CODEWITHSUNDEEP
javaswinglistenerjtextfield
Laura
Laura

Reputation: 131

Add FocusListener on a JTextField

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?

Upvotes: 0

Views: 2011

Answers (3)

Sergiy Medvynskyy
Sergiy Medvynskyy

Reputation: 11327

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

Upvotes: 3

alex2410
alex2410

Reputation: 10994

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

Upvotes: 0

KernelPanic
KernelPanic

Reputation: 2432

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;
}

Upvotes: 0

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