我遇到的问题是给我一条错误消息，并且出现了一个空白小程序。错误消息显示load：class Myapp.class not found and java.lang.ClassNotFoundException，然后是一行代表@和其他一些行话。
如果我运行尝试将程序作为Jcreator applet运行，就像我预期的那样我得到了先前声明的错误，如果我在应用程序中运行它，它只是给我主要的方法错误。
这是我的计划：
package MyPack;
import javax.swing.*;
import java.awt.event.*;
public class Myapp extends JApplet implements ItemListener{
JButton jbtnOne;
JButton jbtnTwo;
JLabel jlab;
JComboBox comboBox;
JComboBox comboBox_1;
JCheckBox chckbxPizza;
JCheckBox chckbxBurger;
JCheckBox chckbxSalad;
JLabel label_3;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
JTextArea txtrCommentsForSpecial;
JTextArea txtrCommentsForSpecial_2;
JTextArea txtrCommentsForSpecial_1;
JInternalFrame internalFrame;
public Myapp() {
}
public void init() {
setSize(700,640);
// setVisible(true);
try {
SwingUtilities.invokeAndWait(new Runnable () {
public void run() {
guiInit(); // initialize the GUI
}
});
} catch(Exception exc) {
System.out.println("Can't create because of "+ exc);
}
}
// Called second, after init(). Also called
// whenever the applet is restarted.
public void start() {
// Not used by this applet.
}
// Called when the applet is stopped.
public void stop() {
// Not used by this applet.
}
// Called when applet is terminated. This is
// the last method executed.
public void destroy() {
// Not used by this applet.
}
// Setup and initialize the GUI.
private void guiInit() {
// Create two buttons and a label.
// setLayout(null);
String a[] = { "Chiken Tikka", "Fajita", "Vegetable"};
comboBox = new JComboBox(a);
comboBox.setBounds(115, 103, 100, 20);
comboBox.addItemListener(this);
getContentPane().add(comboBox);
String b[] = { "small", "medium","large","extra large"};
comboBox_1 = new JComboBox(b);
// comboBox_1.addItemListener(this);
// comboBox_1.setEnabled(false);
getContentPane().add(comboBox_1);
comboBox_1.setBounds(290, 103, 140, 20);
// setSize(300, 300);
getContentPane().setLayout(null);
JLabel lblSelectMenu = new JLabel("Select Menu");
lblSelectMenu.setForeground(new Color(72, 61, 139));
lblSelectMenu.setFont(new Font("Segoe Script", Font.BOLD, 16));
lblSelectMenu.setBounds(58, 10, 107, 34);
getContentPane().add(lblSelectMenu);
chckbxPizza = new JCheckBox("Pizza");
chckbxPizza.setBounds(37, 64, 97, 23);
getContentPane().add(chckbxPizza);
JLabel lblFlavour = new JLabel("flavour");
lblFlavour.setBounds(60, 103, 45, 20);
getContentPane().add(lblFlavour);
JLabel lblSize = new JLabel("size");
lblSize.setBounds(253, 103, 45, 20);
getContentPane().add(lblSize);
JLabel lblQty = new JLabel("Qty");
lblQty.setBounds(451, 103, 35, 20);
getContentPane().add(lblQty);
textField = new JTextField();
textField.setBounds(485, 103, 86, 20);
getContentPane().add(textField);
textField.setColumns(10);
JLabel lblComments = new JLabel("comments");
lblComments.setBounds(139, 154, 76, 20);
getContentPane().add(lblComments);
txtrCommentsForSpecial = new JTextArea();
txtrCommentsForSpecial.setForeground(new Color(220, 220, 220));
txtrCommentsForSpecial.setText("comments for special features");
txtrCommentsForSpecial.setBounds(210, 154, 268, 61);
getContentPane().add(txtrCommentsForSpecial);
chckbxBurger = new JCheckBox("Burger");
chckbxBurger.setBounds(37, 236, 97, 23);
getContentPane().add(chckbxBurger);
JLabel label = new JLabel("flavour");
label.setBounds(60, 286, 45, 20);
getContentPane().add(label);
String c[] = { "Fish", "Vegetable", "Chicken"};
JComboBox comboBox_2 = new JComboBox(c);
comboBox_2.setBounds(115, 286, 100, 20);
getContentPane().add(comboBox_2);
JLabel label_1 = new JLabel("size");
label_1.setBounds(253, 286, 45, 20);
getContentPane().add(label_1);
JComboBox comboBox_3 = new JComboBox(b);
comboBox_3.setBounds(290, 286, 110, 20);
getContentPane().add(comboBox_3);
JLabel label_2 = new JLabel("Qty");
label_2.setBounds(451, 286, 35, 20);
getContentPane().add(label_2);
textField_1 = new JTextField();
textField_1.setBounds(485, 286, 86, 20);
getContentPane().add(textField_1);
textField_1.setColumns(10);
label_3 = new JLabel("comments");
label_3.setBounds(139, 340, 76, 20);
getContentPane().add(label_3);
txtrCommentsForSpecial_1 = new JTextArea();
txtrCommentsForSpecial_1.setForeground(new Color(220, 220, 220));
txtrCommentsForSpecial_1.setText("comments for special features");
txtrCommentsForSpecial_1.setBounds(210, 340, 268, 61);
getContentPane().add(txtrCommentsForSpecial_1);
chckbxSalad = new JCheckBox("Soft Drink");
chckbxSalad.setBounds(37, 424, 97, 23);
getContentPane().add(chckbxSalad);
JLabel label_4 = new JLabel("flavour");
label_4.setBounds(60, 475, 45, 20);
getContentPane().add(label_4);
String f[] = { "Pepsi", "Coca Cola", "Sprite","7up"};
JComboBox comboBox_4 = new JComboBox(f);
comboBox_4.setBounds(115, 475, 86, 20);
getContentPane().add(comboBox_4);
JLabel label_5 = new JLabel("size");
label_5.setBounds(253, 475, 45, 20);
getContentPane().add(label_5);
JComboBox comboBox_5 = new JComboBox(b);
comboBox_5.setBounds(290, 475, 110, 20);
getContentPane().add(comboBox_5);
JLabel label_6 = new JLabel("Qty");
label_6.setBounds(451, 475, 35, 20);
getContentPane().add(label_6);
textField_2 = new JTextField();
textField_2.setBounds(485, 475, 86, 20);
getContentPane().add(textField_2);
textField_2.setColumns(10);
JLabel label_7 = new JLabel("comments");
label_7.setBounds(139, 546, 76, 20);
getContentPane().add(label_7);
txtrCommentsForSpecial_2 = new JTextArea();
txtrCommentsForSpecial_2.setForeground(new Color(220, 220, 220));
txtrCommentsForSpecial_2.setText("comments for special features");
txtrCommentsForSpecial_2.setBounds(210, 546, 268, 61);
getContentPane().add(txtrCommentsForSpecial_2);
JButton btnNewButton = new JButton("Ok");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
internalFrame = new JInternalFrame("Order Details");
internalFrame.setBounds(100, 80, 450, 300);
internalFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
internalFrame.getContentPane().setLayout(null);
internalFrame.setVisible(true);
JTextArea textArea = new JTextArea();
textArea.setBounds(67, 52, 270, 149);
internalFrame.getContentPane().add(textArea);
JButton btnOk = new JButton("Ok");
btnOk.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
internalFrame.setVisible(false);
}
});
btnOk.setBounds(164, 212, 89, 23);
internalFrame.getContentPane().add(btnOk);
JLabel lblOrderYouPlaced = new JLabel("Order You Placed");
lblOrderYouPlaced.setBounds(67, 26, 98, 14);
internalFrame.getContentPane().add(lblOrderYouPlaced);
getContentPane().add(internalFrame);
}
});
btnNewButton.setBounds(162, 616, 89, 23);
getContentPane().add(btnNewButton);
JButton btnNewButton_1 = new JButton("Reset");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
textField.setText("");
textField_1.setText("");
textField_2.setText("");
chckbxPizza.setText("");
chckbxBurger.setText("");
chckbxSalad.setText("");
txtrCommentsForSpecial.setText("");
txtrCommentsForSpecial_2.setText("");
txtrCommentsForSpecial_1.setText("");
}
});
btnNewButton_1.setBounds(279, 616, 89, 23);
getContentPane().add(btnNewButton_1);
JButton btnNewButton_2 = new JButton("Cancel");
btnNewButton_2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
btnNewButton_2.setBounds(389, 616, 89, 23);
getContentPane().add(btnNewButton_2);
}
public void itemStateChanged(ItemEvent e) {
String b[] = { "Chikken Tikka", "Fajita" };
String c[] = { "Fish", "Vegetable", "Chicken"};
String d[] = { "Russian Salad", "Fruit Salad", "Beans Salad"};
String f[] = { "Pepsi", "Coca Cola", "Sprite","7up"};
if (e.getSource() == comboBox) {
if (comboBox.getSelectedItem().equals("Select")) {
comboBox_1.setEnabled(false);
} else if (comboBox.getSelectedItem().equals("Pizza")) {
comboBox_1.setEnabled(true);
comboBox_1.removeAllItems();
for (int i = 0; i < b.length; i++) {
comboBox_1.addItem(b[i]);
}
} else if (comboBox.getSelectedItem().equals("Burger")) {
comboBox_1.setEnabled(true);
comboBox_1.removeAllItems();
for (int i = 0; i < c.length; i++) {
comboBox_1.removeItem(c[i]);
comboBox_1.addItem(c[i]);
}
} else if (comboBox.getSelectedItem().equals("Salad")) {
comboBox_1.setEnabled(true);
comboBox_1.removeAllItems();
for (int i = 0; i < d.length; i++) {
comboBox_1.addItem(d[i]);
}
}else if (comboBox.getSelectedItem().equals("Soft Drink")) {
comboBox_1.setEnabled(true);
comboBox_1.removeAllItems();
for (int i = 0; i < f.length; i++) {
comboBox_1.addItem(f[i]);
}
}
}
}
}
答案 0 :(得分：0)
使用大写字母（例如
）编写itemListener public class Myapp extends JApplet implements ItemListener{
并导入所有这些包：
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;