如何让我选择水果列表框就显示水果列表,选择蔬菜列表框就显示蔬菜列表呢
import java.awt.*;
import java.awt.event.*;class MyPanel1 extends Panel implements ItemListener
{
Choice c;
List l;
List l2;
MyPanel1()
{ Choice c=new Choice();
c.addItem("水果");
c.addItem("蔬菜");
List l=new List(10);
l.add("苹果");
l.add("菠萝");
List l2=new List(10);
l2.add("黄瓜");
l2.add("冬瓜");
l2.setVisible(false);
add(c);
add(l);
add(l2);
c.addItemListener(this);
} public void itemStateChanged(ItemEvent e)
{
//String[] items=l.getSelectedItems();
}
}class MyFrame1 extends Frame
{
MyFrame1()
{
setTitle("列表框&选择框的应用");
setSize(400,400);
MyPanel1 Panel1=new MyPanel1();
add(Panel1);
}
}public class Test4
{
public static void main(String[] args)
{
MyFrame1 s1=new MyFrame1();
s1.setVisible(true);
}
}
import java.awt.*;
import java.awt.event.*;class MyPanel1 extends Panel implements ItemListener
{
Choice c;
List l;
List l2;
MyPanel1()
{ Choice c=new Choice();
c.addItem("水果");
c.addItem("蔬菜");
List l=new List(10);
l.add("苹果");
l.add("菠萝");
List l2=new List(10);
l2.add("黄瓜");
l2.add("冬瓜");
l2.setVisible(false);
add(c);
add(l);
add(l2);
c.addItemListener(this);
} public void itemStateChanged(ItemEvent e)
{
//String[] items=l.getSelectedItems();
}
}class MyFrame1 extends Frame
{
MyFrame1()
{
setTitle("列表框&选择框的应用");
setSize(400,400);
MyPanel1 Panel1=new MyPanel1();
add(Panel1);
}
}public class Test4
{
public static void main(String[] args)
{
MyFrame1 s1=new MyFrame1();
s1.setVisible(true);
}
}
解决方案 »
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{
//String[] items=l.getSelectedItems();
if (e.getSource().equals(c)) {
String s;
s= e.getItemSelectable().toString();
switch (s)
{
case "":
l.add();
break;
case "":
l2.add;
break;
}
}
参考一下.............
}
import java.awt.event.*;
class Test
{
Test()
{
Choice ch1=new Choice();
Choice ch2=new Choice();
ch1.add("蔬菜");
ch1.add("水果");
Panel p=new Panel();
p.add(ch1);
p.add(ch2);
Frame f=new Frame();
f.add(p);
f.setSize(300,300);
f.show();
ch1.addItemListener(new MyAdapter());
}
private class MyAdapter implements ItemListener
{
public void itemStateChanged(ItemEvent e)
{
System.out.println(e.getItem().toString());
}
}
public static void main(String []args)
{
new Test();
}
}
import javax.swing.DefaultListModel;
public class ChoiceFrame extends javax.swing.JFrame {
private DefaultListModel lm1 = new DefaultListModel();
private DefaultListModel lm2 = new DefaultListModel();
public ChoiceFrame() {
initComponents();
lm1.addElement("香蕉");
lm1.addElement("橘子");
lm1.addElement("苹果");
lm2.addElement("白菜");
lm2.addElement("辣椒");
}
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
jList1 = new javax.swing.JList();
jList2 = new javax.swing.JList(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setLayout(new java.awt.GridLayout(1, 2)); jList1.setModel(new javax.swing.AbstractListModel() {
String[] strings = { "水果", "蔬菜" };
public int getSize() { return strings.length; }
public Object getElementAt(int i) { return strings[i]; }
});
jList1.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
jList1.addListSelectionListener(new javax.swing.event.ListSelectionListener() {
public void valueChanged(javax.swing.event.ListSelectionEvent evt) {
jList1ValueChanged(evt);
}
}); jPanel1.add(jList1); jPanel1.add(jList2); getContentPane().add(jPanel1, java.awt.BorderLayout.CENTER); pack();
} private void jList1ValueChanged(javax.swing.event.ListSelectionEvent evt) {
if(jList1.getSelectedValue().equals("水果"))
{
jList2.setModel(lm1);
}
else
{
jList2.setModel(lm2);
}
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new ChoiceFrame().setVisible(true);
}
});
}
private javax.swing.JList jList1;
private javax.swing.JList jList2;
private javax.swing.JPanel jPanel1;
}