Question

Recently I’ve been working on a program that paints an area with empty, colored squares. Their locations on the screen are based off of the values 1 and 2 in a text file. 1s are supposed to make red boxes, and 2s are supposed to make green boxes. However, when I run the program, only red boxes are painted. I did some testing and found out that the repaint method is only being called twice(once sometimes for some reason), even though there are close to 300 values in the file, and repaint() should be called once for every value. Here is my code:

public class MAP extends JFrame {

    public static void main(String[] args) throws IOException {
        MAP map = new MAP();
    }

    Shape shape;
    int x = -32;
    int y = 0;
    ArrayList<Shape> shapes = new ArrayList<Shape>();
    Graphics2D g2;
    Color coulor = null;

    private class PaintSurface extends JComponent {

        public PaintSurface() {
        }

        public void paint(Graphics g) {
            g2 = (Graphics2D) g;
            g2.setColor(coulor);
            for (Shape s : shapes) {
                g2.draw(s);
            }

        }
    }

    public MAP() throws FileNotFoundException, IOException {
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        frame.add(panel);
        frame.setTitle("Grid Maker");
        frame.setSize(400, 200);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.add(new PaintSurface(), BorderLayout.CENTER);
        frame.setVisible(true);

        readNextLine();
    }

    private void readNextLine() throws IOException {
        File file = new File("map.txt");
        BufferedReader in = new BufferedReader(new FileReader(file));
        String line = in.readLine();

        while (line != null) {
            for (int i = 0; i < line.length(); i++) {
                char c = line.charAt(i);
                if (c == '1') {
                    coulor = Color.RED;
                    x += 32;
                    int smallX = x / 32;
                    int smallY = y / 32;
                    shape = new Rectangle2D.Float(x, y, 32, 32);
                    shapes.add(shape);
                    repaint();
                } else if (c == '2') {
                    coulor = Color.GREEN;
                    x += 32;
                    int smallX = x / 32;
                    int smallY = y / 32;
                    shape = new Rectangle2D.Float(x, y, 32, 32);
                    shapes.add(shape);
                    repaint();

                }
            }

            line = in.readLine();
            x = -32;
            y += 32;
        }
    }
}

Why isn’t this code working properly?

Answer 1

Just to add to other answers, here is a piece of code (based on yours) which looks already a lot better (yet there are still some issues, but you are not there yet):

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.Rectangle2D;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JComponent;
import javax.swing.JFrame;

public class MAP extends JFrame {

    public static void main(String[] args) throws IOException {
        MAP map = new MAP();
    }

    public static class ColoredShape {
        private Shape shape;
        private Color color;

        public ColoredShape(Shape shape, Color color) {
            super();
            this.shape = shape;
            this.color = color;
        }

        public Shape getShape() {
            return shape;
        }

        public Color getColor() {
            return color;
        }
    }

    int x = -32;
    int y = 0;
    List<ColoredShape> shapes = new ArrayList<ColoredShape>();
    Graphics2D g2;

    private class PaintSurface extends JComponent {

        public PaintSurface() {
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g2 = (Graphics2D) g;
            for (ColoredShape s : shapes) {
                g2.setColor(s.getColor());
                g2.draw(s.getShape());
            }

        }
    }

    public MAP() throws FileNotFoundException, IOException {
        JFrame frame = new JFrame();
        frame.setTitle("Grid Maker");
        frame.setSize(400, 400);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.add(new PaintSurface(), BorderLayout.CENTER);
        frame.setVisible(true);

        readNextLine();
    }

    private void readNextLine() throws IOException {
        BufferedReader in = new BufferedReader(new StringReader("11121\n1221\n2212\n221121\n111221\n11221\n222\n2222\n"));
        String line = in.readLine();

        while (line != null) {
            for (int i = 0; i < line.length(); i++) {
                char c = line.charAt(i);
                Color color = null;
                if (c == '1') {
                    color = Color.RED;
                } else if (c == '2') {
                    color = Color.GREEN;
                }
                if (color != null) {
                    shapes.add(new ColoredShape(new Rectangle2D.Float(x, y, 32, 32), color));
                    x += 32;
                    repaint();
                }
            }

            line = in.readLine();
            x = -32;
            y += 32;
        }
    }
}