import java.awt.*; import java.awt.event.*; import java.util.ArrayList; import java.util.Random; import javax.swing.*; public class Board extends JPanel implements ActionListener, KeyListener { // controls the delay between each tick in ms private final int DELAY = 25; // controls the size of the board public static final int TILE_SIZE = 50; public static final int ROWS = 12; public static final int COLUMNS = 18; // controls how many coins appear on the board public static final int NUM_COINS = 5; // suppress serialization warning private static final long serialVersionUID = 490905409104883233L; // keep a reference to the timer object that triggers actionPerformed() in // case we need access to it in another method private Timer timer; // objects that appear on the game board private Player player; private ArrayList coins; public Board() { // set the game board size setPreferredSize(new Dimension(TILE_SIZE * COLUMNS, TILE_SIZE * ROWS)); // set the game board background color setBackground(new Color(232, 232, 232)); // initialize the game state player = new Player(); coins = populateCoins(); // this timer will call the actionPerformed() method every DELAY ms timer = new Timer(DELAY, this); timer.start(); } @Override public void actionPerformed(ActionEvent e) { // this method is called by the timer every DELAY ms. // use this space to update the state of your game or animation // before the graphics are redrawn. // prevent the player from disappearing off the board player.tick(); // give the player points for collecting coins collectCoins(); // calling repaint() will trigger paintComponent() to run again, // which will refresh/redraw the graphics. repaint(); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); // when calling g.drawImage() we can use "this" for the ImageObserver // because Component implements the ImageObserver interface, and JPanel // extends from Component. So "this" Board instance, as a Component, can // react to imageUpdate() events triggered by g.drawImage() // draw our graphics. drawBackground(g); drawScore(g); for (Coin coin : coins) { coin.draw(g, this); } player.draw(g, this); // this smooths out animations on some systems Toolkit.getDefaultToolkit().sync(); } @Override public void keyTyped(KeyEvent e) { // this is not used but must be defined as part of the KeyListener interface } @Override public void keyPressed(KeyEvent e) { // react to key down events player.keyPressed(e); } @Override public void keyReleased(KeyEvent e) { // react to key up events } private void drawBackground(Graphics g) { // draw a checkered background g.setColor(new Color(214, 214, 214)); for (int row = 0; row < ROWS; row++) { for (int col = 0; col < COLUMNS; col++) { // only color every other tile if ((row + col) % 2 == 1) { // draw a square tile at the current row/column position g.fillRect( col * TILE_SIZE, row * TILE_SIZE, TILE_SIZE, TILE_SIZE ); } } } } private void drawScore(Graphics g) { // set the text to be displayed String text = "$" + player.getScore(); // we need to cast the Graphics to Graphics2D to draw nicer text Graphics2D g2d = (Graphics2D) g; g2d.setRenderingHint( RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON); g2d.setRenderingHint( RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); g2d.setRenderingHint( RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON); // set the text color and font g2d.setColor(new Color(30, 201, 139)); g2d.setFont(new Font("Lato", Font.BOLD, 25)); // draw the score in the bottom center of the screen // https://stackoverflow.com/a/27740330/4655368 FontMetrics metrics = g2d.getFontMetrics(g2d.getFont()); // the text will be contained within this rectangle. // here I've sized it to be the entire bottom row of board tiles Rectangle rect = new Rectangle(0, TILE_SIZE * (ROWS - 1), TILE_SIZE * COLUMNS, TILE_SIZE); // determine the x coordinate for the text int x = rect.x + (rect.width - metrics.stringWidth(text)) / 2; // determine the y coordinate for the text // (note we add the ascent, as in java 2d 0 is top of the screen) int y = rect.y + ((rect.height - metrics.getHeight()) / 2) + metrics.getAscent(); // draw the string g2d.drawString(text, x, y); } private ArrayList populateCoins() { ArrayList coinList = new ArrayList<>(); Random rand = new Random(); // create the given number of coins in random positions on the board. // note that there is not check here to prevent two coins from occupying the same // spot, nor to prevent coins from spawning in the same spot as the player for (int i = 0; i < NUM_COINS; i++) { int coinX = rand.nextInt(COLUMNS); int coinY = rand.nextInt(ROWS); coinList.add(new Coin(coinX, coinY)); } return coinList; } private void collectCoins() { // allow player to pickup coins ArrayList collectedCoins = new ArrayList<>(); for (Coin coin : coins) { // if the player is on the same tile as a coin, collect it if (player.getPos().equals(coin.getPos())) { // give the player some points for picking this up player.addScore(100); collectedCoins.add(coin); } } // remove collected coins from the board coins.removeAll(collectedCoins); } }