Question

I tried making a program that flips a coin(shows image of heads first and later shows image of tails) and I encountered problems trying to have the image of the coin viewed when I ran the problem; only a blank screen would show. I don’t know whether this is from an improper saving method of the jpg images or from an error in the code. I also came across an error before again coding the program where I had the heads image show and tails image not show.

CoinTest.java runs coin runner and Coin.java is the class for the program.

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

public class CoinTest extends JPanel
implements ActionListener
{
  private Coin coin;

  public CoinTest ()
{
Image heads = (new ImageIcon("quarter-coin-head.jpg")).getImage();
Image tails = (new ImageIcon("Indiana-quarter.jpg")).getImage();
coin = new Coin(heads, tails);

Timer clock = new Timer(2000, this);
clock.start();
}

public void paintComponent(Graphics g)
{
super.paintComponent(g);

int x = getWidth() / 2;
int y = getHeight() / 2;
coin.draw(g, x, y);
}

 public void actionPerformed(ActionEvent e)
   {
    coin.flip();
    repaint();
   }

public static void main(String[] args)
{
JFrame w = new JFrame("Flipping coin");
w.setSize(300, 300);
w.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    CoinTest panel = new CoinTest();
    panel.setBackground(Color.WHITE);
    Container c = w.getContentPane();
    c.add(panel);

    w.setVisible(true);
  }
}

Now the actual Coin class.

import java.awt.Image;
import java.awt.Graphics;

public class Coin
{
private Image heads;
private Image tails;
private int side = 1;

public Coin(Image h, Image t)
{
    heads = h;
    tails = t;
}

//flips the coin
public void flip()
{
    if (side == 1)
        side = 0;
    else
        side = 1;
}

//draws the appropriate side of the coin - centered  in the JFrame
public void draw(Graphics g, int x, int y)
{
    if (side == 1)
    g.drawImage(heads, heads.getWidth(null)/3, heads.getHeight(null)/3, null);
    else 
    g.drawImage(heads, tails.getWidth(null)/3, tails.getHeight(null)/3, null);
}
}

Answer 1

Firstly, ensure that both images are in the correct location to load.

Secondly, you have a typo here:

if (side == 1)
  g.drawImage(heads, heads.getWidth(null)/3, heads.getHeight(null)/3, null);
else 
  g.drawImage(heads, tails.getWidth(null)/3, tails.getHeight(null)/3, null);
              ^^^^

should be tails…