Create Snake Game in Java

Create Snake Game in Java:

Snake Game in Java Sample Code:

Output:

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Random;

import javax.swing.JFrame;


public class SnakeGame extends JFrame{
	
	SnakeGame(){
		
		this.add(new GamePanel());
		this.setTitle("Snake");
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		this.setResizable(false);
		this.pack();
		this.setVisible(true);
		this.setLocationRelativeTo(null);
		
	}
	
	public class GamePanel extends JPanel implements ActionListener{

		static final int SCREEN_WIDTH = 1300;
		static final int SCREEN_HEIGHT = 750;
		static final int UNIT_SIZE = 50;
		static final int GAME_UNITS = (SCREEN_WIDTH*SCREEN_HEIGHT)/(UNIT_SIZE*UNIT_SIZE);
		static final int DELAY = 175;
		final int x[] = new int[GAME_UNITS];
		final int y[] = new int[GAME_UNITS];
		int bodyParts = 6;
		int applesEaten;
		int appleX;
		int appleY;
		char direction = 'R';
		boolean running = false;
		Timer timer;
		Random random;
		
		GamePanel(){
			random = new Random();
			this.setPreferredSize(new Dimension(SCREEN_WIDTH,SCREEN_HEIGHT));
			this.setBackground(Color.black);
			this.setFocusable(true);
			this.addKeyListener(new MyKeyAdapter());
			startGame();
		}
		public void startGame() {
			newApple();
			running = true;
			timer = new Timer(DELAY,this);
			timer.start();
		}
		public void paintComponent(Graphics g) {
			super.paintComponent(g);
			draw(g);
		}
		public void draw(Graphics g) {
			
			if(running) {
				
				g.setColor(Color.red);
				g.fillOval(appleX, appleY, UNIT_SIZE, UNIT_SIZE);
			
				for(int i = 0; i< bodyParts;i++) {
					if(i == 0) {
						g.setColor(Color.green);
						g.fillRect(x[i], y[i], UNIT_SIZE, UNIT_SIZE);
					}
					else {
						g.setColor(new Color(45,180,0));
						//g.setColor(new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255)));
						g.fillRect(x[i], y[i], UNIT_SIZE, UNIT_SIZE);
					}			
				}
				g.setColor(Color.red);
				g.setFont( new Font("ROBOTO",Font.BOLD, 40));
				FontMetrics metrics = getFontMetrics(g.getFont());
				g.drawString("Score: "+applesEaten, (SCREEN_WIDTH - metrics.stringWidth("Score: "+applesEaten))/2, g.getFont().getSize());
			}
			else {
				gameOver(g);
			}
			
		}
		public void newApple(){
			appleX = random.nextInt((int)(SCREEN_WIDTH/UNIT_SIZE))*UNIT_SIZE;
			appleY = random.nextInt((int)(SCREEN_HEIGHT/UNIT_SIZE))*UNIT_SIZE;
		}
		public void move(){
			for(int i = bodyParts;i>0;i--) {
				x[i] = x[i-1];
				y[i] = y[i-1];
			}
			
			switch(direction) {
			case 'U':
				y[0] = y[0] - UNIT_SIZE;
				break;
			case 'D':
				y[0] = y[0] + UNIT_SIZE;
				break;
			case 'L':
				x[0] = x[0] - UNIT_SIZE;
				break;
			case 'R':
				x[0] = x[0] + UNIT_SIZE;
				break;
			}
			
		}
		public void checkApple() {
			if((x[0] == appleX) && (y[0] == appleY)) {
				bodyParts++;
				applesEaten++;
				newApple();
			}
		}
		public void checkCollisions() {
			//checks if head collides with body
			for(int i = bodyParts;i>0;i--) {
				if((x[0] == x[i])&& (y[0] == y[i])) {
					running = false;
				}
			}
			//check if head touches left border
			if(x[0] < 0) {
				running = false;
			}
			//check if head touches right border
			if(x[0] > SCREEN_WIDTH) {
				running = false;
			}
			//check if head touches top border
			if(y[0] < 0) {
				running = false;
			}
			//check if head touches bottom border
			if(y[0] > SCREEN_HEIGHT) {
				running = false;
			}
			
			if(!running) {
				timer.stop();
			}
		}
		public void gameOver(Graphics g) {
			//Score
			g.setColor(Color.red);
			g.setFont( new Font("Ink Free",Font.BOLD, 40));
			FontMetrics metrics1 = getFontMetrics(g.getFont());
			g.drawString("Score: "+applesEaten, (SCREEN_WIDTH - metrics1.stringWidth("Score: "+applesEaten))/2, g.getFont().getSize());
			//Game Over text
			g.setColor(Color.red);
			g.setFont( new Font("Ink Free",Font.BOLD, 75));
			FontMetrics metrics2 = getFontMetrics(g.getFont());
			g.drawString("Game Over", (SCREEN_WIDTH - metrics2.stringWidth("Game Over"))/2, SCREEN_HEIGHT/2);
		}
		@Override
		public void actionPerformed(ActionEvent e) {
			
			if(running) {
				move();
				checkApple();
				checkCollisions();
			}
			repaint();
		}
		
		public class MyKeyAdapter extends KeyAdapter{
			@Override
			public void keyPressed(KeyEvent e) {
				switch(e.getKeyCode()) {
				case KeyEvent.VK_LEFT:
					if(direction != 'R') {
						direction = 'L';
					}
					break;
				case KeyEvent.VK_RIGHT:
					if(direction != 'L') {
						direction = 'R';
					}
					break;
				case KeyEvent.VK_UP:
					if(direction != 'D') {
						direction = 'U';
					}
					break;
				case KeyEvent.VK_DOWN:
					if(direction != 'U') {
						direction = 'D';
					}
					break;
				}
			}
		}
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		 new SnakeGame();

	
	
	}

}