为什么JFormattedTextField不支持actionPerformed

Question

I have a JFormattedTextField in my form, and i wish that after entering value when user presses enters it should move to next field. But after my all tries I am failed to do so. To achieve this I have attached an ActionListener to JFormattedTextField but pressing of Enter never trigger event. Why? can anybody help?

public class Test extends javax.swing.JFrame {

    /**
     * Creates new form Test
     */
    public Test() {
        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() {

        ftf = new javax.swing.JFormattedTextField();
        jLabel1 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        ftf.setFormatterFactory(new javax.swing.text.DefaultFormatterFactory(new javax.swing.text.NumberFormatter(new java.text.DecimalFormat("#0.00"))));
        ftf.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                ftfActionPerformed(evt);
            }
        });

        jLabel1.setText("JFormattedTextField Action Test");

        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(38, 38, 38)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(ftf, javax.swing.GroupLayout.PREFERRED_SIZE, 156, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 195, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(167, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(10, 10, 10)
                .addComponent(jLabel1)
                .addGap(18, 18, 18)
                .addComponent(ftf, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(238, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void ftfActionPerformed(java.awt.event.ActionEvent evt) {                                    
        // TODO add your handling code here:
        JOptionPane.showMessageDialog(this, "Enter Pressed");
    }                                   

    /**
     * @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.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Test.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Test.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Test.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().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JFormattedTextField ftf;
    private javax.swing.JLabel jLabel1;
    // End of variables declaration                   
}

Answer 1

You need to add an Action :

Action action = new AbstractAction()
{
    @Override
    public void actionPerformed(ActionEvent e)
    {
        //preform your action here.
    }
};


ftf.addActionListener( action );

And the action is executed when enter key is pressed.

Answer 2

You can do it by either way.

1. There is a simple trick for this. After you constructed the frame with all it buttons do this:

frame.getRootPane().setDefaultButton(submitButton);

For each frame, you can set a default button that will automatically listen to the Enter key (and maybe some other event's I'm not aware of). When you hit enter in that frame, the ActionListeners their actionPerformed() method will be invoked.

2. A JFormattedTextField was designed to use an ActionListener just like a JButton is. See the addActionListener() method of JFormattedTextField.

For example:

Action action = new AbstractAction()
{
    @Override
    public void actionPerformed(ActionEvent e)
    {
        System.out.println("some action");
    }
};

JFormattedTextField textField = new JFormattedTextField(10);
textField.addActionListener( action );

Now the event is fired when the Enter key is used.

Also, an added benefit is that you can share the listener with a button even if you don't want to make the button a default button.

JButton button = new JButton("Do Something");
button.addActionListener( action );

Note, this example uses an Action, which implements ActionListener because Action is a newer API with addition features. For example you could disable the Action which would disable the event for both the text field and the button.

Answer 3

Instead of ActionListener you can bind Enter key to JFormattedTextField and call AbstractAction when Enter is pressed:

InputMap inputMap = ftf.getInputMap(JComponent.WHEN_FOCUSED);
        inputMap.put(KeyStroke.getKeyStroke((char) KeyEvent.VK_ENTER), "enterPressed");
        ftf.getActionMap().put("enterPressed", new AbstractAction() {

            @Override
            public void actionPerformed(ActionEvent e) {
                System.out.println("actionPerformed");
                ftfActionPerformed(e);
            }
        });

When JFormattedTextField is focused it will handle Enter key in actionPerformed method