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我有一個使用JCombobox的java窗體。有一個「文本字段」，「組合框」和「添加」按鈕。當我在文本字段中輸入文本時，然後單擊添加按鈕，文本字段中的文本將填充到組合框中，但不會按a-z排序。如何在java中對項目進行排序combobox
下面是我在添加按鈕的代碼。
private void cmdAddActionPerformed(java.awt.event.ActionEvent evt) {
if(MyInput.checkText(txtField)){ //MyInput is my own method code to check if the text is entered.
String st=txtField.getText();
combox.addItem(st);
String st1="";
String st2="";
int com=st1.compareTo(st2);
if(com<0){ //I create this string comparison
//I need to add the "sort" code here
}else{
}
}else
JOptionPane.showMessageDialog(this, "Please enter text."); //When no text is entered, this message appears.
}
完整的源代碼：
import PlugIn.MyInput;
import javax.swing.JOptionPane;
public class JCombo extends javax.swing.JFrame {
/**
* Creates new form JCombo
*/
public JCombo() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
txt = new javax.swing.JTextField();
combo = new javax.swing.JComboBox();
cmdAdd = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
txt.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
txtActionPerformed(evt);
}
});
combo.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
comboActionPerformed(evt);
}
});
cmdAdd.setText("Add");
cmdAdd.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
cmdAddActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(88, 88, 88)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(txt)
.addComponent(combo, 0, 188, Short.MAX_VALUE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(cmdAdd)
.addContainerGap(63, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(40, 40, 40)
.addComponent(txt, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(combo, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(cmdAdd))
.addContainerGap(206, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void txtActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void cmdAddActionPerformed(java.awt.event.ActionEvent evt) {
if(MyInput.checkText(txtField)){ //MyInput is my own method code to check if the text is entered.
String st=txtField.getText();
combox.addItem(st);
String st1="";
String st2="";
int com=st1.compareTo(st2);
if(com<0){ //I create this string comparison
//I need to add the "sort" code here
}else{
}
}else
JOptionPane.showMessageDialog(this, "Please enter text."); //When no text is entered, this message appears.
}
private void comboActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
/**
* @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(JCombo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(JCombo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(JCombo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(JCombo.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 JCombo().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton cmdAdd;
private javax.swing.JComboBox combo;
private javax.swing.JTextField txt;
// End of variables declaration
}