Add FocusListener on a JTextField

Question

I have a textfield in which i have to validate an Email.My problem is that i want to move the focus from the textfield only when the email is valid.I am using now a FocusAdapter. Can someone please give me some other idea?

I'd hate to have to work with a program that behaves that way. E.G. I'm sitting in front of a screen with 30 fields, and know the values of 29 of them, but the 30th is the email address that I need to get from my co-worker who has popped outside for a smoke. Why limit me from entering the details of the 29 fields I know? *"..give me some other idea?"* Validate all the fields when the operator ***attempts to save the information.*** If there are fields that need fixing, pop a modal dialog explaining the data needed & drop them back into the form, with field focused. — Andrew Thompson, Nov 14 '13 at 11:16

score 3 · Answer 1 · edited May 23 '17 at 12:05

3

See javax.swing.InputVerifier and JComponent.setInputVerifier() But don't forget the suggestion from Andrew. Your workflow isn't user friendly.

It was already described here: Java - making a textbox not lose focus

edited May 23 '17 at 12:05

Community

1
1

answered Nov 14 '13 at 11:48

Sergiy Medvynskyy

11,160
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score 0 · Answer 2 · answered Nov 14 '13 at 11:16

0

Try this:

public static boolean isValidEmailAddress(String email)
{
   boolean result=true;
   try
   {
      InternetAddress emailAddr=new InternetAddress(email);
      emailAddr.validate();
   } catch(AddressException ex)
   {
      result=false;
   }
   return result;
}

answered Nov 14 '13 at 11:16

KernelPanic

2,328
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I have validated the Email.My problem is: when i type in some not valid email in the TextField and i move the mouse on another Component ,I need the mouse not to be able to do that,but to stay on the same Textfield until the email is valid. – Laura Nov 14 '13 at 11:22

score 0 · Answer 3 · answered Nov 14 '13 at 11:23

In next example you cant move to another field if validation failed, done with help of requestFocusInWindow() method. Try it, I think it helps you:

public class Frame extends JFrame {

    private JTextField f;
    private JTextField f2;
    private JTextField f3;

    public Frame() {
        f = new JTextField(5);
        f2 = new JTextField(5);
        f3 = new JTextField(5);
        f.addFocusListener(getFocusListener());
        getContentPane().setLayout(new GridLayout(3,1,5,5));
        getContentPane().add(f);
        getContentPane().add(f2);
        getContentPane().add(f3);
        pack();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }

    private FocusListener getFocusListener() {
        return new FocusAdapter() {
            @Override
            public void focusLost(FocusEvent arg0) {
                super.focusLost(arg0);
                if(!validateEmail()){
                    f.requestFocusInWindow();
                }
            }
        };
    }

    private boolean validateEmail() {
        return f.getText().length()<3;
    }

    public static void main(String args[]) {
        new Frame();

    }

}

Read more about requestFocusInWindow() and How to Use the Focus Subsystem

Add FocusListener on a JTextField

3 Answers3