gamescreen.java

利用javame开发的

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package example.fruitmachine;

import javax.microedition.lcdui.*;
import java.io.IOException;


class GameScreen
    extends Canvas
    implements CommandListener, Runnable, HttpPosterListener
{
    private final FruitMachineMIDlet midlet;
    private final HttpPoster httpPoster;
    private final Account account;
    private final Display display;
    
    private final Command changeBetCommand;
    private final Command buyCreditCommand;
    private final Command spinCommand;
    private final Command quitCommand;

    private static final int BAR = 0;
    private static final int BELL = 1;
    private static final int ORANGE = 2;
    private static final int LEMON = 3;
    private static final int PLUM = 4;
    private static final int CHERRY = 5;

    private Image[] images = new Image[6];
    private final Image holdImage;
    private Image[] holdButtonImages = new Image[3];
    private static final int wheelValues[] =
    {
        BAR, ORANGE, LEMON, PLUM, CHERRY,
        BELL, ORANGE, LEMON, PLUM, CHERRY,
        BELL, ORANGE, LEMON, PLUM, CHERRY,
        BELL, ORANGE, LEMON, PLUM, CHERRY
    };
    private static final int NUM_WHEELS = 3;
    private static final int VALUES_PER_WHEEL = wheelValues.length;

    private boolean hold[] = new boolean[NUM_WHEELS];  // initially false
    private int wheelPosition[] = new int[NUM_WHEELS];
    private int fasterTicks[] = new int[NUM_WHEELS];
    private int slowerTicks[] = new int[NUM_WHEELS];
    private int spindownTicks[] = new int[NUM_WHEELS];
    private static final int spinSpeed[] = {8, 9, 7}; // pixels/tick:full speed
    private static final int TICK_TIME_MILLIS = 100;
    private static final int SPINDOWN_STEP = 4;  // ticks at each slower speed

    // if not a new spin, can't increase bet AND hold, so have to
    // record previous bet
    private boolean newSpin = true;
    private int previousBet;

    private static final int IMAGE_SPACING = 2;  // between wheels on screen
    private static final int BORDER_SPACING = 2;   // between wheels & border
    private static final int BORDER_THICKNESS = 2;  // thickness of box
    private static final int HOLD_SPACING = 2;  // between box & hold icons
    private int imageWidth;
    private int imageHeight;
    private int wheelHeight;

    // state of animation thread
    private volatile boolean aborting = false;   // set true to exit animation
    private volatile boolean spinning = false;
    private boolean spinningFreely = false;
    private final Thread animationThread;

    // state of UI
    private volatile boolean readyForInput = true;
    private boolean quitting = false;

    // if we're animating the slowing down of the wheels because the server
    // has told us whether it was a win or loss, we save the information here
    private boolean wasWin;
    private int winAmount;
    private int updatedCredit;


    GameScreen(FruitMachineMIDlet midlet,
               HttpPoster httpPoster,
               Account account,
               Display display,
               Image barImage,
               Image bellImage,
               Image orangeImage,
               Image lemonImage,
               Image plumImage,
               Image cherryImage,
               Image holdImage,
               Image hold1Image,
               Image hold2Image,
               Image hold3Image)
    {
        this.midlet = midlet;
        this.httpPoster = httpPoster;
        this.account = account;
        this.display = display;

        images[BAR] = barImage;
        images[BELL] = bellImage;
        images[ORANGE] = orangeImage;
        images[LEMON] = lemonImage;
        images[PLUM] = plumImage;
        images[CHERRY] = cherryImage;
        this.holdImage = holdImage;
        holdButtonImages[0] = hold1Image;
        holdButtonImages[1] = hold2Image;
        holdButtonImages[2] = hold3Image;

        imageWidth = barImage.getWidth();    // assume all same size !
        imageHeight = barImage.getHeight();
        wheelHeight = wheelValues.length * imageHeight;

        changeBetCommand = new Command("Change Bet", Command.SCREEN, 3);
        addCommand(changeBetCommand);
        buyCreditCommand = new Command("Buy Credit", Command.SCREEN, 3);
        addCommand(buyCreditCommand);
        spinCommand = new Command("Spin", Command.SCREEN, 1);
        addCommand(spinCommand);
        // don't make this Command.QUIT, since we don't want it winning over
        // "Spin" !
        quitCommand = new Command("Quit", Command.SCREEN, 4);
        addCommand(quitCommand);

        setInvalidEndPositions();

        setCommandListener(this);

        animationThread = new Thread(this);
        animationThread.start();   // initially just waits for a notification
    }


    // this method is used by our animation thread
    public void run()
    {
        while (!aborting)
        {
            while (!spinning && !aborting)
            {
                try
                {
                    synchronized (this)
                    {
                        wait();
                    }
                }
                catch (InterruptedException e)
                {
                }
            }
            if (!aborting)
            {
                // we're animating; spin one step and sleep a while
                spin();
                repaint(0, 0, getWidth(), getHeight());
                try
                {
                    Thread.currentThread().sleep(TICK_TIME_MILLIS);
                }
                catch (InterruptedException e)
                {
                }
            }
        }
    }


    private void spin()
    {
        boolean endOfSpin = true;
        // this should not happen at the same time as the updates of
        // these values by other means
        synchronized (wheelPosition)
        {
            for (int i = 0; i < NUM_WHEELS; ++i)
            {
                if (! hold[i])
                {
                    if (spinningFreely)
                    {
                        endOfSpin = false;
                        stepWheel(i, spinSpeed[i]);
                    }
                    else if (fasterTicks[i] > 0)
                    {
                        endOfSpin = false;
                        stepWheel(i, spinSpeed[i]);
                        fasterTicks[i]--;
                    }
                    else if (slowerTicks[i] > 0)
                    {
                        endOfSpin = false;
                        stepWheel(i, spinSpeed[i] - 1);
                        slowerTicks[i]--;
                    }
                    else if (spindownTicks[i] > 0)
                    {
                        endOfSpin = false;
                        stepWheel(i,
                                  (spindownTicks[i] + SPINDOWN_STEP - 1) /
                                                               SPINDOWN_STEP);
                        spindownTicks[i]--;
                    }
                }
            }
        }
        if (endOfSpin)
        {
            spinning = false;
            account.setCredit(updatedCredit);
            if (wasWin)
            {
                clearHolds();
                newSpin = true;
                WinScreen.showWin(winAmount);
            }
            else
            {
                newSpin = false;
                previousBet = account.getCurrentBet();
            }
            readyForInput = true;
        }
    }


    private void stepWheel(int i, int step)
    {
        wheelPosition[i] = (wheelPosition[i] + step) % wheelHeight;
    }


    // for tidying up only
    public void abort()
    {
        aborting = true;
        synchronized (this)
        {
            notify();    // wake up our animation thread and kill it
        }
    }
    
    
    // called by the UI thread
    public void paint(Graphics g)
    {
        int width = getWidth();
        int height = getHeight();
        g.setClip(0, 0, width, height);

        // fill background with black
        g.setColor(0, 0, 0);
        g.fillRect(0, 0, width, height);

        // draw a box in yellow
        int wheelBoxWidth = imageWidth * NUM_WHEELS +
                            IMAGE_SPACING * (NUM_WHEELS - 1);
        int maxWheelBoxHeight = height - BORDER_SPACING * 2
                                   - BORDER_THICKNESS * 2
                                   - HOLD_SPACING - holdImage.getHeight() - 2;
        int wheelBoxHeight = imageHeight * 2;
        if (wheelBoxHeight > maxWheelBoxHeight)
        {
            wheelBoxHeight = maxWheelBoxHeight;  // might have to shrink it
        }
        int borderBoxWidth = wheelBoxWidth +
                            BORDER_SPACING * 2 +
                            BORDER_THICKNESS * 2;
        int borderBoxHeight = wheelBoxHeight +
                             BORDER_SPACING * 2 +
                             BORDER_THICKNESS * 2;
        int rectLeft = (width - borderBoxWidth) / 2;
        int rectTop = (height  - borderBoxHeight
                        - HOLD_SPACING - holdImage.getHeight()) / 2;
        g.setColor(255, 255, 0);
        for (int i = 0; i < BORDER_THICKNESS; ++i)
        {
            g.drawRect(rectLeft + i,
                       rectTop + i,
                       borderBoxWidth - 2 * i - 1,
                       borderBoxHeight - 2 * i - 1);
        }

        // draw hold signs if in use
        int holdTop = rectTop + borderBoxHeight + HOLD_SPACING;
        int holdLeft = rectLeft + BORDER_THICKNESS + BORDER_SPACING;
        g.setColor(255, 255, 255);
        for (int i = 0; i < NUM_WHEELS; ++ i)
        {
            int signLeft = holdLeft + i * (imageWidth + IMAGE_SPACING);
            if (hold[i])
            {
                g.drawImage(holdImage,
                            signLeft,
                            holdTop,
                            Graphics.TOP | Graphics.LEFT);
            }
            else
            {
                g.drawImage(holdButtonImages[i],
                            signLeft,
                            holdTop,
                            Graphics.TOP | Graphics.LEFT);
            }
        }

        // draw wheels
        int wheelBoxLeft = rectLeft + BORDER_THICKNESS + BORDER_SPACING;
        int wheelBoxTop = rectTop + BORDER_THICKNESS + BORDER_SPACING;
        int wheelImageTop = wheelBoxTop - (imageHeight - wheelBoxHeight/2);
        g.setClip(wheelBoxLeft, wheelBoxTop, wheelBoxWidth, wheelBoxHeight);
        for (int i = 0; i < NUM_WHEELS; ++i)
        {
            int centrePosition = wheelPosition[i] + imageHeight / 2;
            int wheelLeft = wheelBoxLeft + i * (imageWidth + IMAGE_SPACING);
            int centreImageNumber =
                (centrePosition / imageHeight) % VALUES_PER_WHEEL;
            int centreImageTopOffset = wheelImageTop +
                                             centrePosition % imageHeight;
            g.drawImage(images[wheelValues[centreImageNumber]],
                        wheelLeft,
                        centreImageTopOffset,
                        Graphics.TOP | Graphics.LEFT);
            int topImageNumber = (centreImageNumber + 1) %
                                                  wheelValues.length;
            int topImageTopOffset = centreImageTopOffset - imageHeight;
            g.drawImage(images[wheelValues[topImageNumber]],
                        wheelLeft,
                        topImageTopOffset,
                        Graphics.TOP | Graphics.LEFT);
            int bottomImageNumber = 
                (centreImageNumber + wheelValues.length - 1) %
                                                  wheelValues.length;
            int bottomImageTopOffset = centreImageTopOffset + imageHeight;