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我想知道如何将图像添加到下面的容器中,以将其设置为我的背景图像。该图像称为 Bg.gif,可以由 Netbeans 访问,但我只是不知道如何将其放入容器中。

最伟大的帮助!

import java.awt.Canvas;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferStrategy;
import java.util.ArrayList;

import javax.swing.JFrame;
import javax.swing.JPanel;

/**
 * The main hook of our game. This class with both act as a manager
 * for the display and central mediator for the game logic. 
 * 
 * Display management will consist of a loop that cycles round all
 * entities in the game asking them to move and then drawing them
 * in the appropriate place. With the help of an inner class it
 * will also allow the player to control the main ship.
 * 
 * As a mediator it will be informed when entities within our game
 * detect events (e.g. alient killed, played died) and will take
 * appropriate game actions.
 * 
 * @author Kristian Rice
 */
public class Game extends Canvas {
    /** The stragey that allows us to use accelerate page flipping */
    private BufferStrategy strategy;
    /** True if the game is currently "running", i.e. the game loop is looping */
    private boolean gameRunning = true;
/** The list of all the entities that exist in our game */
    private ArrayList entities = new ArrayList();
/** The list of entities that need to be removed from the game this loop */
private ArrayList removeList = new ArrayList();
/** The entity representing the player */
private Entity ship;
/** The speed at which the player's ship should move (pixels/sec) */
private double moveSpeed = 300;
/** The time at which last fired a shot */
private long lastFire = 0;
/** The interval between our players shot (ms) */
private long firingInterval = 60;
/** The number of aliens left on the screen */
private int alienCount;

/** The message to display which waiting for a key press */
private String message = "";
/** True if we're holding up game play until a key has been pressed */
private boolean waitingForKeyPress = true;
/** True if the left cursor key is currently pressed */
private boolean leftPressed = false;
/** True if the right cursor key is currently pressed */
private boolean rightPressed = false;
/** True if we are firing */
private boolean firePressed = false;
/** True if game logic needs to be applied this loop, normally as a result of a game event */
private boolean logicRequiredThisLoop = false;

    //Image background = Toolkit.getDefaultToolkit().createImage("sprites/Bg.gif");
/**
 * Construct our game and set it running.
 */
public Game() {
    // create a frame to contain our game
    JFrame container = new JFrame("Space Invaders Mod");

    // get hold the content of the frame and set up the resolution of the game
    JPanel panel = (JPanel) container.getContentPane();
    panel.setPreferredSize(new Dimension(this.getMaximumSize()));
    panel.setLayout(null);
    // setup our canvas size and put it into the content of the frame
    setBounds(0,0,800,600);
    panel.add(this);
    // Tell AWT not to bother repainting our canvas since we're
    // going to do that our self in accelerated mode
    setIgnoreRepaint(true);

    // finally make the window visible 
    container.pack();
    container.setResizable(true);
    container.setVisible(true);


    // add a listener to respond to the user closing the window. If they
    // do we'd like to exit the game
    container.addWindowListener(new WindowAdapter() {
                    @Override
        public void windowClosing(WindowEvent e) {
            System.exit(0);
        }
    });
    // add a key input system (defined below) to our canvas
    // so we can respond to key pressed
    addKeyListener(new KeyInputHandler());

    // request the focus so key events come to us
    requestFocus();

    // create the buffering strategy which will allow AWT
    // to manage our accelerated graphics
    createBufferStrategy(2);
    strategy = getBufferStrategy();

    // initialise the entities in our game so there's something
    // to see at startup
    initEntities();
}


/**
 * Start a fresh game, this should clear out any old data and
 * create a new set.
 */
private void startGame() {
    // clear out any existing entities and intialise a new set
    entities.clear();
    initEntities();

    // blank out any keyboard settings we might currently have
    leftPressed = false;
    rightPressed = false;
    firePressed = false;
}

/**
 * Initialise the starting state of the entities (ship and aliens). Each
 * entitiy will be added to the overall list of entities in the game.
 */
private void initEntities() {
    // create the player ship and place it roughly in the center of the screen
    ship = new ShipEntity(this,"sprites/ship.gif",370,550);
    entities.add(ship);  

    // create a block of aliens (5 rows, by 12 aliens, spaced evenly)
    alienCount = 0;
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien8 = new AlienEntity(this,"sprites/alien8.gif",100+(x*50),(00)+row*30);
            entities.add(alien8);
            alienCount++;
        }
                            }
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien7 = new AlienEntity(this,"sprites/alien7.gif",100+(x*50),(20)+row*30);
            entities.add(alien7);
            alienCount++;
        }
                            }
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien6 = new AlienEntity(this,"sprites/alien6.gif",100+(x*50),(40)+row*30);
            entities.add(alien6);
            alienCount++;
        }
                            }
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien5 = new AlienEntity(this,"sprites/alien5.gif",100+(x*50),(60)+row*30);
            entities.add(alien5);
            alienCount++;
        }
                            }
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien4 = new AlienEntity(this,"sprites/alien4.gif",100+(x*50),(80)+row*30);
            entities.add(alien4);
            alienCount++;
        }
                            }
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien3 = new AlienEntity(this,"sprites/alien3.gif",100+(x*50),(100)+row*30);
            entities.add(alien3);
            alienCount++;
        }
                            }
            for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien2 = new AlienEntity(this,"sprites/alien2.gif",100+(x*50),(120)+row*30);
            entities.add(alien2);
            alienCount++;
        }
    }
    for (int row=0;row<1;row++) {
        for (int x=0;x<12;x++) {
            Entity alien = new AlienEntity(this,"sprites/alien.gif",100+(x*50),(140)+row*30);
            entities.add(alien);
            alienCount++;
        }
    }System.out.println(alienCount);
}

/**
 * Notification from a game entity that the logic of the game
 * should be run at the next opportunity (normally as a result of some
 * game event)
 */
public void updateLogic() {
    logicRequiredThisLoop = true;
}

/**
 * Remove an entity from the game. The entity removed will
 * no longer move or be drawn.
 * 
 * @param entity The entity that should be removed
 */
public void removeEntity(Entity entity) {
    removeList.add(entity);
}

/**
 * Notification that the player has died. 
 */
public void notifyDeath() {
    message = "Oh no! They got you, try again?";
    waitingForKeyPress = true;
}

/**
 * Notification that the player has won since all the aliens
 * are dead.
 */
public void notifyWin() {
    message = "Well done! You Win!";
    waitingForKeyPress = true;
}

/**
 * Notification that an alien has been killed
 */
public void notifyAlienKilled() {
    // reduce the alient count, if there are none left, the player has won!
    alienCount--;

    if (alienCount == 0) {
        notifyWin();
    }

    // if there are still some aliens left then they all need to get faster, so
    // speed up all the existing aliens
    for (int i=0;i<entities.size();i++) {
        Entity entity = (Entity) entities.get(i);

        if (entity instanceof AlienEntity) {
            // speed up by 2%
            entity.setHorizontalMovement(entity.getHorizontalMovement() * 1.02);
        }
    }
}

/**
 * Attempt to fire a shot from the player. Its called "try"
 * since we must first check that the player can fire at this 
 * point, i.e. has he/she waited long enough between shots
 */
public void tryToFire() {
    // check that we have waiting long enough to fire
    if (System.currentTimeMillis() - lastFire < firingInterval) {
        return;
    }

    // if we waited long enough, create the shot entity, and record the time.
    lastFire = System.currentTimeMillis();
    ShotEntity shot = new ShotEntity(this,"sprites/shot.gif",ship.getX()+10,ship.getY()-30);
    entities.add(shot);
}

/**
 * The main game loop. This loop is running during all game
 * play as is responsible for the following activities:
 * <p>
 * - Working out the speed of the game loop to update moves
 * - Moving the game entities
 * - Drawing the screen contents (entities, text)
 * - Updating game events
 * - Checking Input
 * <p>
 */
public void gameLoop() {
    long lastLoopTime = System.currentTimeMillis();

    // keep looping round til the game ends
    while (gameRunning) {
        // work out how long its been since the last update, this
        // will be used to calculate how far the entities should
        // move this loop
        long delta = System.currentTimeMillis() - lastLoopTime;
        lastLoopTime = System.currentTimeMillis();

        // Get hold of a graphics context for the accelerated 
        // surface and blank it out
        Graphics2D g = (Graphics2D) strategy.getDrawGraphics();
        g.setColor(Color.black);
        g.fillRect(0,0,super.getWidth(),super.getHeight());
        //g.drawImage(background, 0,0, null);
        // cycle round asking each entity to move itself
        if (!waitingForKeyPress) {
            for (int i=0;i<entities.size();i++) {
                Entity entity = (Entity) entities.get(i);

                entity.move(delta);
            }
        }

        // cycle round drawing all the entities we have in the game
        for (int i=0;i<entities.size();i++) {
            Entity entity = (Entity) entities.get(i);

            entity.draw(g);
        }

        // brute force collisions, compare every entity against
        // every other entity. If any of them collide notify 
        // both entities that the collision has occured
        for (int p=0;p<entities.size();p++) {
            for (int s=p+1;s<entities.size();s++) {
                Entity me = (Entity) entities.get(p);
                Entity him = (Entity) entities.get(s);

                if (me.collidesWith(him)) {
                    me.collidedWith(him);
                    him.collidedWith(me);
                }
            }
        }

        // remove any entity that has been marked for clear up
        entities.removeAll(removeList);
        removeList.clear();

        // if a game event has indicated that game logic should
        // be resolved, cycle round every entity requesting that
        // their personal logic should be considered.
        if (logicRequiredThisLoop) {
            for (int i=0;i<entities.size();i++) {
                Entity entity = (Entity) entities.get(i);
                entity.doLogic();
            }

            logicRequiredThisLoop = false;
        }

        // if we're waiting for an "any key" press then draw the 
        // current message 
        if (waitingForKeyPress) {
            g.setColor(Color.white);
            g.drawString(message,(800-g.getFontMetrics().stringWidth(message))/2,250);
            g.drawString("Press any key",(800-g.getFontMetrics().stringWidth("Press any key"))/2,300);
        }

        // finally, we've completed drawing so clear up the graphics
        // and flip the buffer over
        g.dispose();
        strategy.show();

        // resolve the movement of the ship. First assume the ship 
        // isn't moving. If either cursor key is pressed then
        // update the movement appropraitely
        ship.setHorizontalMovement(0);

        if ((leftPressed) && (!rightPressed)) {
            ship.setHorizontalMovement(-moveSpeed);
        } else if ((rightPressed) && (!leftPressed)) {
            ship.setHorizontalMovement(moveSpeed);
        }

        // if we're pressing fire, attempt to fire
        if (firePressed) {
            tryToFire();
        }

        // finally pause for a bit. Note: this should run us at about
        // 100 fps but on windows this might vary each loop due to
        // a bad implementation of timer
        try { Thread.sleep(10); } catch (Exception e) {}
    }
}

/**
 * A class to handle keyboard input from the user. The class
 * handles both dynamic input during game play, i.e. left/right 
 * and shoot, and more static type input (i.e. press any key to
 * continue)
 * 
 * This has been implemented as an inner class more through 
 * habbit then anything else. Its perfectly normal to implement
 * this as seperate class if slight less convienient.
 * 
 * @author Kevin Glass
 */
private class KeyInputHandler extends KeyAdapter {
    /** The number of key presses we've had while waiting for an "any key" press */
    private int pressCount = 1;

    /**
     * Notification from AWT that a key has been pressed. Note that
     * a key being pressed is equal to being pushed down but *NOT*
     * released. Thats where keyTyped() comes in.
     *
     * @param e The details of the key that was pressed 
     */
    public void keyPressed(KeyEvent e) {
        // if we're waiting for an "any key" typed then we don't 
        // want to do anything with just a "press"
        if (waitingForKeyPress) {
            return;
        }


        if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            leftPressed = true;
        }
        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            rightPressed = true;
        }
        if (e.getKeyCode() == KeyEvent.VK_SPACE) {
            firePressed = true;
        }
    } 

    /**
     * Notification from AWT that a key has been released.
     *
     * @param e The details of the key that was released 
     */
            @Override
    public void keyReleased(KeyEvent e) {
        // if we're waiting for an "any key" typed then we don't 
        // want to do anything with just a "released"
        if (waitingForKeyPress) {
            return;
        }

        if (e.getKeyCode() == KeyEvent.VK_LEFT) {
            leftPressed = false;
        }
        if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
            rightPressed = false;
        }
        if (e.getKeyCode() == KeyEvent.VK_SPACE) {
            firePressed = false;
        }
    }

    /**
     * Notification from AWT that a key has been typed. Note that
     * typing a key means to both press and then release it.
     *
     * @param e The details of the key that was typed. 
     */
            @Override
    public void keyTyped(KeyEvent e) {
        // if we're waiting for a "any key" type then
        // check if we've recieved any recently. We may
        // have had a keyType() event from the user releasing
        // the shoot or move keys, hence the use of the "pressCount"
        // counter.
        if (waitingForKeyPress) {
            if (pressCount == 1) {
                // since we've now recieved our key typed
                // event we can mark it as such and start 
                // our new game
                waitingForKeyPress = false;
                startGame();
                pressCount = 0;
            } else {
                pressCount++;
            }
        }

        // if we hit escape, then quit the game
        if (e.getKeyChar() == 27) {
            System.exit(0);
        }
    }
}

/**
 * The entry point into the game. We'll simply create an
 * instance of class which will start the display and game
 * loop.
 * 
 * @param argv The arguments that are passed into our game
 */
public static void main(String argv[]) {
    Game g =new Game();

    // Start the main game loop, note: this method will not
    // return until the game has finished running. Hence we are
    // using the actual main thread to run the game.
    g.gameLoop();
}

}

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1 回答 1

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这很容易愚蠢的大脑!添加一个 var img,调用它并告诉它在哪里可以找到它。简单!!!

于 2013-09-15T12:50:22.660 回答