对于带复选项的菜单项,当菜单项的复选状态发生变化时,会引发()事件
A.ActionEvent
B.ItemEvent
C.MouseEvent
D.MenuEvent
A.ActionEvent
B.ItemEvent
C.MouseEvent
D.MenuEvent
A.ctionListener
B.ItemListener
C.MouseListener
D.MenuListener
A.itemStateChanged
B.itemStateSet
C.itemSelected
D.itemChanged
import java.awt.*;
import java.awt.event.*;
class CanvasWithPopup extends Canvas{
Popupmenu popup;
CanvasWithPopup(PopupMenu popup){
enableEvents(AWTEvent.MOUSE EVENT
MASK):
this.popup=popup;
}
void addPopup(){
add(popup);
}
void removePopup(){
remove(popup);
}
protected void processMouseEvent(MouseEvent
evt){
if(popup.getParent()!=null&&evt.isPop-
upTrigger()){
popup.show(evt.getComponent(),evt.getX(),
evt.getY());
}
super.processMouseEvent(evt);
}
}
public class java3 extends Frame. implements Item-
Listener,ActionListener{
Checkbox cb=new Checkbox("弹出菜单",
false);
CanvasWithPopup canvas;
java3(){
super("java3");
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
add(cb,BorderLayout.NORTH);
cb.addhemListener(this);
PopupMenu popup=new PopupMenu("Button
Control"):
popup.add("iteml");
popup.add("item2");
popup.addActionListener(this);
canvas=new CanvasWithPopup(popup);
add(canvas,BorderLayout.CENTER);
setSize(100,200);
show();
}
在Windows的菜单中,标有“√’的菜单项表示()。
A.此菜单项对应一个级联菜单
B.执行此菜单命令将打开一个对话框
C.该菜单是一个复选菜单
D.该菜单为单选菜单
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