Adding Start, Stop, Reset button to simple java game

Question

I am a new coder. I am having trouble adding a start and stop button for this piece of example code that i am working off. I\'m sure i have to mess with with Th

Answer 1

This is an mcve demonstrating the structure outlined in Hovercraft Full Of Eels comment :

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.ActionListener;
import java.awt.geom.Area;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;

public class AnimationUsingTimer {

    private Timer timer;

    AnimationUsingTimer() {

        JFrame window = new JFrame();
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        AnimationPanel animationPanel = new AnimationPanel();
        window.add(animationPanel);

        JButton start = new JButton("Start");
        start.addActionListener(e -> animationPanel.start());
        window.add(start, BorderLayout.PAGE_START);

        JButton stop = new JButton("Stop");
        stop.addActionListener(e -> animationPanel.stop());
        window.add(stop, BorderLayout.PAGE_END);
        window.pack();
        window.setVisible(true);
    }

    class AnimationPanel extends JPanel{

        private BufferedImage img;
        private Area ball, walls;
        private final static int W = 450,  H = 300,  DIAMETER = 20;
        private int x = W/2,  y = H/2, xDelta = 3,  yDelta = 2;

        AnimationPanel() {
            img = new BufferedImage(W, H, BufferedImage.TYPE_INT_RGB);
            JLabel imageLabel = new JLabel(new ImageIcon(img));
            add(imageLabel);
            walls = new Area(new Rectangle(0,0,W,H));

            ActionListener animate = e -> {
                animate();
                repaint();
            };
            timer = new Timer(50, animate);
        }

        public void animate() {
            x+=xDelta;      y+=yDelta;
            ball = new Area(new Ellipse2D.Double(x, y, DIAMETER, DIAMETER));

            if (checkCollision(ball,walls)) {
                if ( x+DIAMETER>img.getWidth() || x<0 ) {
                    xDelta *= -1;
                }
                if(y+DIAMETER>img.getHeight() || y<0 ) {
                    yDelta *= -1;
                }
            }
        }

        @Override
        protected void paintComponent(Graphics g){
            super.paintComponent(g);

            Graphics2D g2D = img.createGraphics();
            g2D.setRenderingHint(
                    RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);

            g2D.setColor(Color.CYAN);
            g2D.fillRect(0, 0, img.getWidth(), img.getHeight());

            if(ball != null){
                g2D.setColor(Color.RED);
                g2D.fill(ball);
            }
            g2D.dispose();
        }

        void start(){
            timer.start();
        }

        void stop(){
            timer.stop();
        }

        private boolean checkCollision(Area area1, Area area2) {

            return area1.getBounds().intersects(area2.getBounds());
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new AnimationUsingTimer());
    }
}