JPanel Possibly Overlapping?

Question

So I have this problem with my code. Whenever I load up the game there is a red square in the center of the screen, and I have not programmed it to do so. I have tried to find the error for hours but I just can't see it. I think it has to do with the panels or something. The second thing is that when I press the button to draw the grid, only a small line appears. It is programmed to be much bigger than what it is, and it is not in the right location either. Below is all my code, and any help is greatly appreciated!!

package com.theDevCorner;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenuBar;
import javax.swing.JPanel;

public class Game extends JPanel implements ActionListener {

   public static JButton grid = new JButton("Show Grid");

   public static JPanel drawArea = new JPanel();
   public static JMenuBar menu = new JMenuBar();
   public static JPanel notDrawn = new JPanel();

   public static boolean gridPressed = false;

   public Game() {

      grid.addActionListener(this);

   }

   public static void main(String args[]) {
      Game game = new Game();

      JFrame frame = new JFrame();
      frame.setVisible(true);
      frame.setSize(new Dimension(
            Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit
                  .getDefaultToolkit().getScreenSize().height));
      frame.setTitle("Game");
      frame.setAlwaysOnTop(true);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setResizable(false);

      menu.setSize(new Dimension(1600, 20));
      menu.setLocation(0, 0);

      notDrawn.setBackground(new Color(255, 0, 50));
      notDrawn.setSize(100, 900);
      notDrawn.add(grid);
      notDrawn.setLayout(null);

      grid.setSize(new Dimension(100, 25));
      grid.setLocation(0, 25);

      drawArea.setSize(new Dimension((Toolkit.getDefaultToolkit()
            .getScreenSize().width), Toolkit.getDefaultToolkit()
            .getScreenSize().height));
      drawArea.setLocation(100, 0);
      drawArea.setBackground(Color.black);
      drawArea.add(menu);
      drawArea.add(game);

      frame.add(drawArea);
      frame.add(notDrawn);

   }

   public void paint(Graphics g) {

      Game game = new Game();

      if (gridPressed) {

         Game.drawGrid(0, 0, g);

      }

      g.dispose();
      repaint();

   }

   public static void drawGrid(int x, int y, Graphics g) {

      g.setColor(Color.white);
      g.drawLine(x, y, 50, 300);

   }

   @Override
   public void actionPerformed(ActionEvent e) {

      if (e.getSource() == grid && gridPressed == true) {
         gridPressed = false;
         System.out.println("Unpressed");
      }

      if (e.getSource() == grid) {
         gridPressed = true;

         System.out.println("Pressed");
      }
   }
}

Answer 1

There are a number of problems...

The red "square" you are seeing is actually your grid button. The reason it's red is because of your paint method.

Graphics is a shared resource, that is, each component that is painted on the screen shares the same Graphics context. Because you chose to dispose of the context and because you've failed to honor the paint chain, you've basically screwed it up.

Don't EVER dispose of a Graphics context you didn't create. It will prevent anything from being painted to it again. Always call super.paintXxx. The paint chain is complex and does a lot of very important work. If you're going to ignore it, be ready to have to re-implement it.

null layouts are vary rarely the right choice, especially when you're laying out components. You need to separate your components from your custom painting, otherwise the components will appear above the custom painting.

This frame.setSize(new Dimension(Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit.getDefaultToolkit().getScreenSize().height)) is not the way to maximize a window. This does not take into consideration the possibility of things like tasks bars. Instead use Frame#setExtendedState

As Andreas has already commented, you actionPerformed logic is wrong. You should be using an if-statement or simply flipping the boolean logic...

Updated with simple example

ps- static is not your friend here...

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Game extends JPanel implements ActionListener {

    private GridPane gridPane;

    public Game() {
        setLayout(new BorderLayout());

        SideBarPane sideBar = new SideBarPane();
        sideBar.addActionListener(this);
        add(sideBar, BorderLayout.WEST);

        gridPane = new GridPane();
        add(gridPane);
    }

    public static void main(String args[]) {
        Game game = new Game();

        JFrame frame = new JFrame();
        frame.setVisible(true);
        frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        frame.setTitle("Game");
        frame.setAlwaysOnTop(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        frame.setLayout(new BorderLayout());
        frame.add(game);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equalsIgnoreCase("grid")) {
            gridPane.setGridOn(!gridPane.isGridOn());
        }
    }

    public class GridPane extends JPanel {

        private boolean gridOn = false;

        public GridPane() {
            setBackground(Color.BLACK);
        }

        public boolean isGridOn() {
            return gridOn;
        }

        public void setGridOn(boolean value) {
            if (value != gridOn) {
                this.gridOn = value;
                repaint();
            }
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (gridOn) {
                g.setColor(Color.white);
                g.drawLine(0, 0, 50, 300);
            }
        }
    }

    public class SideBarPane extends JPanel {

        public JButton grid;

        public SideBarPane() {
            setBackground(new Color(255, 0, 50));
            setLayout(new GridBagLayout());
            grid = new JButton("Show Grid");
            grid.setActionCommand("grid");
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.anchor = GridBagConstraints.NORTH;
            gbc.weighty = 1;
            add(grid, gbc);
        }

        public void addActionListener(ActionListener listener) {
            grid.addActionListener(listener);
        }
    }
}