我希望每次用户在JLabel中选择从文本文件中获取其值的选项时进行JComboBox更改，请真正需要帮助....
import javax.swing.*;
import javax.swing.border.*;
import java.util.*;
import java.util.List;
import java.io.IOException;
import java.util.Scanner;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.applet.*;
public class MusicOnWeb extends JApplet {
JPanel P = new JPanel();
JLabel Title = new JLabel();
JLabel Logo = new JLabel();
JLabel Category = new JLabel();
JLabel List = new JLabel();
JLabel Image = new JLabel();
JSeparator jSeparator1 = new JSeparator();
JSeparator jSeparator2 = new JSeparator();
JSeparator jSeparator3 = new JSeparator();
JSeparator jSeparator4 = new JSeparator();
JSeparator jSeparator5 = new JSeparator();
JButton Cc = new JButton();
JButton Pp = new JButton();
JButton Jz = new JButton();
JButton Wn = new JButton();
JButton Cart = new JButton();
JComboBox Combo1 = new JComboBox();
JComboBox Combo2 = new JComboBox();
JComboBox Combo3 = new JComboBox();
JComboBox Combo4 = new JComboBox();
Font f = new Font("Lucida Calligraphy", Font.BOLD,25);
final java.text.SimpleDateFormat sdf = new java.text.SimpleDateFormat("MMMM dd yyyy GGG hh:mm:ss aaa");
JLabel TimeLabel = new JLabel();
ActionListener al = new ActionListener() {
public void actionPerformed(ActionEvent ae) {
TimeLabel.setText(sdf.format(new java.util.Date()));
}
};
String[] CB1 = new String[5];
String[] CB2 = new String[5];
String[] CB3 = new String[5];
String[] CB4 = new String[5];
String Music [ ] = {" Seal.jpg"};
GridBagConstraints gbc;
public void init() {
P.setBackground(new Color(102, 102, 102));
P.setBorder(javax.swing.BorderFactory.createCompoundBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED, new java.awt.Color(255, 0, 51), new java.awt.Color(0, 153, 255), new java.awt.Color(0, 204, 153), new java.awt.Color(0, 204, 102)), javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0), 3)));
P.setLayout(new GridBagLayout());
try {
File F= new File("Classics.txt");
Scanner inFile = new Scanner(new FileReader(F)).useDelimiter("\\' '| \r");
int i=0;
while (inFile.hasNextLine()){
CB1[i] = inFile.nextLine();
i++;
}} catch (Exception e) {
}
try {
File F= new File("Western.txt");
Scanner inFile = new Scanner(new FileReader(F)).useDelimiter("\\' '| \r");
int i=0;
while (inFile.hasNextLine()){
CB2[i] = inFile.nextLine();
i++;
}}catch (Exception e) {
}
try {
File F= new File("Pop.txt");
Scanner inFile = new Scanner(new FileReader(F)).useDelimiter("\\' '| \r");
int i=0;
while (inFile.hasNextLine()){
CB4[i] = inFile.nextLine();
i++;
}}catch (Exception e) {
}
try {
File F= new File("Jazz.txt");
Scanner inFile = new Scanner(new FileReader(F)).useDelimiter("\\' '| \r");
int i=0;
while (inFile.hasNextLine()){
CB3[i] = inFile.nextLine();
i++;
}}catch (Exception e) {
}
Title.setFont(new Font("Lucida Calligraphy", 1, 27));
Title.setForeground(new Color(102, 102, 255));
Title.setHorizontalAlignment(SwingConstants.CENTER);
Title.setText("<HTML><center><b><u>MusicOnWeb</u></b><BR>An Online Music Store</HTML>");
Title.setBorder(javax.swing.BorderFactory.createLineBorder(new Color(0, 0, 0)));
gbc = new GridBagConstraints();
gbc.gridx = 1;
gbc.gridy = 0;
gbc.gridwidth = 10;
gbc.ipadx = 440; // To resize components
gbc.ipady = 25;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(26, 45, 0, 0); // To move components
P.add(Title, gbc);
Logo.setIcon(new ImageIcon("C:\\Users\\Kwasi Addai\\Documents\\Java Work\\Project 1\\Logo.jpg"));
Logo.setBorder(javax.swing.BorderFactory.createLineBorder(new Color(0, 0, 0)));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.ipadx = -52;
gbc.ipady = -23;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(26, 46, 0, 0);
P.add(Logo, gbc);
Category.setFont(new Font("Kristen ITC", 1, 24));
Category.setHorizontalAlignment(SwingConstants.CENTER);
Category.setText("Select the Category");
Category.setBorder(javax.swing.BorderFactory.createEtchedBorder(javax.swing.border.EtchedBorder.RAISED, new Color(102, 204, 255), java.awt.Color.red));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 2;
gbc.gridwidth = 3;
gbc.ipadx = 30;
gbc.ipady = 13;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(18, 46, 0, 0);
P.add(Category, gbc);
List.setFont(new Font("Britannic Bold", 0, 27));
List.setHorizontalAlignment(SwingConstants.CENTER);
List.setText("List of CD's Available");
List.setBorder(javax.swing.BorderFactory.createEtchedBorder(java.awt.Color.black, java.awt.Color.white));
gbc = new GridBagConstraints();
gbc.gridx = 6;
gbc.gridy = 2;
gbc.gridwidth = 16;
gbc.gridheight = 2;
gbc.ipadx = 248;
gbc.ipady = 22;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(23, 17, 0, 0);
P.add(List, gbc);
Image.setBorder(javax.swing.BorderFactory.createLineBorder(new Color(0, 0, 0), 3));
Image.setMaximumSize(new Dimension(300, 300));
Image.setMinimumSize(new Dimension(300, 300));
gbc = new GridBagConstraints();
gbc.gridx = 9;
gbc.gridy = 5;
gbc.gridwidth = 12;
gbc.gridheight = 9;
gbc.ipadx = -12;
gbc.ipady = -12;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(8, 40, 0, 0);
P.add(Image, gbc);
TimeLabel.setText("timeLabel");
TimeLabel.setFont(f);
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 16;
gbc.gridwidth = 0;
gbc.ipadx = 278;
gbc.ipady = 33;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(15, 40, 0, 0);
P.add(TimeLabel, gbc);
new javax.swing.Timer(1000,al).start();
jSeparator1.setForeground(new Color(102, 102, 102));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 1;
gbc.gridwidth = 23;
gbc.ipadx = 958;
gbc.ipady = 3;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(20, 15, 0, 16);
P.add(jSeparator1, gbc);
jSeparator2.setBackground(new Color(0, 0, 0));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 4;
gbc.gridwidth = 4;
gbc.ipadx = 340;
gbc.ipady = 2;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(9, 15, 0, 0);
P.add(jSeparator2, gbc);
jSeparator3.setOrientation(SwingConstants.VERTICAL);
gbc = new GridBagConstraints();
gbc.gridx = 4;
gbc.gridy = 2;
gbc.gridheight = 13;
gbc.ipadx = 11;
gbc.ipady = 450;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(-2, 1, 0, 0);
P.add(jSeparator3, gbc);
jSeparator4.setBackground(new Color(0, 0, 0));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 15;
gbc.gridwidth = 23;
gbc.ipadx = 958;
gbc.ipady = 1;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(0, 15, 0, 16);
P.add(jSeparator4, gbc);
jSeparator5.setOrientation(SwingConstants.VERTICAL);
gbc = new GridBagConstraints();
gbc.gridx = 6;
gbc.gridy = 16;
gbc.gridheight = 3;
gbc.ipadx = 11;
gbc.ipady = 95;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(0, 180, 10, 0);
P.add(jSeparator5, gbc);
Cc.setFont(new Font("Tahoma", 3, 20));
Cc.setForeground(new Color(0, 0, 102));
Cc.setText("Classic");
Cc.setBorder(new javax.swing.border.LineBorder(new Color(0, 0, 0), 4, true));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 5;
gbc.gridwidth = 2;
gbc.gridheight = 2;
gbc.ipadx = 161;
gbc.ipady = 17;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(29, 65, 0, 0);
Cc.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Combo1.setModel(new DefaultComboBoxModel(CB1));
Combo2.setModel(new DefaultComboBoxModel(CB1));
Combo3.setModel(new DefaultComboBoxModel(CB1));
Combo4.setModel(new DefaultComboBoxModel(CB1));
Combo1.setSelectedIndex(0);
Combo2.setSelectedIndex(0);
Combo3.setSelectedIndex(0);
Combo4.setSelectedIndex(0);
}
});
P.add(Cc, gbc);
Pp.setFont(new Font("Tahoma", 3, 20));
Pp.setForeground(new Color(0, 204, 204));
Pp.setText("Pop");
Pp.setBorder(new javax.swing.border.LineBorder(new Color(0, 0, 0), 4, true));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 9;
gbc.gridwidth = 2;
gbc.ipadx = 191;
gbc.ipady = 17;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(16, 65, 0, 0);
Pp.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Combo1.setModel(new DefaultComboBoxModel(CB4));
Combo2.setModel(new DefaultComboBoxModel(CB4));
Combo3.setModel(new DefaultComboBoxModel(CB4));
Combo4.setModel(new DefaultComboBoxModel(CB4));
Combo1.setSelectedIndex(0);
Combo2.setSelectedIndex(0);
Combo3.setSelectedIndex(0);
Combo4.setSelectedIndex(0);
}
});
P.add(Pp, gbc);
Jz.setFont(new Font("Tahoma", 3, 20));
Jz.setForeground(new Color(0, 51, 153));
Jz.setText("Jazz");
Jz.setBorder(new javax.swing.border.LineBorder(new Color(0, 0, 0), 4, true));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 11;
gbc.gridwidth = 2;
gbc.ipadx = 185;
gbc.ipady = 17;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(12, 65, 0, 0);
Jz.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Combo1.setModel(new DefaultComboBoxModel(CB3));
Combo2.setModel(new DefaultComboBoxModel(CB3));
Combo3.setModel(new DefaultComboBoxModel(CB3));
Combo4.setModel(new DefaultComboBoxModel(CB3));
Combo1.setSelectedIndex(0);
Combo2.setSelectedIndex(0);
Combo3.setSelectedIndex(0);
Combo4.setSelectedIndex(0);
}
});
P.add(Jz, gbc);
Wn.setFont(new Font("Tahoma", 3, 20));
Wn.setForeground(new Color(0, 102, 102));
Wn.setText("Western");
Wn.setBorder(new javax.swing.border.LineBorder(new Color(0, 0, 0), 4, true));
gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 7;
gbc.gridwidth = 2;
gbc.ipadx = 145;
gbc.ipady = 17;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(18, 65, 0, 0);
Wn.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Combo1.setModel(new DefaultComboBoxModel(CB2));
Combo2.setModel(new DefaultComboBoxModel(CB2));
Combo3.setModel(new DefaultComboBoxModel(CB2));
Combo4.setModel(new DefaultComboBoxModel(CB2));
Combo1.setSelectedIndex(0);
Combo2.setSelectedIndex(0);
Combo3.setSelectedIndex(0);
Combo4.setSelectedIndex(0);
}
});
P.add(Wn, gbc);
Cart.setFont(new Font("Wide Latin", 1, 24));
Cart.setText("Add to Cart");
Cart.setBorder(new javax.swing.border.LineBorder(new Color(0, 0, 0), 5, true));
gbc = new GridBagConstraints();
gbc.gridx = 7;
gbc.gridy = 16;
gbc.gridwidth = 3;
gbc.gridheight = 2;
gbc.ipadx = 53;
gbc.ipady = 14;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(26, 75, 0, 0);
Cart.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent evt) {
AppletContext ac = getAppletContext();
URL url = getCodeBase(); // get url of this applet
try {
ac.showDocument(new URL(url+"Shopping_Cart.html"));
} catch(MalformedURLException e)
{
showStatus("URL not found");
}
}});
P.add(Cart, gbc);
Combo1.setBorder(javax.swing.BorderFactory.createMatteBorder(5, 5, 5, 5, new Color(0, 102, 204)));
Combo1.setPrototypeDisplayValue("XXXXXXXXXXXX");
gbc = new GridBagConstraints();
gbc.gridx = 6;
gbc.gridy = 5;
gbc.gridwidth = 0;
gbc.ipadx = 103;
gbc.ipady = 28;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(23, 17, 0, 0);
P.add(Combo1, gbc);
Combo2.setBorder(javax.swing.BorderFactory.createMatteBorder(5, 5, 5, 5, new Color(0, 204, 204)));
Combo2.setPrototypeDisplayValue("XXXXXXXXXXXX");
gbc = new GridBagConstraints();
gbc.gridx = 6;
gbc.gridy = 7;
gbc.gridwidth = 2;
gbc.gridheight = 2;
gbc.ipadx = 103;
gbc.ipady = 28;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(16, 17, 0, 0);
P.add(Combo2, gbc);
Combo3.setBorder(javax.swing.BorderFactory.createMatteBorder(5, 5, 5, 5, new Color(0, 153, 153)));
Combo3.setPrototypeDisplayValue("XXXXXXXXXXXX");
gbc = new GridBagConstraints();
gbc.gridx = 6;
gbc.gridy = 9;
gbc.gridwidth = 2;
gbc.gridheight = 2;
gbc.ipadx = 103;
gbc.ipady = 28;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(18, 17, 0, 0);
P.add(Combo3, gbc);
Combo4.setBorder(javax.swing.BorderFactory.createMatteBorder(5, 5, 5, 5, new Color(0, 0, 204)));
Combo4.setPrototypeDisplayValue("XXXXXXXXXXXX");
gbc = new GridBagConstraints();
gbc.gridx = 6;
gbc.gridy = 11;
gbc.gridwidth = 2;
gbc.gridheight = 2;
gbc.ipadx = 103;
gbc.ipady = 28;
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.insets = new Insets(18, 17, 0, 0);
P.add(Combo4, gbc);
GroupLayout layout = new GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(P, GroupLayout.PREFERRED_SIZE, 970, GroupLayout.PREFERRED_SIZE)
.addContainerGap()));
layout.setVerticalGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(P, GroupLayout.PREFERRED_SIZE, 700, GroupLayout.PREFERRED_SIZE)
.addGap(0, 68, Short.MAX_VALUE)));
}
}
答案 0 :(得分：5)
基本概念很简单。
我倾向于使用ItemListener，因为它对不同类型的选择输入更敏感，然后ActionListener
public class TestComboBox05 {
public static void main(String[] args) {
new TestComboBox05();
}
public TestComboBox05() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
final JLabel lbl = new JLabel();
add(lbl);
JComboBox cb = new JComboBox();
cb.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
if (e.getStateChange() == ItemEvent.SELECTED) {
lbl.setText(e.getItem().toString());
}
}
});
cb.addItem("1");
cb.addItem("2");
cb.addItem("3");
cb.addItem("4");
cb.addItem("5");
add(cb);
}
}
}
基本上，当触发itemStateChanged事件时，您需要找到所选项目并相应地更改标签的图标。此示例显示更改文本，但概念是相同的。
答案 1 :(得分：3)
这是伪代码。
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class ChangeJlableByJComboBox extends JFrame {
private static final long serialVersionUID = 1L;
public ChangeJlableByJComboBox() {
super("TooltipInSwing");
setSize(400, 300);
getContentPane().setLayout(new FlowLayout());
final JLabel b1;
final JComboBox jb1 = new JComboBox(new String[] { " ", "one", "two",
"three" });
b1 = new JLabel("Default Lable");
getContentPane().add(b1);
getContentPane().add(jb1);
jb1.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// setting custom text to JLabel
if (jb1.getSelectedItem().toString().equals("one"))
b1.setText("Lable one ---");
else if (jb1.getSelectedItem().toString().equals("two"))
b1.setText("Lable two ---");
else if (jb1.getSelectedItem().toString().equals("three"))
b1.setText("Lable three ---");
else
b1.setText("----");
// or Compact version for setting JcomboBox selected item
// to JLabel text
// b1.setText(jb1.getSelectedItem().toString());
System.out.println(jb1.getSelectedItem().toString());
// you can also make use of following method
System.out.println(jb1.getSelectedIndex());
}
});
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
setVisible(true);
}
public static void main(String args[]) {
new ChangeJlableByJComboBox();
}
}
我希望这可以帮助您解决问题。