Jpanel size not correct

Question

So I'm trying to make a Pacman-like game using swing, JFrame, and JPanel, with dimensions of 256x256; however, when I actually compile the game the screen is a bit bigger. I cant tell if it's because of not overriding a method correctly or possibly something dealing with layouts.

This is my JFrame class which adds a JPanel

*Note I have some things commented out because I was trying to figure out if they helped or not.

public class GameDevelopment extends JFrame{

//Window Stuff ... hopefully
public static final int DimensionHeight = 256;
public static final int DimensionWidth = 256;

// Level stuff possibly     
Tile startingTile;

Player player;
Walls walls;
public static Tile[][] tiles;

public GameDevelopment(){
    //Initialize           
    tiles = new Tile[DimensionWidth/16 ][DimensionHeight/16];
    for(int i = 0; i < DimensionWidth/16; i++){
        for(int y = 0; y < DimensionHeight/16; y++){
            tiles[i][y] = new Tile(i, y);
        }
    }

    startingTile = tiles[tiles.length/2][tiles[0].length/2];
    //xStart = (tiles.length/2) * 16;
    //yStart = (tiles[0].length/2) * 16;
    walls = new Walls();
    player = new Player(startingTile);


    //Sceen stuff       
    setTitle("Game");                        
    addKeyListener(player);
    addMouseListener(player);
    add(new Draw(walls, player), BorderLayout.CENTER);
    //setSize(DimensionWidth, DimensionHeight);
    pack();

    setLocationRelativeTo(null);
    setResizable(false);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setVisible(true);
}

public static void main(String[] args){
    SpriteSheet.getSprites();
    //Create tiles
    GameDevelopment game = new GameDevelopment();
}

I know if you add a component and call pack() it sets the jframe to the components sizes so I'm not sure what's the problem.

This is my Jpanel class which draws the screen. I also manually drew what the screen should look like in rectangles and the screen clearly is larger than what it's supposed to be.

*Note I pass in various classes which have draw methods and call those methods from this class using a single paintComponent, It probably isn't very well optimized but that shouldn't be the problem.

public class Draw extends JPanel{

//Size
int DimensionHeight;
int DimensionWidth;

// Components
ArrayList components;
int amount;

public Draw(DrawGraphics ... _components){
    //Size
    DimensionWidth = GameDevelopment.DimensionWidth;
    DimensionHeight = GameDevelopment.DimensionHeight;
    //this.setPreferredSize(new Dimension(256, 256));
    //setMinimumSize(new Dimension(DimensionWidth, DimensionHeight));
    //setMaximumSize(new Dimension(DimensionWidth, DimensionHeight));
    //setSize(DimensionWidth, DimensionHeight);
    setBackground(new Color(80, 0, 255));
    System.out.println(getMinimumSize());

    //Components
    components = new ArrayList();
    components.addAll(Arrays.asList(_components));
    amount = components.size();
}

@Override
public Dimension getPreferredSize(){
    return new Dimension(DimensionWidth, DimensionHeight);
}

@Override
public void paintComponent(Graphics g){
    super.paintComponent(g);
    for(int i = 0; i < 16; i++){
        for(int y = 0; y < 16; y++){
            g.drawRect(i*16, y*16, 16, 16);
        }
    }
    for(int i = 0; i < amount; i++){
        ((DrawGraphics)components.get(i)).draw(g);
    }
    //g.drawRect(0, 0, 16, 16);
    repaint();
}

As a result I get this picture, It shows some blue space after the drawn rectangles:

Thanks for helping!

Answer 1

Don't invoke repaint() in a painting method. This will result in an infinite loop.

It shows some blue space after the drawn rectangles:

    setResizable(false);
    pack();
    setLocationRelativeTo(null);
//    setResizable(false);

You need to make the frame non-resizable BEFORE you pack the frame.