We have built a Point of Sale system and now we require to implement it to Touch screens? Do we need to change any code in turn to allow this to work.

And we are using the Keyboard to enter values - let's say quantity - Is there a java way of popping up a key board (like android) when I focus on a JTextField?

Here is a simple example on how to implement a pop-up keyboard:

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

@SuppressWarnings("serial")
public class MainFrame extends JFrame
{
    private JTextField txt;
    private PopUpKeyboard keyboard;

    public MainFrame()
    {
        super("pop-up keyboard");
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        txt = new JTextField(20);
        keyboard = new PopUpKeyboard(txt);

        txt.addMouseListener(new MouseAdapter()
        {
            @Override
            public void mouseClicked(MouseEvent e)
            {
                Point p = txt.getLocationOnScreen();
                p.y += 30;
                keyboard.setLocation(p);
                keyboard.setVisible(true);
            }
        });
        setLayout(new FlowLayout());
        add(txt);

        pack();
        setLocationByPlatform(true);
    }

    public static void main(String[] args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                new MainFrame().setVisible(true);
            }
        });
    }

    private class PopUpKeyboard extends JDialog implements ActionListener
    {
        private JTextField txt;

        public PopUpKeyboard(JTextField txt)
        {
            this.txt = txt;
            setLayout(new GridLayout(3, 3));
            for(int i = 1; i <= 9; i++) createButton(Integer.toString(i));
            pack();
        }

        private void createButton(String label)
        {
            JButton btn = new JButton(label);
            btn.addActionListener(this);
            btn.setFocusPainted(false);
            btn.setPreferredSize(new Dimension(100, 100));
            Font font = btn.getFont();
            float size = font.getSize() + 15.0f;
            btn.setFont(font.deriveFont(size));
            add(btn);
        }

        @Override
        public void actionPerformed(ActionEvent e)
        {
            String actionCommand = e.getActionCommand();
            txt.setText(txt.getText() + actionCommand);
        }
    }
}

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