Alternative solution on randomizing JLabel

Question

So, I have this task where the user guess the correct number just by clicking on the JLabel I have presented for them. What I was trying to is to generate a random number then use if (e.getSource() == random) { } but it seems object and int isn't a compatible operand and I was hoping if someone has any solution to this.

Anyways, here is the source code of what I am doing nothing good since I don't have any solution on my first problem yet.

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.BorderLayout;
import java.awt.Font;
import java.util.Random;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class Test123 {

private JFrame frame;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                Test123 window = new Test123();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the application.
 */
public Test123() {
    initialize();
}

/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    
    Random generator = new Random();
    int num;
    num = generator.nextInt(9) + 1;
    int count = 0;
    
    frame = new JFrame();
    frame.setBounds(100, 100, 405, 195);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(null);
    
    JLabel NO1 = new JLabel("1");
    NO1.setBounds(20, -26, 43, 183);
    NO1.setFont(new Font("Arial", Font.BOLD, 75));
    frame.getContentPane().add(NO1);
    
    JLabel NO2 = new JLabel("2");
    NO2.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO2.setFont(new Font("Arial", Font.BOLD, 75));
    NO2.setBounds(60, -26, 43, 183);
    frame.getContentPane().add(NO2);
    
    JLabel NO3 = new JLabel("3");
    NO3.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO3.setFont(new Font("Arial", Font.BOLD, 75));
    NO3.setBounds(102, -26, 43, 183);
    frame.getContentPane().add(NO3);
    
    JLabel NO4 = new JLabel("4");
    NO4.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO4.setFont(new Font("Arial", Font.BOLD, 75));
    NO4.setBounds(143, -26, 43, 183);
    frame.getContentPane().add(NO4);
    
    JLabel NO5 = new JLabel("5");
    NO5.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO5.setFont(new Font("Arial", Font.BOLD, 75));
    NO5.setBounds(184, -26, 43, 183);
    frame.getContentPane().add(NO5);
    
    JLabel NO6 = new JLabel("6");
    NO6.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO6.setFont(new Font("Arial", Font.BOLD, 75));
    NO6.setBounds(223, -26, 43, 183);
    frame.getContentPane().add(NO6);
    
    JLabel NO7 = new JLabel("7");
    NO7.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO7.setFont(new Font("Arial", Font.BOLD, 75));
    NO7.setBounds(264, -26, 43, 183);
    frame.getContentPane().add(NO7);
    
    JLabel NO8 = new JLabel("8");
    NO8.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO8.setFont(new Font("Arial", Font.BOLD, 75));
    NO8.setBounds(304, -26, 43, 183);
    frame.getContentPane().add(NO8);
    
    JLabel NO9 = new JLabel("9");
    NO9.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
        }
    });
    NO9.setFont(new Font("Arial", Font.BOLD, 75));
    NO9.setBounds(345, -26, 43, 183);
    frame.getContentPane().add(NO9);
    
    JLabel CorrectAns = new JLabel("Correct!");
    CorrectAns.setEnabled(false);
    CorrectAns.setBounds(181, 132, 46, 14);
    frame.getContentPane().add(CorrectAns);
    
    NO1.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
            if (e.getSource() == num) {
                count++;
                CorrectAns.setText("Correct!" + count + " attempts");
            }
        }
    });
}
}

Answer 1

MouseEvent#getSource will return the object which trigged the event, in your case, the JLabel.

A "generally" better solution might be to use JButton instead, then take advantage of the ActionListener. I'd attach a single ActionListener to the "correct" button to handle the correct workflow and a ActionListener to the others to handle the incorrect state

See How to Use Buttons, Check Boxes, and Radio Buttons and How to Write an Action Listener for more details

import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Random;
import java.util.Set;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Twst {
    public static void main(String[] args) {
        new Twst();
    }

    public Twst() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new GridBagLayout());
            randomButtons();
        }

        protected void randomButtons() {
            removeAll();
            List<JButton> buttons = new ArrayList<>(4);
            Random rnd = new Random();
            Set<Integer> numbers = new HashSet<>();
            while (numbers.size() < 4) {
                int number = rnd.nextInt(99) + 1;
                numbers.add(number);
            }

            for (Integer number : numbers) {
                JButton btn = new JButton(Integer.toString(number));
                add(btn);
                buttons.add(btn);
            }

            Collections.shuffle(buttons);
            JButton correct = buttons.remove(0);
            correct.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent evt) {
                    JOptionPane.showMessageDialog(TestPane.this, "Correct");
                    randomButtons();
                }
            });

            ActionListener wrong = new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent evt) {
                    if (evt.getSource() instanceof JButton) {
                        JButton btn = (JButton) evt.getSource();
                        btn.setEnabled(false);
                    }
                    JOptionPane.showMessageDialog(TestPane.this, "Wrong");
                    // You could keep a counter or do what ever else you
                    // want with a wrong guess
                }
            };
            for (JButton btn : buttons) {
                btn.addActionListener(wrong);
            }
            revalidate();
            repaint();
        }

    }
}