Adding textfield validation to multiple textfields

Question

I'm trying to add validation to 4 JTextFields using only numeric characters (0-9). The code I have for one JTextField is:

txtf_xCoord.addKeyListener(new KeyAdapter()
    {
        @Override
        public void keyTyped(KeyEvent keyEvent)
        {
            if (txtf_xCoord.getText().length() < 3 && keyEvent.getKeyChar() >= '0' && keyEvent.getKeyChar() <= '9')
            {
                // Optional
                super.keyTyped(keyEvent);
            }
            else
            {
                // Discard the event
                keyEvent.consume();
            }
        }
    });

Is there a more efficient way of adding this validation to the rest of the JTextFields without copy and pasting the code for each?

make a class that extends from JTextField and in it add your listener. and everywhere of your program create of that class. — mehdi, Mar 07 '12 at 13:19
@medhi - wrong ... you _never_ use a KeyListener in Swing, especially not for validating text input — kleopatra, Mar 07 '12 at 14:45

score 3 · Answer 1 · answered Mar 07 '12 at 13:18

You can use an InputVerifier, take a look at the following code :

public class NumericVerifier extends InputVerifier {
        @Override   
    public boolean verify(JComponent input) {
            //Check type of the control
                String text = "";

if(input instanceof JTextField) {   
                JTextField tf = (JTextField) input; 
                text = tf.getText().trim(); 
            }

        boolean matches = text.matches("^\\d+$");
        input.setBackground( ( matches ) ? Color.WHITE :  Color.RED);
        return matches; 
    }   
}

score 2 · Answer 2 · edited May 23 '17 at 12:21

2

easiest and most safiest way would be to add one instance of DocumentFilter to the JTextFields
never use KeyListener for Swing JComponent, use KeyBindings instead
for listening in the JTextComponents is there DocumentListener

edited May 23 '17 at 12:21

Community

1
1

answered Mar 07 '12 at 13:22

mKorbel

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score 1 · Answer 3 · answered Mar 07 '12 at 13:19

1

Well you can convert your anonymous class to a real class and then instantiate that class everywhere. Now, you could also take a look at JFormattedTextField

answered Mar 07 '12 at 13:19

Guillaume Polet

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Adding textfield validation to multiple textfields

3 Answers3