Thread: How do I delete an object from my program?

So I have this bit of code, not complete but can give you complete code if needed, and so far, it makes a few shapes which is great and all but I need it to delete shapes on request. I want to make a brick game and basically I will edit this code so the ball bounces off the walls and hits bricks but before I do this I want to know how to at the very least know how to delete these shapes that I made so I can then use that code to practice making a brick game that will delete multiple elements.

Long story short, I want to know how to make the squares disappear. The only thing I've heard so far is to set what I want equal to NULL, but I'm not sure how to do it.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package bouncing.ball;
 
/**
 *
 * @author Marlin
 */
import javax.swing.*;
import java.awt.*;
 
public class BouncePanel extends JPanel {
 
    //location of bouncing ball
    private int x;
    private int y;
    private int dx = 5;
    private int dy = 5;
 
    BouncePanel() {
        x = 100;
        y = 50;
 
        AnimationThread animethread = new AnimationThread(this);
        animethread.start();
    }
 
    public void paintComponent(Graphics g) {
        //first, clear screen
        super.paintComponent(g);
 
        g.drawLine(10, 20, 300, 200);
        g.drawRect(100, 100, 50, 70);
 
        g.setColor(Color.BLUE);
        g.fillOval(x, y, 40, 40);
    }
 
    public void update() throws InterruptedException {
 
        dy += 1;
        x += dx;
        y += dy;
 
 
        if (x < 0) {
            x = 0;
            dx = -dx;
        }
 
        if (x + 40 >= getWidth()) {
            dx = -dx;
        }
 
        if (y < 0) {
            y = 0;
            dy = -dy;
        }
 
        if (y + 40 >= getHeight()) {
            dy = -dy;
        }
 
        repaint();
    }
}

g.drawLine(10, 20, 300, 200);
        g.drawRect(100, 100, 50, 70);
 
        g.setColor(Color.BLUE);
        g.fillOval(x, y, 40, 40);

it's only these lines that are using the paint method.

inside the middle section of each (parameters) you will see 4 numbers (integers, x and y are also integers (variables)).
Try to comment out the
//g.drawRect(100, 100, 50, 70);

Originally Posted by macko

Try to comment out the
//g.drawRect(100, 100, 50, 70);

Well, it's not that easy. I could comment it out but I want to get rid of it mid game. Not during compilation.

So in order to have the shapes drawn, I have to have them drawn every cycle and if I tell it to skip the statement then it will erase it? What if I wanted to draw multiple blocks that will erase when I hit them? How will I do that?

all I want to do is make shapes at the top of the screen and make a paddle with a ball at the bottom and every time the ball hits the paddle and it hits the block the block disappears.

Would it be possible for me to put those shapes in an array so i don't have to write if statements for each and every one?