我在Jframe中遇到此问题。我使用JComboBox来显示用户的一些选择（来自日期库），他选择了一个选项，然后在重新运行initComponents()后，我想排除这个选择并仅显示其余部分。但是对于某些人来说原因无论我如何编辑代码，它一直显示相同。有什么建议？ Thx提前（随时问我什么）。
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
DefaultComboBoxModel m=new DefaultComboBoxModel();//this is the m which is //displayed by the combobox
try//try to connect to database
{
Connection conn=new DBconnect().con();
Statement stmt=new DBconnect().stm(conn);
final ResultSet rs = stmt.executeQuery( "SELECT * FROM BILL WHERE CUSTOMER_CODE="+login.password+" AND BILL_TYPE='contract'") ;//get the data from sql
m.removeAllElements();
while(rs.next()){//get the date to string
String nbill=(rs.getString("telephone")+" Program:"+rs.getString("programm")+" Remaind Free Time:"+rs.getString("remaind_free_time"));
//The user selects the telephone (tel) and then rerunning the INitComponents here we test
if(rs.getString("telephone").equals(tel)){
System.out.println("ok");
m.removeElement(nbill);
//I putted continue here instead else here but the same
}
else{
m.addElement(nbill);
}
}
}
}
的 的 ** * ** * ** * 的** * （这是整个代码） * ** * ** * ** * ** * ** * ** * **** @SuppressWarnings（ “未登记”）
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
DefaultComboBoxModel m=new DefaultComboBoxModel();
try
{
Connection conn=new DBconnect().con();
Statement stmt=new DBconnect().stm(conn);
final ResultSet rs = stmt.executeQuery( "SELECT * FROM BILL WHERE CUSTOMER_CODE="+login.password+" AND BILL_TYPE='contract'") ;
//erase stuff not needed
m.removeAllElements();
while(rs.next()){
String nbill=(rs.getString("telephone")+" Program:"+rs.getString("programm")+" Remaind Free Time:"+rs.getString("remaind_free_time"));
if(rs.getString("telephone").equals(tel)){
System.out.println("ok");
m.removeElement(nbill);
}
else{
m.addElement(nbill);
}
}
/* for(String nbill : m){
if(nbill.substring(0,10).equals(tel)){
m.removeElement(nbill);}
}*/
jComboBox1 = new javax.swing.JComboBox();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Επιλέξτε το Συμβόλαιο από το οποίο επιθυμείτε να πάρετε χρόνο");
jComboBox1.setModel(m);
jComboBox1.addKeyListener(new java.awt.event.KeyAdapter() {
public void keyPressed(java.awt.event.KeyEvent evt) {
jComboBox1KeyPressed(evt);
}
});
}
catch( SQLException se )
{
System.out.println( "SQL Exception:" ) ;
// Loop through the SQL Exceptions
while( se != null )
{
System.out.println( "State : " + se.getSQLState() ) ;
System.out.println( "Message: " + se.getMessage() ) ;
System.out.println( "Error : " + se.getErrorCode() ) ;
se = se.getNextException() ;
}
}
catch( Exception e )
{
System.out.println( e ) ;
}
jLabel2.setText("Ή esc για επιστροφή στο κεντρικό menu");
jLabel3.setText("και πατήστε enter");
jLabel4.setText("(Η μεταφορά χρόνου ισχυεί για όμοια πργ.)");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(40, 40, 40)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 343, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(52, 52, 52)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel3)
.addGap(18, 18, 18)
.addComponent(jLabel4, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel2)
.addComponent(jLabel1)))))
.addContainerGap(42, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addComponent(jLabel1)
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(jLabel4))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, 35, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 182, Short.MAX_VALUE)
.addComponent(jLabel2)
.addGap(26, 26, 26))
);
pack();
}// </editor-fold>
private void jComboBox1KeyPressed(java.awt.event.KeyEvent evt) {
if(evt.getKeyCode()==evt.VK_ENTER){
if("0".equals(login.password.substring(0,1))){
this.setVisible(false);
// choose_option_man of = new choose_option_man();
//of.setVisible(true);
}
else if("1".equals(login.password.substring(0,1))){
//if(ξεκινάει από 0 ή 1....)
this.setVisible(false);
// choose_option_company of = new choose_option_company();
// of.setVisible(true);
}
if(jComboBox1.getSelectedItem()!=null){
String choice=(String) jComboBox1.getSelectedItem();
//int i = choice.lastIndexOf(":");
tel = choice.substring(0,10);//telephone fetched
//ok System.out.println("telephone"+tel);
String FreeTime = choice.substring(41,44);
int FreeTimeN = Integer.parseInt(FreeTime);//remaining free time fetched
//ok System.out.println("NUmber"+FreeTimeN);
/* this.setVisible(false);
TransferInput of = new TransferInput();///with another Jframe
of.setVisible(true);*/
/* JTextField new_text = new JTextField("Test text");
JDialog new_dialog = new JDialog(Test_Contracts, "Test");
new_dialog.pack();
new_dialog.setVisible(true);
new_dialog.toFront();
new_dialog.setSize(500,150);
new_dialog.setLocation(500,500);
new_dialog.add(new_text); */
String TimeTransfer = JOptionPane.showInputDialog ( "Βάλτε το χρόνο" ); //put here Time for transfer
int TimeTransferN = Integer.parseInt(TimeTransfer);
if(TimeTransferN>FreeTimeN){
JOptionPane.showMessageDialog(null,"Ανεπιτυχής συναλλαγή χρόνου!", "Inane error",JOptionPane.ERROR_MESSAGE);//αντι null frame???
//get back to main menu with visible
}
else{
//xXx=true;
initComponents();
this.setVisible(true);
}
}
}
else if(evt.getKeyCode()==evt.VK_ESCAPE){
if("0".equals(login.password.substring(0,1))){
this.setVisible(false);
choose_option_man of = new choose_option_man();
of.setVisible(true);
}
else if("1".equals(login.password.substring(0,1))){
//if(ξεκινάει από 0 ή 1....)
this.setVisible(false);
choose_option_company of = new choose_option_company();
of.setVisible(true);
}
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Test_Contracts.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Test_Contracts.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Test_Contracts.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Test_Contracts.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Test_Contracts().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JComboBox jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
// End of variables declaration
}
答案 0 :(得分：2)
//this is the m which is displayed by the combobox
DefaultComboBoxModel m=new DefaultComboBoxModel();
不，它不是组合框显示的模型。它是模型的新创建的本地实例。您永远不会将此模型实例添加到组合框中。
假设您已在代码中的某处定义了名为“m”的类变量，则无需创建新模型。只需清除现有模型，然后添加数据库查询中的元素即可。
编辑：
在您发布部分代码之前。您现在添加了更多代码，我看到了以下几行：
jComboBox1 = new javax.swing.JComboBox();
...
jComboBox1.setModel(m);
现在你创建一个新的comboBox并将模型添加到它。
问题是您没有将新创建的comboBox添加到框架中，因此您永远不会看到更新。更新变量的引用与将组件添加到框架不同。
您需要删除创建新comboBox的行，或者需要将新的comboBox添加到框架中。
将来发布问题时，您需要发布一个SSCCE来证明您的问题。