我知道我错过了一些简单的东西，我认为让组合框访问数组。
package my.freelancebillingapp;
import java.sql.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.ArrayList;
import javax.swing.*;
public class billingInfoUI extends javax.swing.JFrame {
public billingInfoUI() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jPanel1 = new javax.swing.JPanel();
hoursWorked = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
flatRate = new javax.swing.JTextField();
jScrollPane1 = new javax.swing.JScrollPane();
workType = new javax.swing.JList();
jScrollPane2 = new javax.swing.JScrollPane();
jList2 = new javax.swing.JList();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
jComboBox1 = new javax.swing.JComboBox();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jPanel1.setBorder(javax.swing.BorderFactory.createTitledBorder(null, "Billing Information", javax.swing.border.TitledBorder.CENTER, javax.swing.border.TitledBorder.ABOVE_BOTTOM, new java.awt.Font("Bleeding Cowboys", 0, 48))); // NOI18N
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 457, Short.MAX_VALUE)
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 0, Short.MAX_VALUE)
);
hoursWorked.setHorizontalAlignment(javax.swing.JTextField.CENTER);
hoursWorked.setText("Hours Worked");
hoursWorked.setBorder(null);
jLabel1.setText("Or");
flatRate.setHorizontalAlignment(javax.swing.JTextField.CENTER);
flatRate.setText("Flat Rate");
flatRate.setBorder(null);
workType.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createEtchedBorder(), "Work Type", javax.swing.border.TitledBorder.CENTER, javax.swing.border.TitledBorder.TOP));
workType.setModel(new javax.swing.AbstractListModel() {
String[] strings = { "Web Design", "Graphic Design", "Consulting" };
public int getSize() { return strings.length; }
public Object getElementAt(int i) { return strings[i]; }
});
workType.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
jScrollPane1.setViewportView(workType);
jList2.setBorder(javax.swing.BorderFactory.createTitledBorder(javax.swing.BorderFactory.createEtchedBorder(), "Any Extras?", javax.swing.border.TitledBorder.CENTER, javax.swing.border.TitledBorder.TOP));
jList2.setModel(new javax.swing.AbstractListModel() {
String[] strings = { "Blog", "Forum", "Templating", "Rush Delivery" };
public int getSize() { return strings.length; }
public Object getElementAt(int i) { return strings[i]; }
});
jScrollPane2.setViewportView(jList2);
jButton1.setText("Save");
jButton1.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jButton1MouseClicked(evt);
}
});
jButton2.setText("Invoice");
jButton3.setText("Close");
jButton3.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
jButton3MouseClicked(evt);
}
});
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
jComboBox1.setModel(customers);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(89, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(hoursWorked, javax.swing.GroupLayout.PREFERRED_SIZE, 83, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(48, 48, 48)
.addComponent(jLabel1)
.addGap(1, 1, 1))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 142, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(31, 31, 31)))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(18, 18, 18)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(49, 49, 49)
.addComponent(flatRate, javax.swing.GroupLayout.PREFERRED_SIZE, 56, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(79, 79, 79))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(62, 62, 62)
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 103, Short.MAX_VALUE)
.addComponent(jButton2)
.addGap(79, 79, 79)
.addComponent(jButton3)
.addGap(52, 52, 52))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(134, Short.MAX_VALUE)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 238, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(107, 107, 107))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(30, 30, 30)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(hoursWorked, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(flatRate, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1))
.addGap(20, 20, 20)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 86, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 40, Short.MAX_VALUE)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(51, 51, 51)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton2)
.addComponent(jButton3)
.addComponent(jButton1))
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jButton3MouseClicked(java.awt.event.MouseEvent evt) {
new FreelanceBillingUI().setVisible(true);
setVisible(false);
}
private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {
String hoursWorkedtxt = hoursWorked.getText();
String flatRatetxt = flatRate.getText();
workType.getSelectedValue();
workType.toString();
Object workTypetxt = workType.getSelectedValue();
if(hoursWorkedtxt.contains("H")){
hoursWorkedtxt = "0";
}else{
flatRatetxt = "0";
}
}
public class CustomerData {
private static final String JDBC_CONNECTION_URL = "jdbc:mysql://localhost/test";
private static final String DATABASE_USER = "root";
private static final String DATABASE_PASSWORD = "root";
private static final String SQL_FETCH_CUSTOMERS = "SELECT custName FROM customers";
private Connection connection = null;
public CustomerData(){
initConnection();
}
private void initConnection() {
try {
//load the mysql driver
Class.forName("com.mysql.jdbc.Driver");
//create the database connection
connection = DriverManager.getConnection(JDBC_CONNECTION_URL, DATABASE_USER, DATABASE_PASSWORD);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
public void closeConnection(){
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
connection = null;
}
}
}
public ArrayList fetchCustomerData(){
if (connection != null){
Statement statement = null;
try {
statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(SQL_FETCH_CUSTOMERS);
return convertResultSetToCustomersArray(resultSet);
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (statement != null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}else{
System.out.println("NO VALID DATABASE CONNECTION, CAN'T FETCH CUSTOMER DATA!");
}
return new ArrayList();
}
private ArrayList convertResultSetToCustomersArray(ResultSet results) throws SQLException{
ArrayList customers = new ArrayList();
while (results.next()){
customers.add(results.getString("custName"));
}
return customers;
}
}
private void initData(){
CustomerData customerData = new CustomerData();
ArrayList custArrayList = customerData.fetchCustomerData();
customers = (String[]) custArrayList.toArray(new String[0]);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new billingInfoUI().setVisible(true);
}
});
}
private String[] customers = null;
private javax.swing.JTextField flatRate;
private javax.swing.JTextField hoursWorked;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JComboBox jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JList jList2;
private javax.swing.JPanel jPanel1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JScrollPane jScrollPane2;
private javax.swing.JList workType;
}
答案 0 :(得分：5)
有太多代码可供查看，其中90％与在组合框中添加数据无关。你有十几个其他组件使代码混乱，所以我们无法看到comobo框实际发生了什么。
您真的需要帮助，然后发布SSCCE。
即创建一个简单的框架并将硬编码数据加载到组合框中。
然后创建一个简单的程序来从数据库中读取数据，并使用System.out.println（...）来显示每个值。
一旦掌握了两个基本步骤，就将两个程序放在一起，从数据库中动态加载组合框。
最后将其余的组件添加到框架中。
将问题分解为小的，可管理的步骤，您将能够更轻松地调试它。
答案 1 :(得分：1)
几点：
initData的电话。没有那个调用，你就不会调用你的数据库代码。没有数据库调用，您将无法获取数据。JComboBox没有采用数组的setModel方法。您可以将数组包装在DefaultComboBoxModel中并在模型上进行设置。 SwingUtlities.invokeLater或类似工具来更新GUI。