This is an example of how to create a MenuBar using the Google Web Toolkit, that is an open source set of tools that allows web developers to create and maintain complex JavaScript front-end applications in Java. Creating a MenuBar implies that you should:
- The
MenuExampleclass implements thecom.google.gwt.core.client.EntryPointinterface to allow the class to act as a module entry point. It overrides itsonModuleLoad()method. It also implements thecom.google.gwt.user.client.Commandso that it can have a Command associated with it that it executes when it is chosen by the user. - Create a new Instance of MenuBar.
- Create sub- MenuBar items and add Items to them.
- Add the sub- MenuBar items to the MenuBar.
- Add the MenuBarto the
RootPanel, that is the panel to which all other widgets must ultimately be added.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.enterprise;
import com.google.gwt.user.client.Command;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.MenuBar;
import com.google.gwt.user.client.ui.MenuItem;
public class MenuExample implements EntryPoint, Command {
@Override
public void onModuleLoad() {
//Create new Instance of MenuBar
MenuBar menu = new MenuBar();
menu.setAutoOpen(true);
//Set subMenu Items for Item 2 of Menu0
MenuBar subMenu = new MenuBar(true);
subMenu.addItem("Item 0,2,0", true, this);
subMenu.addItem("Item 0,2,1", true, this);
subMenu.addItem("Item 0,2,2", true, this);
//Set Menu0 Items
MenuBar menu0 = new MenuBar(true);
menu0.addItem("Item 0,0", true, this);
menu0.addItem("Item 0,1", true, this);
menu0.addItem("Item 0,2", true, subMenu);
//Set Menu1 Items
MenuBar menu1 = new MenuBar(true);
menu1.addItem("Item 1,0", true, this);
menu1.addItem("Item 1,1", true, this);
menu1.addItem("Item 1,2", true, this);
//Set Menu2 Items
MenuBar menu2 = new MenuBar(true);
menu2.addItem("Item 2,0", this);
menu2.addItem("Item 2,1", this);
menu2.addItem("Item 2,2", true, this);
//Add Menu Items to Menu
menu.addItem(new MenuItem("Menu 0", menu0));
menu.addItem(new MenuItem("Menu 1", menu1));
menu.addItem(new MenuItem("Menu 2", menu2));
menu.setWidth("100%");
//Add Menu to Root Panel
RootPanel.get().add(menu);
}
@Override
public void execute() {
return;
}
}
This was an example of how to create a MenuBar with the Google Web Toolkit.
