Question

I am new to Java, and the whole working with arrays + using classes and their methods to populate and display the arrays. I have spent the last 2-3 hours, working on this and checking google for various answers and none have seemed to help, I am still stuck. I don’t really know how to use the methods from the rectangle1 class, when using arrays.

Main class:

public static void main(String[] args) {
    GameBoard frame = new GameBoard();
}

GameBoard Class

public class GameBoard extends JFrame {

    public GameBoard() {

        JFrame frame = new JFrame();
        frame.setBounds(0, 0, 195, 215);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Rectangle1 board[][] = new Rectangle1[3][3];
        for (int row = 0; row < board.length; row++) {
            for (int col = 0; col < board[row].length; col++) {
                board[row][col] = new Rectangle1(0, 0, 195, 215);
                if ((row + col) % 2 == 0) {
                    Graphics g = null;    
                    board[row][col].paint(g);
                    g.setColor(Color.yellow);
                    g.fillRect(0, 0, 195, 215);
                } else {
                    Graphics h = null;
                    board[row][col].paint(h);
                    h.setColor(Color.red);
                    h.fillRect(0, 0, 195, 215);
                }
                frame.add(board[row][col]);
            }    
        }  

    }
}

Rectangle1 class.

public class Rectangle1 extends JComponent  {

    /** post:   getX() == x  and  getY() == y
     *          and  getWidth() == w  and getHeight() == h
     *          and  getBackground() == Color.black
     */
    public Rectangle1(int x, int y, int w, int h)  {
        super();
        setBounds(x, y, w, h);
        setBackground(Color.black);
    }

    /** post:   this method draws a filled Rectangle
     *          and  the upper left corner is (getX(), getY()) 
     *          and  the rectangle's dimensions are getWidth() and getHeight()
     *          and  the rectangle's color is getBackground()
     */
    public void paint(Graphics g)  {
        g.setColor( getBackground() );
        g.fillRect(0, 0, getWidth()-1, getHeight()-1);
        paintChildren(g);
   }

}

Answer 1

Firstly, you are fighting the layout manager, calling something like setBounds(x, y, w, h) in you Rectangle class is going to overridden by the layout manager of the parent container (the frame in this case)

Secondly, you are not responsible for painting, do this;

board[row][col].paint(g);
g.setColor(Color.yellow);
g.fillRect(0, 0, 195, 215);

…is wrong. If it doesn’t end up with you programming crashing, then your lucky.

While I try and figure out a solution, you might like to take some time and read through

• Creating a GUI With JFC/Swing, and Laying Out Components Within a Container
• 2D Graphics
• Performing Custom Painting
• Painting in AWT and Swing

While on my rant…

This;
public void paint(Graphics g) {
g.setColor( getBackground() );
g.fillRect(0, 0, getWidth()-1, getHeight()-1);
paintChildren(g);
}

is inappropriate. You MUST call super.paint(), there’s to much going on in the background for you to override this method without calling it’s super.

In fact, you should avoid overriding paint where ever possible and user paintComponent instead.

Also, coordinates in Swing are relative to the component. That is, the top/left corner of any component (within the context of the component) is always 0x0

Here’s a working example

public class TestBoard {

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

    public TestBoard() {

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {

                new GameBoard();

            }
        });

    }

    public class GameBoard extends JFrame {

        public GameBoard() {

            JFrame frame = new JFrame();
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridx = 0;
            gbc.gridy = 0;

            Rectangle1 board[][] = new Rectangle1[3][3];
            for (int row = 0; row < board.length; row++) {

                gbc.gridx = 0;

                for (int col = 0; col < board[row].length; col++) {
                    board[row][col] = new Rectangle1(195, 215);
                    if ((row + col) % 2 == 0) {
                        board[row][col].setBackground(Color.YELLOW);
                    } else {
                        board[row][col].setBackground(Color.RED);
                    }
                    frame.add(board[row][col], gbc);
                    gbc.gridx++;
                }

                gbc.gridy++;

            }

            frame.pack();
            frame.setVisible(true);

        }
    }

    public class Rectangle1 extends JPanel {

        public Rectangle1(int w, int h) {
            setPreferredSize(new Dimension(w, h));
        }

    }
}

Because of the nature of your requirements, I’ve been forced to use GridBagLayout which is not the simplest of layout managers to use.

JComponents are transparent by nature and you are required to fill them, better to use JPanel