Allowing the Enter key to press the submit button as opposed to only using MouseClick

Question

I m learning Swing class now and everything about it  I ve got this toy program I ve been putting together that prompts for a name and then presents a JOptionPane with the message  You ve entered  Your Name    The submit button I use can only be clicked on  but I d like to get it to work with the Enter button too  I ve tried adding a KeyListener  as is recommended in the Java book I m using  Eventful Java  Bruce Danyluk and Murtagh       This is my code   import java awt BorderLayout  import java awt event ActionEvent  import java awt event ActionListener   import javax swing JButton  import javax swing JFrame  import javax swing JLabel  import javax swing JPanel  import javax swing JTextField    public class NamePrompt extends JFrame        private static final long serialVersionUID   1L       String name       public NamePrompt             setLayout new BorderLayout              JLabel enterYourName   new JLabel  Enter Your Name Here             JTextField textBoxToEnterName   new JTextField 21           JPanel panelTop   new JPanel            panelTop add enterYourName           panelTop add textBoxToEnterName            JButton submit   new JButton  Submit            submit addActionListener new SubmitButton textBoxToEnterName            submit addKeyListener new SubmitButton textBoxToEnterName            JPanel panelBottom   new JPanel            panelBottom add submit              Add panelTop to JFrame         add panelTop  BorderLayout NORTH           add panelBottom  BorderLayout SOUTH              JFrame set-up         setTitle  Name Prompt Program            setDefaultCloseOperation EXIT ON CLOSE           pack            setLocationRelativeTo null                  public static void main String   args            NamePrompt promptForName   new NamePrompt            promptForName setVisible true                And this is the actionListener  keyListener class   import java awt Component  import java awt event ActionEvent  import java awt event ActionListener  import java awt event KeyEvent  import java awt event KeyListener   import javax swing JFrame  import javax swing JOptionPane  import javax swing JTextField    public class SubmitButton implements ActionListener  KeyListener        JTextField nameInput        public SubmitButton JTextField textfield           nameInput   textfield              Override     public void actionPerformed ActionEvent submitClicked             Component frame   new JFrame            JOptionPane showMessageDialog frame    You ve Submitted the name     nameInput getText                 Override     public void keyPressed KeyEvent e            if  e getKeyCode    KeyEvent VK ENTER               System out println  Hello                      Component frame   new JFrame            JOptionPane showMessageDialog frame    You ve Submitted the name     nameInput getText                  Override     public void keyReleased KeyEvent arg0               TODO Auto-generated method stub              Override     public void keyTyped KeyEvent arg0

User · Answer

textField in   new JTextField    textField in addKeyListener new KeyAdapter           Override     public void keyPressed KeyEvent arg0            System out println arg0 getExtendedKeyCode             if  arg0 getKeyCode    10                String name   textField in getText                textField out setText name                         textField in setBounds 173  40  86  20   frame getContentPane   add textField in   textField in setColumns 10

User · Answer

I know this isn t the best way to do it  but right click the button in question  events  key  key typed  This is a simple way to do it  but reacts to any key

User · Answer

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     And the problem with your code as far as I see is that your dialog pops up every time you hit a key  because you didn t put it in the if-body  Try changing it to this    Override public void keyPressed KeyEvent e        if  e getKeyCode    KeyEvent VK ENTER           System out println  Hello             JOptionPane showMessageDialog null    You ve Submitted the name     nameInput getText                  UPDATE  I found what is wrong with your code  You are adding the key listener to the Submit button instead of to the TextField  Change your code to this   SubmitButton listener   new SubmitButton textBoxToEnterName   textBoxToEnterName addActionListener listener   submit addKeyListener listener

User · Answer

You can use the top level containers root pane to set a default button  which will allow it to respond to the enter   SwingUtilities getRootPane submitButton  setDefaultButton submitButton     This  of course  assumes you ve added the button to a valid container     UPDATED  This is a basic example using the JRootPane setDefaultButton and key bindings API  public class DefaultButton        public static void main String   args            new DefaultButton               public DefaultButton             EventQueue invokeLater new Runnable                  Override             public void run                     try                       UIManager setLookAndFeel UIManager getSystemLookAndFeelClassName                       catch  ClassNotFoundException   InstantiationException   IllegalAccessException   UnsupportedLookAndFeelException ex                                       JFrame frame   new JFrame  Test                    frame setDefaultCloseOperation JFrame EXIT ON CLOSE                   frame setLayout new BorderLayout                     frame add new TestPane                     frame pack                    frame setLocationRelativeTo null                   frame setVisible true                                         public class TestPane extends JPanel            private JButton button          private JLabel label          private int count           public TestPane                  label   new JLabel  Press the button                button   new JButton  Press me                 setLayout new GridBagLayout                 GridBagConstraints gbc   new GridBagConstraints                gbc gridy   0              add label  gbc               gbc gridy                add button  gbc               gbc gridy                add new JButton  No Action Here    gbc                button addActionListener new ActionListener                      Override                 public void actionPerformed ActionEvent e                        doButtonPressed e                                                   InputMap im   button getInputMap WHEN ANCESTOR OF FOCUSED COMPONENT               ActionMap am   button getActionMap                 im put KeyStroke getKeyStroke KeyEvent VK SPACE  0    spaced                am put  spaced   new AbstractAction                      Override                 public void actionPerformed ActionEvent e                        doButtonPressed e                                                           Override         public void addNotify                 super addNotify                SwingUtilities getRootPane button  setDefaultButton button                      protected void doButtonPressed ActionEvent evt                count                label setText  Pressed     count     times                          This of course  assumes that the component with focus does not consume the key event in question  like the second button consuming the space or enter keys

User · Answer

In the ActionListener Class you can simply add  public void actionPerformed ActionEvent event        if  event getSource    textField           textButton doClick              else if  event getSource    textButton              do something

User · Answer

Without a frame this works for me   JTextField tf   new JTextField 20   tf addKeyListener new KeyAdapter        public void keyPressed KeyEvent e        if  e getKeyCode    KeyEvent VK ENTER          SwingUtilities getWindowAncestor e getComponent    dispose                  String   options     Ok    Cancel    int result   JOptionPane showOptionDialog      null  tf   Enter your message        JOptionPane OK CANCEL OPTION      JOptionPane QUESTION MESSAGE      null      options 0    message   tf getText

User · Answer

switch KEYEVENT getKeyCode           case KeyEvent VK ENTER                I was trying to use case 13 from the ascii table               Krewn Generated method stub                break

[java] Allowing the "Enter" key to press the submit button, as opposed to only using MouseClick

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