How to Display Message When i left JTextField in java

Question

Actually i'm writing code. I want to display message dialogue (without pressing any button) when I left my JTextField but don't know how to do this. Please Help. Im using NetBeans.

Answer 1

You can use Focus Listener API to achieve that.

On focusLost event, you can show your dialog box.

Example from the documentation:

public void focusLost( FocusEvent e )
{
    displayMessage( "Focus lost", e );
}

Answer 2

You can use FocusListener class focusLost() method.

Simple Example:

import java.awt.FlowLayout;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class ExampleClass {
    JFrame MainFrame;
    JTextField textField1;
    JTextField textField2;

    public ExampleClass(){
        MainFrame = new JFrame("Example");
        MainFrame.setLayout(new FlowLayout());

        textField1 = new JTextField(10);
        textFieldFocus();

        textField2 = new JTextField("Dummy text");

        MainFrame.add(textField1);
        MainFrame.add(textField2);
        MainFrame.pack();
        MainFrame.setVisible(true);
    }
    private void textFieldFocus() {                                     
        textField1.addFocusListener(new FocusListener() {

            @Override
            public void focusLost(FocusEvent e) {
                JOptionPane.showMessageDialog(null, "Done!");

            }

            @Override
            public void focusGained(FocusEvent e) {}
        });
    }
    public static void main(String[] args) {
        new ExampleClass();
    }
}