循环以在单击鼠标时重复操作

Question

I am making a connect 4 game and I have that is on click as follows.

    public void mouseClicked(MouseEvent e) {
    xPos = e.getX();
    yPos = e.getY();
    this.repaint();

    x = e.getX(); 
    if(x <= 400) { 
        x = x/48; 
        System.out.println("Column number " + x);
        positions[0][0]=1;
        Component board = e.getComponent();
    }
}

I then have a method that creates a red circle on the grid as follows

    public void fillCircle(Graphics g) {
    {
        g.setColor(Color.red);
        g.fillOval(xPos,yPos,40,40);
    }
}

However only one circle appears on click and when you re-click the circle is removed and is placed in the new position.

I believe I need to include some kind of loop on the fill circle method so that it doesnt just get rid of the circle and put onew in the new location, but it leaves it there and puts a new circle in the new place?

How would I do this?

Answer 1

You need to add the positions to an ArrayList or something because you're just overriding the variables xPos and yPos when you click. We can create a Position class to hold both x and y values so we only need one ArrayList .

ArrayList<Position> positions = new ArrayList<Position>();

public void mouseClicked(MouseEvent e) {
    positions.add(new Position(e.getX(), e.getY()));

    // ...
}

And the Position class

class Position {
    public int x;
    public int y;

    public Position(int x, int y) {
        this.x = x;
        this.y = y;
    }
}

Then draw all the circles in your function

public void fillCircle(Graphics g) {
{
    g.setColor(Color.red);
    for (int i = 0; i < positions.size(); i++)
        g.fillOval(positions.get(i).x, positions.get(i).y, 40, 40);
}

Update

Include this at the very top of the file.

import java.util.ArrayList;

This will import the ArrayList library that you want to use.