Extended JPanel ruins GridLayout

Question

I am wanting to modify my JPanel like this:

public class Square extends JPanel {
    private Checker fromChecker;
    private int x;
    private int y;

    Square(int x, int y){
        this.x = x;
        this.y = y;
    }

    public int getX(){ return this.x; }
    public int getY(){ return this.y; }

    void setPossibleMoveChecker(Checker fromChecker){ this.fromChecker = fromChecker; }
    Checker getPossibleMoveChecker(){ return this.fromChecker; }
}

and I call Square here:

JPanel panel = new JPanel();
panel.setLayout(new GridLayout(Game.grid_size, Game.grid_size));

for(int x=1; x <= Game.grid_size; x ++){
    for(int y=1; y <= Game.grid_size; y ++) {
        Square square = new Square(x, y);

        // grid colour
        Color square_color = Game.grid1_colour;
        if((x + y) % 2 == 0){
            square_color = Game.grid2_colour;
        }
        square.setBackground(square_color);
        square.addMouseListener(new Mouse());
        panel.add(square);
    }
}

Unfortunately this comes out like:

Where as if I change the line:

Square square = new Square(x, y);

to

JPanel square = new JPanel();

it comes out perfectly like:

Answer 1

You're overriding two key JComponent methods, getX() and getY() , and this is messing with the placement of components since this is one of the key behaviors the layout managers use for component placement.

Solution: Re-name those methods!

public class Square extends JPanel {
    private Checker fromChecker;
    private int column;
    private int row;

    Square(int column, int row){
        this.column = column;
        this.row = row;
    }

    public int getColumn(){ 
        return this.column; 
    }

    public int getRow(){ 
        return this.row; 
    }

    // ....

Yet another reason to favor composition over inheritance, especially when dealing with complex classes that have many potentially overrideable methods.