Java.swing.ComboBox Düğme sınıfında kullanılamazExException

Question

Bazı nedenler ComboBox'ımın düğme üzerinde neden yer aldığını bilmiyorum. Lütfen yardım:

Kodu:

import java.awt.GridBagLayout; 
import java.awt.GridLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 

import javax.swing.*; 


public class LocalBank implements ActionListener { 

    JFrame frame; 
    JPanel contentPane; 
    JLabel label1; 
    JLabel label2; 
    JLabel label3; 
    JTextField accNumber; 
    JTextField withdraw; 
    JTextField text3; 
    JButton avgButton; 
    JLabel average; 
    JComboBox plantNames; 
    JTextField firstname; 
    JTextField lastname; 
    JTextField beggining; 
    JButton submit; 
    JLabel accNumLabel; 
    JLabel withdawLabel; 
    JLabel firstnameLabel; 
    JLabel lastnameLabel; 
    JLabel begginingLabel; 

    public LocalBank() { 
    // TODO Auto-generated constructor stub 
    frame = new JFrame("Semiseter"); 


    contentPane = new JPanel(); 
    contentPane.setLayout(new BoxLayout(contentPane,BoxLayout.PAGE_AXIS)); 
    contentPane.setBorder(BorderFactory.createEmptyBorder 
     (20, 20, 20, 20)); 


    label1 = new JLabel("Enter An Integer"); 
    label1.setAlignmentX(JLabel.LEFT_ALIGNMENT); 
    contentPane.add(label1); 


    String[] names = {"Deposit", "Withdrawal", "Check Balance","Add Account","Remove Account"}; 
    plantNames = new JComboBox(names); 
    plantNames.setAlignmentX(JComboBox.LEFT_ALIGNMENT); 
    plantNames.setSelectedIndex(0); 
    plantNames.addActionListener(this); 
    contentPane.add(plantNames); 

    accNumLabel = new JLabel("Account Number"); 
    contentPane.add(accNumLabel); 
    accNumber = new JTextField(); 
    contentPane.add(accNumber); 

    withdawLabel = new JLabel("Amount of deposit/withdrawal:"); 
    contentPane.add(withdawLabel); 

    withdraw = new JTextField(""); 
    contentPane.add(withdraw); 

    firstnameLabel = new JLabel("First Name:"); 
    contentPane.add(firstnameLabel); 

    firstname = new JTextField(); 
    contentPane.add(firstname); 

    lastnameLabel = new JLabel("Last Name:"); 
    contentPane.add(lastnameLabel); 

    lastname = new JTextField(""); 
    contentPane.add(lastname); 

    begginingLabel = new JLabel("Beginning Balance:"); 
    contentPane.add(begginingLabel); 

    beggining = new JTextField(""); 
    contentPane.add(beggining); 

    submit = new JButton("Process Transaction"); 
    submit.addActionListener(this); 
    submit.setActionCommand("Submit"); 
    contentPane.add(submit); 

    frame.setContentPane(contentPane); 

     /* Size and then display the frame. */ 
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    frame.pack(); 
    frame.setVisible(true); 



    } 



    private static void runGUI() { 
    JFrame.setDefaultLookAndFeelDecorated(true); 
    LocalBank greeting = new LocalBank(); 
    } 
    public static void main(String[] args) { 
     /* Methods that create and show a GUI should be 
     run from an event-dispatching thread */ 
    javax.swing.SwingUtilities.invokeLater(new Runnable() { 
     public void run() { 
     runGUI(); 
     } 
    }); 


    } 



    public void actionPerformed(ActionEvent event) { 
    // TODO Auto-generated method stub 
    JComboBox comboBox = (JComboBox)event.getSource(); 
    String plantName = (String)comboBox.getSelectedItem(); 
    String eventString = event.getActionCommand(); 
    if (plantName == "Deposit") { 
     accNumLabel.setVisible(true); 
     accNumber.setVisible(true); 

     withdawLabel.setVisible(true); 
     withdraw.setVisible(true); 

     firstnameLabel.setVisible(false); 
     firstname.setVisible(false); 

     lastnameLabel.setVisible(false); 
     lastname.setVisible(false); 

     begginingLabel.setVisible(false); 
     beggining.setVisible(false); 

     if(eventString.equals("Submit")){ 
      System.out.println("Person with account number " + accNumLabel.getText().toString() + " Withdraws $" + withdawLabel.getText().toString()); 
     } 
    } 
    else if (plantName == "Withdrawal") { 
     accNumLabel.setVisible(true); 
     accNumber.setVisible(true); 

     withdawLabel.setVisible(true); 
     withdraw.setVisible(true); 

     firstnameLabel.setVisible(false); 
     firstname.setVisible(false); 

     lastnameLabel.setVisible(false); 
     lastname.setVisible(false); 

     begginingLabel.setVisible(false); 
     beggining.setVisible(false); 
    } 
    else if (plantName == "Check Balance") { 

     accNumLabel.setVisible(true); 
     accNumber.setVisible(true); 

     firstnameLabel.setVisible(false); 
     firstname.setVisible(false); 

     lastnameLabel.setVisible(false); 
     lastname.setVisible(false); 

     begginingLabel.setVisible(false); 
     beggining.setVisible(false); 

     withdawLabel.setVisible(false); 
     withdraw.setVisible(false); 
    } 
    else if (plantName == "Add Account") { 
     accNumLabel.setVisible(false); 
     accNumber.setVisible(false); 

     withdawLabel.setVisible(false); 
     withdraw.setVisible(false); 

     firstnameLabel.setVisible(true); 
     firstname.setVisible(true); 

     lastnameLabel.setVisible(true); 
     lastname.setVisible(true); 

     begginingLabel.setVisible(true); 
     beggining.setVisible(true); 
    } 
    else if (plantName == "Remove Account") { 
     accNumLabel.setVisible(true); 
     accNumber.setVisible(true); 

     withdawLabel.setVisible(false); 
     withdraw.setVisible(false); 

     firstnameLabel.setVisible(false); 
     firstname.setVisible(false); 

     lastnameLabel.setVisible(false); 
     lastname.setVisible(false); 

     begginingLabel.setVisible(false); 
     beggining.setVisible(false); 
    } 
    else{ 
     accNumLabel.setVisible(false); 
     accNumber.setVisible(false); 

     withdawLabel.setVisible(false); 
     withdraw.setVisible(false); 

     firstnameLabel.setVisible(false); 
     firstname.setVisible(false); 

     lastnameLabel.setVisible(false); 
     lastname.setVisible(false); 

     begginingLabel.setVisible(false); 
     beggining.setVisible(false); 
    } 
    } 
} 

Hata: hem sen bileşenlere

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JButton cannot be cast to javax.swing.JComboBox at LocalBank.actionPerformed(LocalBank.java:124) at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) at javax.swing.DefaultButtonModel.setPressed(Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) at java.awt.Component.processMouseEvent(Unknown Source) at javax.swing.JComponent.processMouseEvent(Unknown Source) at java.awt.Component.processEvent(Unknown Source) at java.awt.Container.processEvent(Unknown Source) at java.awt.Component.dispatchEventImpl(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) at java.awt.Container.dispatchEventImpl(Unknown Source) at java.awt.Window.dispatchEventImpl(Unknown Source) at java.awt.Component.dispatchEvent(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$400(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue$4.run(Unknown Source) at java.awt.EventQueue$4.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

eklediniz ActionListseners: Düğme, Ve JComboBox.

Yani,

• değişiklik JComboBox oluşursa, kodunuz çalışıyor.
Ama butonuna tıklandığında, ComboBox

Ben bunun yerine bir Eylem Listener, sizin açılan kutunun bir ItemListener eklemek önermek değil Düğme, hiç event.getSource() puan (this bakın ve this link about ItemListener)