Menu Shortcuts
菜单快捷键
The ability to specify menu shortcuts is one of the features in JDK 1.1 -- where menu choices can be selected via the keyboard instead of with the mouse.
在jdk1.1中提供了菜单快捷键的实现.快捷键---就是利用键盘取代鼠标选择菜单项.
For example:
一个例子:
//导入需要的包
import java.awt.*;
import java.awt.event.*;
//Menu类,实现ActionListener接口
public class menu implements ActionListener {
public void actionPerformed(ActionEvent e)
{
String lab = ((MenuItem)e.getSource()).getLabel();
System.out.println("label = " + lab);
if(lab.equals("Exit"))
{
System.exit(0);
}
}
public static void main(String args[])
{
Frame f = new Frame("testing");
Menu m = new Menu("File");
menu acl = new menu();
MenuItem mi1 = new MenuItem("Open");
mi1.addActionListener(acl);
m.add(mi1);
MenuItem mi2 = new MenuItem("Save");
mi2.addActionListener(acl);
m.add(mi2);
//创建快捷方式,这里将会依赖于平台,使用快捷键,在Windows下,将会是C+E
MenuShortcut ms3 = new MenuShortcut(KeyEvent.VK_E);
MenuItem mi3 = new MenuItem("Exit", ms3);
mi3.addActionListener(acl);
m.add(mi3);
MenuBar mb = new MenuBar();
mb.add(m);
f.setMenuBar(mb);
f.setSize(200, 200);
f.setVisible(true);
}
}
The example sets up a frame, which is a top-level application window. The frame contains a menu bar, and the menu bar contains a single pull-down menu named "File." The menu offers choices for Open, Save, and Exit, with Exit having a keyboard shortcut set up for it that specifies the virtual key code "E."
这个例子构建了一个Frame作为顶层窗口,窗口有一个菜单栏,菜单栏里只有File一项菜单,File菜单提供了Open,Save,Exit三项,Exit项绑定了一个快捷键E.
How the shortcut gets invoked varies, depending on the platform in question. For example, with Windows you use Ctrl-E so that when a user types Ctrl-E within the window containing the menu bar, the Exit command is invoked.
快捷键通过什么方式执行是依赖于平台的,比如,在Windows下,对应的是Ctrl-E,当你按下Ctrl-E时,Exit命令就会执行.
One last thing: this example doesn't actually(事实上,居然) have a command structure(构建,构造) set up for it, but instead invokes actionPerformed to demonstrate(证明) that the command processing structure is in place.
最后一件事:这个例子实际上并没有构建一个命令处理结构，但是只是调用actionPerformed证明命令处理结构已经正确执行了。