在Java中的2D网格数组中绘制圆

Question

I understand how to make 2d array grid. I experimented to put random numbers in it but i do not know how to draw them on jframe. For instance, 0 for red circle , 1 for green circle and so on. I need to figure out how represent them in grid manner too.

public class Game {


    public static void initGrid(){
        //clumn and row 4 x 4
        int col = 4;
        int row = 4;

        //initialize 2d grid array
        int[][] a = new int[row][col];

        Random rand = new Random();

        //for loop to fill it with random number
        for(int x = 0 ; x < col ; x++) {
            for(int y = 0; y < row; y++) {
                a[x][y] = (int) rand.nextInt(4);
                System.out.print(a[x][y]);
            }//inner for
            System.out.println();
        }//outer for


    }//method


    public static void main(String[] args){
        initGrid();
    }


}

I understand JFrame and JPanel as far as drawing on empty canvas but not the way i want. I want to combine both code but my knowledge is limited.

    import java.awt.Color;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.RenderingHints;
    import java.awt.geom.Ellipse2D;
    import javax.swing.JFrame;
    import javax.swing.JPanel;

  @SuppressWarnings("serial")
  public class Game2 extends JPanel{

    @Override
    public void paint(Graphics g){
        Graphics2D g2d = (Graphics2D) g;
        g2d.setColor(Color.RED);
        g2d.fillOval(0, 0, 30, 30);
        g2d.drawOval(0, 50, 30, 30);
        g2d.fillRect(50, 0, 30, 30);
        g2d.drawRect(50, 50, 30, 30);

        g2d.draw(new Ellipse2D.Double(0, 100, 30 ,30));
    }

     public static void main(String[] args){
        JFrame frame = new JFrame("Mini Tennis");
        frame.add(new Game2());
        frame.setSize(300, 300);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
} 

Answer 1

My suggestion is:

1. Pass the Game class as a parameter to the constructor of Game2 and store it as a local variable in the Game2 class as illustrated below:

    Game game; public Game2(Game game){ this.game = game; //Rest of your constructor. } 

2. Next you declare a getter method in the Game class to retrieve the array which stores the position grid like as below:

    public int[][] getPositions(){ return this.a; } 

3. Create a method that will return the colour to paint based on the int value stored as the element of the grid like this:

    private Color getColor(int col){ switch(col){ case 0: return Color.red; case 1: . . . . } } 

4. Now instead of overriding the paint method of your Game2 class override the paintComponent and draw the circles in the paintComponent method as illustrated(Here I have considered the circles to be of 30px diameter with a gap of 20px between them):

    public void paintComponent(Graphics g){ super.paintComponent(g); Graphics2D g2d = (Graphics2D) g; int[][] pos = this.game.getPositions(); for(int i = 0; i < pos.length; i++){ for(int j = 0; j < pos[i].length; j++){ g2d.setColor(getColor(pos[i][j])); g2d.fillOval(i*50, j*50, 30, 30); } } } 

I hope this will solve your problem of accessing the Game representing the model from the Game2 class representing the view.