Java layout problem

Question

I've got 3 classes in my program.

public class Field extends JLabel{

    private int x, y;

    public Field(int x, int y){
        this.x = x;
        this.y = y;
        setOpaque(true);
        setMinimumSize(new Dimension(50,50));
        setPreferredSize(new Dimension(75,75));
        if((x + y) % 2 == 0)
            setBackground(Color.GREEN);
        else
            setBackground(Color.YELLOW);
    }


public class Board extends JPanel{

    public Field[][] fields = new Field[8][8];

    public Board(){
        setLayout(new GridLayout(8,8));
        setMinimumSize(new Dimension(500,500));
        setPreferredSize(new Dimension(550,550));
        setBackground(Color.RED);
        fillBoard();
    }

    private void fillBoard(){
        for(int i = 0; i < 8; ++i){
            for(int j = 0; j < 8; ++j){
                fields[i][j] = new Field(i, j);
                add(fields[i][j]);
            }
        }
    }

public class GUI extends JFrame{

    public Board board;

    private GUI(){
        board = new Board();
        setLayout(new FlowLayout());
        add(board);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        pack();
    }

    public static void main(String[] args){
        SwingUtilities.invokeLater(new Runnable(){
            public void run() {
                new GUI();
            }
        });
    }

}

Whenever I run the program, this appears instead of a yellow-green board. Can anyone help please?

Can you describe in more detail what you expect it to look like? — mgiuca
– mgiuca, Commented Jun 28, 2011 at 0:28
When I run your code, I get a green/yellow checkerboard with a slight red border on the right side and on the bottom. — Hovercraft Full Of Eels
– Hovercraft Full Of Eels, Commented Jun 28, 2011 at 0:37
Presumably just a typo in the question but the class Field doesn't get closed — barrowc
– barrowc, Commented Jun 28, 2011 at 0:43
Note that you should generally call pack() before setVisible(true). — jfpoilpret
– jfpoilpret, Commented Jun 28, 2011 at 7:16

trashgod · Accepted Answer · 2011-06-28 00:46:57Z

3

Your posted code does not compile. Re-factoring into nested classes made it work ~~correctly~~ as shown, so I'm guessing you have a project level problem.

enter image description here

import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class GUI extends JFrame {

    private Board board;

    private GUI() {
        board = new Board();
        setLayout(new FlowLayout());
        add(board);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        pack();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new GUI();
            }
        });
    }

    class Board extends JPanel {

        public Field[][] fields = new Field[8][8];

        public Board() {
            setLayout(new GridLayout(8, 8));
            setMinimumSize(new Dimension(500, 500));
            setPreferredSize(new Dimension(550, 550));
            setBackground(Color.RED);
            fillBoard();
        }

        private void fillBoard() {
            for (int i = 0; i < 8; ++i) {
                for (int j = 0; j < 8; ++j) {
                    fields[i][j] = new Field(i, j);
                    add(fields[i][j]);
                }
            }
        }
    }

    class Field extends JLabel {

        private int x, y;

        public Field(int x, int y) {
            this.x = x;
            this.y = y;
            setOpaque(true);
            setMinimumSize(new Dimension(50, 50));
            setPreferredSize(new Dimension(75, 75));
            if ((x + y) % 2 == 0) {
                setBackground(Color.GREEN);
            } else {
                setBackground(Color.YELLOW);
            }
        }
    }
}

edited Jun 28, 2011 at 0:46

answered Jun 28, 2011 at 0:41

trashgod

206k33 gold badges264 silver badges1.1k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

trashgod Over a year ago

For reference, this is really just a picture of @Hovercraft Full Of Eels' insightful comment.

mKorbel Over a year ago

best for 2D Graphics around +1

james_bond · Accepted Answer · 2011-06-28 00:59:49Z

-1

You should set layout manager and add component to the contentPane on JFrame, inside GUI you should call:

getContentPane().setLayout(new FlowLayout());
getContentPane().add(board);

Your code compiles if both Board and Field are refactored to inner classes, but the result looks like this Result

To make the interface look without the red line comment setPreferredSize(new Dimension(550,550)); on your Board constructor so it become:

public Board(){
        int rows = 8,cols = 8;
    setLayout(new GridLayout(rows,cols));
    setMinimumSize(new Dimension(500,500));
    //setPreferredSize(new Dimension(550,550));
    setBackground(Color.RED);
    fillBoard();
}

The result after removing setPreferredSize()

edited Jun 28, 2011 at 0:59

answered Jun 28, 2011 at 0:30

james_bond

6,9163 gold badges30 silver badges39 bronze badges

4 Comments

Mark Peters Over a year ago

Calling those methods directly on the JFrame (as the OP is doing) just delegates to the content pane, this should make no difference.

james_bond Over a year ago

He didn't mention what version of jdk he was working with so my answer is not really wrong per se

Mark Peters Over a year ago

I didn't downvote, but you're absolutely right. It looks like this behaviour was added (or at least documented) starting in Java 5. But I would hope the OP isn't using a dreadfully out of date version of Java.

Piotr Chabros Over a year ago

Thanks for answer, but this didn't solve my problem. I am using the newest Java version - jre6

Collectives™ on Stack Overflow

Java layout problem

2 Answers 2

2 Comments

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related