MenuBar();
// A feedback component
final Label selection = new Label("-");

// Define a common menu command for all the menu items
MenuBar.Command mycommand = new MenuBar.Command() {
    MenuItem previous = null;

    public void menuSelected(MenuItem selectedItem) {
        selection.setValue("Ordered a " +
                selectedItem.getText() +
                " from menu.");

        if (previous != null)
        previous = selectedItem;
// Put some items in the menu
barmenu.addItem("Beverages", null, mycommand);
barmenu.addItem("Snacks", null, mycommand);
barmenu.addItem("Services", null, mycommand);

You could then style the highlighting in CSS as follows:

.mybarmenu .v-menubar-menuitem-highlight {
    background: #000040; /* Dark blue */
I. Introduction
1. Introduction
1.1. Overview
1.2. Example Application Walkthrough
1.3. Support for the Eclipse IDE
1.4. Goals and Philosophy
1.5. Background
2. Getting Started with Vaadin
2.1. Overview
2.2. Setting up the Development Environment
2.3. Overview of Vaadin Libraries
2.4. Installing Vaadin Plugin for Eclipse
2.5. Creating and Running a Project with Eclipse
2.6. Using Vaadin with Maven
2.7. Creating a Project with NetBeans IDE
2.8. Creating a Project with IntelliJ IDEA
2.9. Vaadin Installation Package
2.10. Using Vaadin with Scala
3. Architecture
3.1. Overview
3.2. Technological Background
3.3. Client-Side Engine
3.4. Events and Listeners
II. Server-Side Framework
4. Writing a Server-Side Web Application
4.1. Overview
4.2. Building the UI
4.3. Handling Events with Listeners
4.4. Images and Other Resources
4.5. Handling Errors
4.6. Notifications
4.7. Application Lifecycle
4.8. Deploying an Application
5. User Interface Components
5.1. Overview
5.2. Interfaces and Abstractions
5.3. Common Component Features
5.4. Field Components
5.5. Component Extensions
5.6. Label
5.7. Link
5.8. TextField
5.9. TextArea
5.10. PasswordField
5.11. RichTextArea
5.12. Date and Time Input with DateField
5.13. Button
5.14. CheckBox
5.15. Selecting Items
5.16. Table
5.17. Tree
5.18. MenuBar
5.19. Embedded Resources
5.20. Upload
5.21. ProgressBar
5.22. Slider
5.23. Calendar
5.24. Component Composition with CustomComponent
5.25. Composite Fields with CustomField
6. Managing Layout
6.1. Overview
6.2. UI, Window, and Panel Content
6.3. VerticalLayout and HorizontalLayout
6.4. GridLayout
6.5. FormLayout
6.6. Panel
6.7. Sub-Windows
6.8. HorizontalSplitPanel and VerticalSplitPanel
6.9. TabSheet
6.10. Accordion
6.11. AbsoluteLayout
6.12. CssLayout
6.13. Layout Formatting
6.14. Custom Layouts
7. Visual User Interface Design with Eclipse
7.1. Overview
7.2. Creating a New Composite
7.3. Using The Visual Editor
7.4. Structure of a Visually Editable Component
8. Themes
8.1. Overview
8.2. Introduction to Cascading Style Sheets
8.3. Syntactically Awesome Stylesheets (Sass)
8.4. Creating and Using Themes
8.5. Creating a Theme in Eclipse
8.6. Responsive Themes
9. Binding Components to Data
9.1. Overview
9.2. Properties
9.3. Holding properties in Items
9.4. Creating Forms by Binding Fields to Items
9.5. Collecting Items in Containers
10. Vaadin SQLContainer
10.1. Architecture
10.2. Getting Started with SQLContainer
10.3. Filtering and Sorting
10.4. Editing
10.5. Caching, Paging and Refreshing
10.6. Referencing Another SQLContainer
10.7. Using FreeformQuery and FreeformStatementDelegate
10.8. Non-implemented methods of Vaadin container interfaces
10.9. Known Issues and Limitations
11. Advanced Web Application Topics
11.1. Handling Browser Windows
11.2. Embedding UIs in Web Pages
11.3. Debug Mode and Window
11.4. Request Handlers
11.5. Shortcut Keys
11.6. Printing
11.7. Google App Engine Integration
11.8. Common Security Issues
11.9. Navigating in an Application
11.10. Advanced Application Architectures
11.11. Managing URI Fragments
11.12. Drag and Drop
11.13. Logging
11.14. JavaScript Interaction
11.15. Accessing Session-Global Data
11.16. Server Push
12. Portal Integration
12.1. Overview
12.2. Creating a Portlet Project in Eclipse
12.3. Portlet UI
12.4. Deploying to a Portal
12.5. Installing Vaadin in Liferay
12.6. Handling Portlet Requests
12.7. Handling Portlet Mode Changes
12.8. Non-Vaadin Portlet Modes
12.9. Vaadin IPC for Liferay
III. Client-Side Framework
13. Client-Side Vaadin Development
13.1. Overview
13.2. Installing the Client-Side Development Environment
13.3. Client-Side Module Descriptor
13.4. Compiling a Client-Side Module
13.5. Creating a Custom Widget
13.6. Debugging Client-Side Code
14. Client-Side Applications
14.1. Overview
14.2. Client-Side Module Entry-Point
14.3. Compiling and Running a Client-Side Application
14.4. Loading a Client-Side Application
15. Client-Side Widgets
15.1. Overview
15.2. GWT Widgets
15.3. Vaadin Widgets
16. Integrating with the Server-Side
16.1. Overview
16.2. Starting It Simple With Eclipse
16.3. Creating a Server-Side Component
16.4. Integrating the Two Sides with a Connector
16.5. Shared State
16.6. RPC Calls Between Client- and Server-Side
16.7. Component and UI Extensions
16.8. Styling a Widget
16.9. Component Containers
16.10. Creating Add-ons
16.11. Migrating from Vaadin 6
16.12. Integrating JavaScript Components and Extensions
IV. Vaadin Add-ons
17. Using Vaadin Add-ons
17.1. Overview
17.2. Downloading Add-ons from Vaadin Directory
17.3. Installing Add-ons in Eclipse with Ivy
17.4. Using Add-ons in a Maven Project
17.5. Troubleshooting
18. Vaadin Charts
18.1. Overview
18.2. Installing Vaadin Charts
18.3. Basic Use
18.4. Chart Types
18.5. Chart Configuration
18.6. Chart Data
18.7. Advanced Uses
18.8. Timeline
19. Vaadin JPAContainer
19.1. Overview
19.2. Installing
19.3. Defining a Domain Model
19.4. Basic Use of JPAContainer
19.5. Entity Providers
19.6. Filtering JPAContainer
19.7. Querying with the Criteria API
19.8. Automatic Form Generation
19.9. Using JPAContainer with Hibernate
20. Mobile Applications with TouchKit
20.1. Overview
20.2. Considerations Regarding Mobile Browsing
20.3. Installing Vaadin TouchKit
20.4. Importing the Vornitologist Demo
20.5. Creating a New TouchKit Project
20.6. Elements of a TouchKit Application
20.7. Mobile User Interface Components
20.8. Advanced Mobile Features
20.9. Offline Mode
20.10. Building an Optimized Widget Set
20.11. Testing and Debugging on Mobile Devices
21. Vaadin TestBench
21.1. Overview
21.2. Installing Vaadin TestBench
21.3. Preparing an Application for Testing
21.4. Using Vaadin TestBench Recorder
21.5. Developing JUnit Tests
21.6. Taking and Comparing Screenshots
21.7. Running Tests in a Distributed Environment
21.8. Headless Testing
21.9. Known Issues
A. Songs of Vaadin