!!!!!!!!!!求教各位高手!此段关于控件的代码为什么不能编译? 很简单的代码,可编译提示我class checker 需要抽象定义 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 你没有实现 void itemStateChanged(ItemEvent e) 那是因为你实现了ItemListener接口,却没有对ItemListener中的itemStateChanged(ItemEvent evt)方法进行重载.你只要把public void actionPerformed(ActionEvent event)该为:public void itemStateChanged(ItemEvent event)就没问题了. 按你程序的意思,只需要把 public class checker extends Applet implements ItemListener改为 public class checker extends Applet implements ActionListener就可以了 那这个问题出在哪里?import java.applet.Applet;import java.awt.*;import java.awt.event.*;public class sandwich extends Applet{ Menu Panel1; Ingredients Panel2; public void init(){ setLayout(new GridLayout(1,2)); Panel1 = new Menu(); add(Panel1); Panel2 = new Ingredients(); Panel1.sandwich1.addItemListener(this); Panel1.sandwich2.addItemListener(this); Panel1.sandwich3.addItemListener(this); add(Panel2); }}public void itemStateChanged(ItemEvent event){if(event.getItemSelectable() == Panel1.Sandwich1){ panel2.Ingredient1.setState(true); panel2.Ingredient2.setState(false); panel2.Ingredient3.setState(true); panel2.Ingredient4.setState(false); panel2.pricebox.setText("price: $2.95");}if(event.getItemSelectable() == Panel1.Sandwich2){ panel2.Ingredient1.setState(false); panel2.Ingredient2.setState(true); panel2.Ingredient3.setState(true); panel2.Ingredient4.setState(true); panel2.pricebox.setText("price: $2.95");}if(event.getItemSelectable() == Panel1.Sandwich3){ panel2.Ingredient1.setState(true); panel2.Ingredient2.setState(true); panel2.Ingredient3.setState(true); panel2.Ingredient4.setState(true); panel2.pricebox.setText("price: $4.00");}}class Menu extends Panel{ CheckboxGroup CGroup; Checkbox sandwich1,sandwich2,sandwich3; TextField Pricebox; Menu(){ CGroup = new CheckboxGroup(); add(sandwich1 = new Checkbox("Sandwich 1",CGroup,false)); add(sandwich2 = new Checkbox("Sandwich 2",CGroup,false)); add(sandwich3 = new Checkbox("Sandwich 3",CGroup,false)); Pricebox = new TextField(15); add(Pricebox); }}class Ingredients extends Panel{ checkbox Ingredient1,Ingredient2,Ingredient3,Ingredient4; Ingredients(){ add(Checkbox Ingredient1 = new Checkbox("turkey")); add(Checkbox Ingredient2 = new Checkbox("r.beef")); add(Checkbox Ingredient3 = new Checkbox("pickle")); add(Checkbox Ingredient4 = new Checkbox("tomato")); }} 编译提示设置状态代码段中的FALSE是未定义的变量,是为什么? 删除xml节点操作问题 java序列与反序列主要是由于什么样的需求而发明的? JAVA开发的代理程序 求问一个很郁闷的问题 前辈请留一下步 请问:我在输出字符串的时候怎么才可以连续的输出同样的? 求助关于JMF 高分征询:如何在五子棋中输入棋谱库的问题 谁有资料阿? 如何在linux环境下设置jdk1.3.1的CLASSPATH 我的JB6无法编译java.rmi.*,说是找不到这个包,我该去哪里下载 谁有Tomcat 的配置说明文档? 紧急求救----如何用java编游戏杆的接口程序???????
把 public class checker extends Applet implements ItemListener
改为 public class checker extends Applet implements ActionListener
就可以了
import java.awt.*;
import java.awt.event.*;public class sandwich extends Applet{
Menu Panel1;
Ingredients Panel2;
public void init(){
setLayout(new GridLayout(1,2));
Panel1 = new Menu();
add(Panel1);
Panel2 = new Ingredients();
Panel1.sandwich1.addItemListener(this);
Panel1.sandwich2.addItemListener(this);
Panel1.sandwich3.addItemListener(this);
add(Panel2);
}
}
public void itemStateChanged(ItemEvent event){
if(event.getItemSelectable() == Panel1.Sandwich1){
panel2.Ingredient1.setState(true);
panel2.Ingredient2.setState(false);
panel2.Ingredient3.setState(true);
panel2.Ingredient4.setState(false);
panel2.pricebox.setText("price: $2.95");
}
if(event.getItemSelectable() == Panel1.Sandwich2){
panel2.Ingredient1.setState(false);
panel2.Ingredient2.setState(true);
panel2.Ingredient3.setState(true);
panel2.Ingredient4.setState(true);
panel2.pricebox.setText("price: $2.95");
}
if(event.getItemSelectable() == Panel1.Sandwich3){
panel2.Ingredient1.setState(true);
panel2.Ingredient2.setState(true);
panel2.Ingredient3.setState(true);
panel2.Ingredient4.setState(true);
panel2.pricebox.setText("price: $4.00");
}}class Menu extends Panel{
CheckboxGroup CGroup;
Checkbox sandwich1,sandwich2,sandwich3;
TextField Pricebox;
Menu(){
CGroup = new CheckboxGroup();
add(sandwich1 = new Checkbox("Sandwich 1",CGroup,false));
add(sandwich2 = new Checkbox("Sandwich 2",CGroup,false));
add(sandwich3 = new Checkbox("Sandwich 3",CGroup,false));
Pricebox = new TextField(15);
add(Pricebox);
}
}class Ingredients extends Panel{
checkbox Ingredient1,Ingredient2,Ingredient3,Ingredient4; Ingredients(){
add(Checkbox Ingredient1 = new Checkbox("turkey"));
add(Checkbox Ingredient2 = new Checkbox("r.beef"));
add(Checkbox Ingredient3 = new Checkbox("pickle"));
add(Checkbox Ingredient4 = new Checkbox("tomato"));
}
}