Auto filling a JTextField in GUI

Question

I am currently creating GUI using Netbeans in Java. How to make a JTextField auto fill to contain the current system date when I load the JFrame that contains that text field using a JButton from another frame?

Answer 1

1. Given the JTextField can be constructed (instantiated) when the button is pressed, fill it with the current date / time when constructed.
2. See any number of components that are better suited to displaying (and allowing the user to choose) a date. E.G. new JSpinner(new SpinnerDateModel()); - incidentally new SpinnerDateModel() defaults to the current date!

Here is an example of using the spinner / spinner date model.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;

public class DateSpinner {

    private JComponent ui = null;

    DateSpinner() {
        initUI();
    }

    public void initUI() {
        if (ui!=null) return;

        ui = new JPanel(new BorderLayout(4,4));
        ui.setBorder(new EmptyBorder(100,100,100,100));

        JButton dateSelector = new JButton("Select a date (after now)");
        ActionListener dateSelectorListener = new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                SpinnerDateModel spinnerDateModel = new SpinnerDateModel();
                JSpinner spinner = new JSpinner(spinnerDateModel);
                JOptionPane.showMessageDialog(
                        ui, spinner, "Choose Date", JOptionPane.QUESTION_MESSAGE);
                System.out.println("Date Chosen: " + spinnerDateModel.getDate());
            }
        };
        dateSelector.addActionListener(dateSelectorListener);
        ui.add(dateSelector);
    }

    public JComponent getUI() {
        return ui;
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception useDefault) {
                }
                DateSpinner o = new DateSpinner();

                JFrame f = new JFrame(o.getClass().getSimpleName());
                f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
                f.setLocationByPlatform(true);

                f.setContentPane(o.getUI());
                f.pack();
                f.setMinimumSize(f.getSize());

                f.setVisible(true);
            }
        };
        SwingUtilities.invokeLater(r);
    }
}