stopwatchcanvas.java

J2ME MIDP_Example_Applications

//
// Copyright ? 2002 Nokia Corporation.
//
// THIS SOURCE CODE IS PROVIDED 'AS IS', WITH NO WARRANTIES WHATSOEVER,
// EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY, FITNESS
// FOR ANY PARTICULAR PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE
// OR TRADE PRACTICE, RELATING TO THE SOURCE CODE OR ANY WARRANTY OTHERWISE
// ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE AND WITH NO
// OBLIGATION OF NOKIA TO PROVIDE THE LICENSEE WITH ANY MAINTENANCE OR
// SUPPORT. FURTHERMORE, NOKIA MAKES NO WARRANTY THAT EXERCISE OF THE
// RIGHTS GRANTED HEREUNDER DOES NOT INFRINGE OR MAY NOT CAUSE INFRINGEMENT
// OF ANY PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OWNED OR CONTROLLED
// BY THIRD PARTIES
//
// Furthermore, information provided in this source code is preliminary,
// and may be changed substantially prior to final release. Nokia Corporation
// retains the right to make changes to this source code at any time,
// without notice. This source code is provided for informational
// purposes only.

//
// Nokia and Nokia Connecting People are registered trademarks of Nokia
// Corporation. Java and all Java-based marks are trademarks or registered
// trademarks of Sun Microsystems, Inc. Other product and company names
// mentioned herein may be trademarks or trade names of their respective owners.

// A non-exclusive, non-transferable, worldwide, limited license is hereby
// granted to the Licensee to download, print, reproduce and modify the
// source code. The licensee has the right to market, sell, distribute and
// make available the source code in original or modified form only when
// incorporated into the programs developed by the Licensee. No other
// license, express or implied, by estoppel or otherwise, to any other
// intellectual property rights is granted herein.
//


package example.stopwatch;

import javax.microedition.lcdui.*;
import java.util.Random;


class StopwatchCanvas
    extends Canvas
    implements CommandListener, Runnable
{
    private static final int DIGIT_INTERVAL = 1;
    private static final int DOT_SIZE = 3;

    private static final int[] base = {10, 1000, 60000, 3600000};
    private static final Image[][] digitImage;
    private static final int digitWidth, digitHeight;
    private static final Image labelImage;

    private final Command startCommand;
    private final Command continueCommand;
    private final Command stopCommand;
    private final Command resetCommand;
    private final Command quitCommand;
    private final int[] digit = new int[4];
    private final StopwatchMIDlet parent;
    private final int labelY, dotY;
    private final int width, height;
    private final int panelX, panelY;

    private Thread thread = null;
    private long startTime = 0;
    private long remainingTime = 0;
    private volatile boolean startPressed = false;


    static
    {
        Image fontImage = loadImage("/font.png");
        digitWidth = fontImage.getWidth() / 10;
        digitHeight = fontImage.getHeight() / 2;

        digitImage = new Image[10][2];
        for (int i=0; i<10; i++)
        {
            for (int k=0; k<2; k++)
            {
                digitImage[i][k] = Image.createImage(digitWidth, digitHeight);
                Graphics gDigit = digitImage[i][k].getGraphics();
                gDigit.drawImage(fontImage,
                                 -i * digitWidth,
                                 -k * digitHeight,
                                 Graphics.TOP|Graphics.LEFT);
            }
        }
        labelImage = loadImage("/label.png");
    }


    StopwatchCanvas(StopwatchMIDlet parent)
    {
        this.parent = parent;
        width = getWidth();
        height = getHeight();
        panelX = (width - (8 * digitWidth) - (4 * DIGIT_INTERVAL) -
                 (3 * DOT_SIZE)) / 2;
        panelY = ((height - digitHeight) / 2) + 4;

        dotY = panelY + digitHeight - DOT_SIZE;
        labelY = panelY - labelImage.getHeight() - 8;

        quitCommand = new Command("Quit", Command.EXIT, 2);
        addCommand(quitCommand);

        startCommand = new Command("Start", Command.SCREEN, 1);
        addCommand(startCommand);
        stopCommand = new Command("Stop", Command.SCREEN, 1);
        resetCommand = new Command("Reset", Command.SCREEN, 1);
        continueCommand = new Command("Continue", Command.SCREEN, 1);
        setCommandListener(this);
    }


    void start()
    {
        thread = new Thread(this);
        thread.start();
    }


    void stop()
    {
        thread = null;
    }


    public void run()
    {
        Thread currentThread = Thread.currentThread();

        while (currentThread == thread)
        {
            if (startPressed)
            {
                updateTime();

                // One could check isShown() here, to only repaint
                // and service repaints when the canvas is shown,
                // and not when it is hidden by some system screen.
                repaint(panelX-2, labelY,
                        width - panelX - panelX + 5,
                        height - labelY - labelY + 4);
                serviceRepaints();
            }


            try
            {
                synchronized(this)
                {
                    // The split time is measured in 100ths of a second.
                    // 0.01 seconds is 10 milliseconds. The wait
                    // should therefore be at most a few milliseconds.

                    wait(1); // wait one millisecond
                }
            }
            catch (InterruptedException e)
            {
            }
        }
    }


    private void updateTime()
    {
        long elapsedTime = System.currentTimeMillis() - startTime +
                           remainingTime;

        for (int i=3; i>=0; i--)
        {
            digit[i] = (int)(elapsedTime / base[i]);
            elapsedTime %= base[i];
        }
    }


    public void paint(Graphics g)
    {
        // Paint the entire canvas
        g.setColor(255, 255, 255);
        g.fillRect(0, 0, getWidth(), getHeight());
        drawFrame(g);
        drawDigits(g);
    }


    private void drawDigits(Graphics g)
    {
        for (int i=0; i<4; i++)
        {
            // update both (2) digits for hh mm ss nn
            for (int k=0; k < 2; k++)
            {
                int index = (k == 0) ? digit[i]%10 : digit[i]/10;
                int fontType = i > 0 ? 0 : 1;

                int digitX = width - panelX - (((i*2)+k+1)*digitWidth) -
                             ((i*2)+k+1)/(2*DIGIT_INTERVAL) - (i*DOT_SIZE);

                g.drawImage(digitImage[index][fontType], digitX, panelY,
                            Graphics.TOP|Graphics.LEFT);
            }
            // draw dots
            if (i < 2)
            {
                int dotX = panelX + (i+1) * (2*digitWidth + DIGIT_INTERVAL) +
                       i*DOT_SIZE + 1;
                g.fillRect(dotX, dotY, DOT_SIZE, DOT_SIZE);
            }
        }
    }


    private void drawFrame(Graphics g)
    {
        g.setColor(0, 0, 0);
        g.drawImage(labelImage, panelX-2, labelY, Graphics.TOP|Graphics.LEFT);
        g.drawRoundRect(panelX-2, panelY-4, width-panelX*2+4, digitHeight+8,
                        4, 4);
    }


    public void commandAction(Command c, Displayable d)
    {
        if ((c == startCommand) || (c == continueCommand))
        {
            startTime = System.currentTimeMillis();

            removeCommand(startCommand);
            removeCommand(continueCommand);
            removeCommand(resetCommand);
            addCommand(stopCommand);

            remainingTime = 0;
            for (int i=0; i<4; i++)
            {
                remainingTime += digit[i] * base[i];
            }

            setStartPressed(true);
        }
        else if (c == stopCommand)
        {
            // The accuracy of using stopCommand to time an event to
            // 100ths of a second, might be affected by how commands are
            // implemented in a MIDP device. For example, navigating a menu
            // of commands to select the stop command takes time, which
            // might affect the ability to time an event accurately. Therefore,
            // a second stop mechanism is also provided, using the
            // FIRE button (see method keyPressed).

            handleStop();
        }
        else if (c == resetCommand)
        {
            remainingTime = 0;

            removeCommand(resetCommand);
            removeCommand(continueCommand);
            addCommand(startCommand);

            // update and repaint zeroed digits
            for (int i=0; i<4; i++)
            {
                digit[i] = 0;
            }

            repaint(panelX-2, labelY,
                    width - panelX - panelX + 5,
                    height - labelY - labelY + 4);
            serviceRepaints();
        }
        else
        {
            parent.quit();
        }
    }


    private void handleStop()
    {
        setStartPressed(false);

        removeCommand(stopCommand);
        addCommand(continueCommand);
        addCommand(resetCommand);
    }


    private synchronized void setStartPressed(boolean bool)
    {
        startPressed = bool;
    }


    static Image loadImage(String imageFile)
    {
        Image image = null;
        try
        {
            image = Image.createImage(imageFile);
        }
        catch (Exception e)
        {
            // use null image
        }
        return image;
    }
}