Java Dice Roller with GUI

Question

Three days ago I wrote about a Java Dice Roller I wrote. I've now added a GUI to that program. Here it is:

DiceRollerGUI.java:

package com.egroegnosbig.dicerollergui;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class DiceRollerGUI {
 static JFrame frameOne = new JFrame("Dice Roller");
 public static void main(String[] args) {
 frameOne.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 DiceGUI GUI = new DiceGUI();
 frameOne.add(GUI);
 Button b = new Button("Roll");
 b.addActionListener(new ButtonAction());
 frameOne.add(b);
 frameOne.setLayout(new GridLayout(1, 2));
 frameOne.setSize(400, 250);
 frameOne.setResizable(false);
 frameOne.setVisible(true);
 }
}
class ButtonAction implements ActionListener {
 @Override
 public void actionPerformed(ActionEvent e) {
 DiceRollerGUI.frameOne.setVisible(false);
 JFrame frameTwo = new JFrame("Dice Roller");
 frameTwo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 frameTwo.setSize(400, 250);
 frameTwo.setResizable(false);
 ResultGUI resultGUI = new ResultGUI();
 frameTwo.add(resultGUI);
 frameTwo.setVisible(true);
 }
}

DiceGUI.java:

package com.egroegnosbig.dicerollergui;
import java.awt.*;
import javax.swing.*;
public class DiceGUI extends JPanel {
 @Override
 public void paintComponent(Graphics g) {
 super.paintComponent(g);
 this.setBackground(Color.WHITE);
 g.drawString("Dice Roller", 70, 20);
 }
}

ResultGUI.java:

package com.egroegnosbig.dicerollergui;
import java.awt.*;
import javax.swing.*;
public class ResultGUI extends JPanel {
 @Override
 public void paintComponent(Graphics g) {
 super.paintComponent(g);
 this.setBackground(Color.WHITE);
 Dice dice = new Dice(6);
 int resultInt = dice.roll();
 StringBuilder sb = new StringBuilder();
 sb.append("");
 sb.append(resultInt);
 String result = sb.toString();
 g.drawString("The dice rolled a", 150, 125);
 g.drawString(result, 243, 125);
 }
}

Dice.java:

package com.egroegnosbig.dicerollergui;
import java.util.Random;
public class Dice {
 private final Random rand;
 private final int faces;
 public Dice(int faces) {
 this.rand = new Random();
 this.faces = faces;
 }
 public int roll() {
 return rand.nextInt(faces) + 1;
 }
}

Working on better class names...

Answer 1

• Rather than swapping out the entire JFrame for another on the button click, you should simply be updating the contents. This is all very overwrought. I think all you really need is a panel with a button and a label. Click the button, and display the results in the label.
• Related to the above, rather than overriding paint, you should be using a layout and adding subcomponents.

To get you started:

public class DicePanel extends JPanel {
 private final Dice dice;
 private JButton rollButton;
 private JLabel displayLabel;
 public DicePanel(Dice dice) {
 this.dice = dice;
 rollButton = new JButton("Roll");
 displayLabel = new JLabel();
 rollButton.addActionListener(e ->
 displayLabel.setText("You rolled a: " + dice.roll())
 );
 // or if you're not using Java 8, you can do the more verbose thing.
 // not specifying a layout defaults to a flow layout. Set a layout via:
 // setLayout(new BorderLayout()); // or whatever
 add(rollButton);
 add(displayLabel);
 }
}

Your program should just create a Dice, create a DicePanel with that, and stick it in a JFrame and show it. Then play around with layouts to get something you like.

• user69731: Nice, fixes my horrible button layout as well!
• user69731: Find the latest version on GitHub.