Trying to use actionListener to turn a String upside down

Question

From my textbook: "Write an application that extends JFrame and that displays a phrase upside down when the user click a button. The phrase is displayed normally when the user clicks the button again."

Currently I have a String that is drawn using the paint() method and a Graphic object. The String is visible in the JUpsideDown frame and it's upside down and positioned in about the middle of the panel. I've added my button and a actionListener but I think the code in my actionPerformed method is wrong because I'm trying to make the negative font size a positive by multiplying by -1 but it doesn't seem to take effect when I repaint. The String positioned is moved to x = 100 ad y = 100 but the String is still upside down.

Any kind of guidance is appreciated.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
@SuppressWarnings("serial")
public class JUpsideDown extends JFrame implements ActionListener
{
    int x = 350;
    int y = 100;
    int fontSize = -26;
    Font font = new Font("Serif", Font.PLAIN, fontSize);
    JButton press = new JButton("Flip Text");
    String label = "Look at this text, it will flip!";

    public JUpsideDown()
    {
        setTitle("JUpsideDown");
        setLayout(new FlowLayout());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        add(press);
        press.addActionListener(this);
    }

    public void paint(Graphics g)
    {
        super.paint(g);
        g.setFont(font);
        g.drawString(label, x, y);
    }

    public void actionPerformed(ActionEvent e)
    {
        fontSize = fontSize * -1;
        x = 100;
        y = 100;
        repaint();
    }

    public static void main(String[] args) 
    {
        JUpsideDown frame = new JUpsideDown();
        frame.setSize(450, 200);
        frame.setVisible(true);

    }

}

Answer 1

Your logic is right, although you need to instantiate again a new Font object which will encapsulate the new fontsize. This should be performed after the button is clicked inside actionPerformed() method. In this way the behavior of the application will be the expected.

Below you may find a possible solution:

public void actionPerformed(ActionEvent e)
    {
        fontSize = fontSize * -1;
        x = 100;
        y = 100;
        font = new Font("Serif", Font.PLAIN, fontSize); //added line
        repaint();
    }