(Java GUI)Changing the Text of a JButton once its pressed.

[S.Parker]

Homework Statement

Im a big rookie in Java ( and pretty much every language). I am trying to make a Minesweeper game for an assignment and I am still in the beta stages. I am stuck however on how to display the mines as a "0" once the button is pressed. I created the Jbuttons using a 2d array, but I can't seem to put the "0" on the specific button I want.

Here is my code ( please excuse the ugliness/ probable inefficiency) I really am clueless when it comes to GUI's.

Homework Equations

import java.awt.*;
import javax.swing.*;
import java.awt.GridLayout;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.event.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JFrame;

public class Grid extends JPanel {
    // Initializes rows,columns and mines
    int rows = 10;
    int cols = 10;
    int i, j = 0;
    int mines = 10;
    boolean[][] setmine = new boolean[rows][cols];
    boolean[][] clickable = new boolean[rows][cols];
    private JToggleButton squares[][], squares2[][];

    // Contructor for creating a grid(with default size 400x400
    public Grid() {
        this.setSize(600, 600);
        this.setLayout(new GridLayout(rows, cols));
        squares = new JToggleButton[rows][cols];
        buildButtons();
    }

    private void buildButtons() {
        // loops are used for creating the "buttons" on the grid.
        int MinesNeeded = 10;
        // builds buttons
        // ----------------------------------------
        for (i = 0; i < rows; i++) {
            for (j = 0; j < cols; j++) {
                squares[i][j] = new JToggleButton();
                // squares[i][j].setEnabled(false);
                squares[i][j].setSize(600, 600);

                // --------------------------------------------------
                // This part randomises the mines
                // -----------------------------------------------------
                while (MinesNeeded > 0) {

                    int x = (int) Math.floor(Math.random() * rows);
                    int y = (int) Math.floor(Math.random() * cols);
                    if (!setmine[x][y]) {
                        setmine[x][y] = true;

                        MinesNeeded--;
                    }
                }
                // ----------------------------------------------------------------------------

                this.add(squares[i][j]);

                if (setmine[i][j] == true) {

                    squares[i][j].addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent ae) {
                            // this is the problem
                            squares[i][j].setText("0");
                        }
                    });
                }
            }
        }
    }

    public static void main(String[] args) {
        Grid g = new Grid();
        JFrame frame = new JFrame("Minesweeper");

        frame.add(g);
        frame.setSize(600, 600);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

The Attempt at a Solution

 

[gabbagabbahey]

I think the problem is that when actionPerformed is called, you have already completely gone through your loops, and so i=j=10, and of course, squares[10][10] will throw an index out of range exception. Instead of using squares[j] in that method, try utilizing the method parameter ae in order to set the text on the correct button.

 

[S.Parker]

I think the problem is that when actionPerformed is called, you have already completely gone through your loops, and so i=j=10, and of course, squares[10][10] will throw an index out of range exception. Instead of using squares[j] in that method, try utilizing the method parameter ae in order to set the text on the correct button.

Thank you for the swift reply. I am almost 100% sure that is the problem. Could you guide me on how to use the method parameter to set the text? (I don't understand what the method parameter does in Action Listener ( I used ActionListener for the first time yersterday))

 

[S.Parker]

Nevermind, I got it to work. Thanks a lot

 

[rezeew]

I would approach this problem by first understanding the basic concepts of Java GUI and how to manipulate components such as JButtons. From the provided code, it seems that the programmer has successfully created a grid of JButtons and randomized the placement of mines. However, the issue lies in changing the text of a specific JButton once it is clicked.

To solve this problem, I would suggest using an ActionListener for each JButton that will be responsible for changing its text. In the provided code, the ActionListener is only added for JButtons that contain a mine, but it should be added for all JButtons. This way, when a JButton is clicked, its ActionListener will be triggered and the text can be changed accordingly.

Additionally, instead of using a 2D array to store the JButtons, I would recommend using a 2D array of JButton objects. This way, each JButton can be accessed and manipulated easily using its coordinates in the grid.

Furthermore, I would also suggest using a separate method to check for the presence of mines and display the appropriate number on the JButton. This method can be called from within the ActionListener and can take in the coordinates of the JButton as parameters.

Overall, my approach would be to break down the problem into smaller, manageable tasks and use proper programming techniques to solve them. With a thorough understanding of Java GUI and proper implementation, I am confident that the programmer can successfully display the mines as "0" on the specific JButton they want.