Minesweeper Object GUI

Question

I am trying to do a simple Minesweeper game using JFrame, however I am having troubles with the creation of objects. I am creating 96 buttons, some of which get the property of being wrong ("F") and right ("R"):

public class GUIBase extends JFrame {

private JButton button;
private JButton fButton;


public GUIBase() {
    super("Minesweeper");
    setLayout(new FlowLayout());

    //Fields
    int position;
    for (int i = 0; i < 96; i++) {
        position = (int) (Math.random() * 100);
        if (position < 80) {
            button = new JButton("R");
            button.setToolTipText("Is this the correct one?");
            add(button);
        } else {
            fButton = new JButton("F");
            fButton.setToolTipText("Is this the correct one?");
            add(fButton);
        }           
    }

I then use ActionListener in order to check whether or not the button is correct. If the button is correct, it will get .setEnabled(false), otherwise the game ends:

    //Action
    Action action = new Action();
    button.addActionListener(action);
    fButton.addActionListener(action);

}

private class Action implements ActionListener {

    public void actionPerformed(ActionEvent event) {
        System.out.println("Somethin");

        if (event.getSource() == button) {
            button.setEnabled(false);
        } else if (event.getSource() == fButton) {
            JOptionPane.showMessageDialog(null, "You lost!");
            System.exit(0);
        } else {
            JOptionPane.showMessageDialog(null, "An error ocurred");
            System.exit(0);
        }           
    }
} 

Everything in the game turns out as planned, however only the last correct button ("R") and last wrong one ("F") are connected to the ActionListener. The rest of the buttons do not do anything when pressed.

How can I fix this?

Answer 1

The problem is that you only have two variables (attributes of the class GUIBase, specifically), and your are assigning to it each time you create a new button. Hence, you only have a reference to the last buttons.

You need an array of buttons. Let's see:

public class GUIBase extends JFrame {
    public final int MAX_BUTTONS = 96;
    private JButton[] buttons;
// ...
}

The next step is to create the array itself at the beginning:

public GUIBase() {
    super("Minesweeper");
    setLayout(new FlowLayout());

    this.buttons = new JButton[MAX_BUTTONS];


    //Fields
    int position;
    for (int i = 0; i < buttons.length; i++) {
        position = (int) (Math.random() * 100);

        this.buttons[ i ] = new JButton("R");
        this.buttons[ i ].setToolTipText("Is this the correct one?");
        this.add(this.buttons[ i ]);

        Action action = new Action();
        this.buttons[ i ].addActionListener(action);
    }
}

You'll probably need more depth in arrays in order to completely understand the code. Basically, an array is a continuous collection of variables, which you can index by its position, from 0 to n-1, being n the number of positions.

Then you'll probably be able to fill the gaps yourself.

Hope this helps.