1 import java.awt.event.*;
2 import java.awt.*;
3 import javax.swing.*;
4
5 /*
6 * 有四个多选框，每选一项就在文本区中增加一个对应项目的名称
7 * 取消选择，则将取消选择的项目从文本区中清除，但保留已选项目及其顺序。
8 * */
9 class Ex_6_1 extends JFrame implements ItemListener {
10
11 private static final long serialVersionUID = 1L;
12 JCheckBox box1;
13 JCheckBox box2;
14 JCheckBox box3;
15 JCheckBox box4;
16 JTextArea tArea;
17 String text="";
18 String sportStr[][] = {
19 {"乒乓球","0"},
20 {"羽毛球","0"},
21 {"篮球","0"},
22 {"游泳","0"}
23 };
24
25 Ex_6_1(){
26 box1 = new JCheckBox("乒乓球");
27 box2 = new JCheckBox("羽毛球");
28 box3 = new JCheckBox("篮球");
29 box4 = new JCheckBox("游泳");
30 tArea = new JTextArea("选择运动项目");
31 setLayout(new GridLayout(5,1));
32 setSize(300,500);
33 setTitle("多选按钮与文本区练习");
34
35 this.add(box1); this.add(box2);this.add(box3);this.add(box4);
36 this.add(tArea);
37
38 box1.addItemListener(this);
39 box2.addItemListener(this);
40 box3.addItemListener(this);
41 box4.addItemListener(this);
42 }
43
44 @Override
45 /* JCheckBox要注册的事件接口是ItemListener */
46 public void itemStateChanged(ItemEvent arg0) {
47 text = ""; //每一轮点击都清空text，重新设置text字符串的内容
48 if (arg0.getItem() == box1){
49 if (sportStr[0][1] == "0") sportStr[0][1]="1";
50 else sportStr[0][1]="0"; //根据标识位反向设置
51 }else if (arg0.getItem() == box2){
52 if (sportStr[1][1] == "0") sportStr[1][1]="1";
53 else sportStr[1][1]="0";
54 }else if (arg0.getItem() == box3){
55 if (sportStr[2][1] == "0") sportStr[2][1]="1";
56 else sportStr[2][1]="0";
57 }else if (arg0.getItem() == box4){
58 if (sportStr[3][1] == "0") sportStr[3][1]="1";
59 else sportStr[3][1]="0";
60 }
61
62 for (int i=0;i<sportStr.length;i++){
63 if (sportStr[i][1] == "1")
64 text = text + "选择了" + sportStr[i][0] + "\n";
65 }
66 tArea.setText(text);
67 }
68
69 }
