按下 Enter 键时调用一系列操作

Question

I have one Swing project and I have an action listener on JTextField for Tab key as follows.

There is a JOptionPane.showMessageDialog() inside the action listener. And when Tab is pressed option pane will show an Information message.

My problem is that, when I press Enter on OK button of Information Message dialog, a serie of action is invoked viz Tab action of JTextField and Enter action of btnNewButton .

If I use mouse click on OK button of Error Message dialog, every thing is fine and no problem.

Can I solve this using key bindings instead of key listener?

Please suggest a solution

import java.awt.EventQueue;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Collections;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class Test extends JFrame {
    private JPanel contentPane;
    private JTextField textField;
    private JButton btnNewButton;
    private JDialog dialog;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Test frame = new Test();
                    frame.setVisible(true);
                }
                catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public Test() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        setLocationRelativeTo(null);
        contentPane.setLayout(null);

        textField = new JTextField();
        textField.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
                Collections.emptySet());
        textField.addKeyListener(new java.awt.event.KeyAdapter() {
            public void keyPressed(java.awt.event.KeyEvent evt) {
                if (evt.getKeyCode() == KeyEvent.VK_TAB) {
                    JOptionPane.showMessageDialog(dialog, " Please Press ENTER Key", "information",
                            JOptionPane.INFORMATION_MESSAGE);

                    btnNewButton.grabFocus();
                }
            }
        });
        textField.setBounds(73, 28, 178, 28);
        contentPane.add(textField);
        textField.setColumns(10);

        btnNewButton = new JButton("New button");
        btnNewButton.addKeyListener(new KeyAdapter() {
            @Override
            public void keyReleased(KeyEvent e) {
                if (e.getKeyCode() == KeyEvent.VK_ENTER) {
                    JOptionPane.showMessageDialog(dialog, " That Invoked New Button Also", "Error",
                            JOptionPane.ERROR_MESSAGE);
                }
            }
        });
        btnNewButton.setBounds(223, 137, 117, 25);
        contentPane.add(btnNewButton);

        JLabel lblNewLabel = new JLabel("Please Press TAB Key");
        lblNewLabel.setBounds(83, 55, 183, 15);
        contentPane.add(lblNewLabel);

        dialog = new JDialog();
        dialog.setAlwaysOnTop(true);
    }
}

Answer 1

The problem is that you are overriding method keyReleased() . The JOptionPane is closing before the keyReleased() method is called and since you make btnNewButton the focused component after the JOptionPane is closed, the keyReleased() method is invoked – which displays the other JOptionPane .

Simply rename the method to keyPressed() .

Also, you don't need the dialog member. The first parameter to JOptionPane#showMessageDialog should be the JFrame .

Here is your code with my corrections.

import java.awt.EventQueue;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Collections;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class Test extends JFrame {
    private JPanel contentPane;
    private JTextField textField;
    private JButton btnNewButton;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Test frame = new Test();
                    frame.setVisible(true);
                }
                catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public Test() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        setLocationRelativeTo(null);
        contentPane.setLayout(null);

        textField = new JTextField();
        textField.setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
                Collections.emptySet());
        textField.addKeyListener(new java.awt.event.KeyAdapter() {
            public void keyPressed(java.awt.event.KeyEvent evt) {
                if (evt.getKeyCode() == KeyEvent.VK_TAB) {
                    JOptionPane.showMessageDialog(Test.this, " Please Press ENTER Key", "information",
                            JOptionPane.INFORMATION_MESSAGE);
                    btnNewButton.grabFocus();
                }
            }
        });
        textField.setBounds(73, 28, 178, 28);
        contentPane.add(textField);
        textField.setColumns(10);

        btnNewButton = new JButton("New button");
        btnNewButton.addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent e) {
                if (e.getKeyCode() == KeyEvent.VK_ENTER) {
                    JOptionPane.showMessageDialog(Test.this, " That Invoked New Button Also", "Error",
                            JOptionPane.ERROR_MESSAGE);
                }
            }
        });
        btnNewButton.setBounds(223, 137, 117, 25);
        contentPane.add(btnNewButton);

        JLabel lblNewLabel = new JLabel("Please Press TAB Key");
        lblNewLabel.setBounds(83, 55, 183, 15);
        contentPane.add(lblNewLabel);
    }
}

Note that (at least in JDK 15) there is no need to explicitly set the default close operation for JFrame since the default is EXIT_ON_CLOSE