gpscanvas.java

这是编写GPS过程中涉及的源代码,希望对各位有所帮助

/*****************************************************************************

 Description: The GPSCanvas class is used to display the GPS data.
              A GPSReader is created and the connection url from the BTConnector is sent as parameter.

 Created By: Oscar Vivall 2005-06-28
 
 @file        GPSCanvas.java

 COPYRIGHT All rights reserved Sony Ericsson Mobile Communications AB 2004.
 The software is the copyrighted work of Sony Ericsson Mobile Communications AB.
 The use of the software is subject to the terms of the end-user license 
 agreement which accompanies or is included with the software. The software is 
 provided "as is" and Sony Ericsson specifically disclaim any warranty or 
 condition whatsoever regarding merchantability or fitness for a specific 
 purpose, title or non-infringement. No warranty of any kind is made in 
 relation to the condition, suitability, availability, accuracy, reliability, 
 merchantability and/or non-infringement of the software provided herein.

*****************************************************************************/

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

import javax.microedition.lcdui.game.*;
import com.nokia.mid.ui.*;

public class GPSCanvas extends Canvas implements Runnable{

    private final int WIDTH, HEIGHT;
    private MIDlet midlet;

    private String []timerTxt = new String[] {"Start", "Stop", "Reset"};
    private int timerIndex=0;
    private long timer=0; // number of seconds active.
    private String timerStr = "0:00:00";
    private boolean runTimer = false;

    private double distance = 0; // the distance in meters.
    private double minutesKm = 0;
    private double speed = 0;

    private Image numberImage = null;

    private boolean SAT_OK= false;
    private int index=0;
    
    private boolean landscapeMode = false; // The user can shoose to display the application in portrait/landscape mode
    private Image landscapeImage = null; // If landscape mode is used the graphics is painted to this image which is rotated and painted on the canvas.
    private Graphics landscapeGraphics;

    private Graphics imageGraphics;
    
    public GPSCanvas(MIDlet m){
        midlet = m;

        try{
            numberImage = Image.createImage("/res/numbers.png");
        }catch(Exception e){
            System.out.println("Failed to load number image!");
        }
        
        setFullScreenMode(true);

        WIDTH = getWidth();
        HEIGHT = getHeight();
        
        landscapeImage = Image.createImage(HEIGHT, WIDTH);
        landscapeGraphics = landscapeImage.getGraphics();
        
        GPSReader gpsReader = new GPSReader(BTConnector.url);
//        GPSReader gpsReader = new GPSReader("btspp://000A5600F776:1;authenticate=false;encrypt=false;master=true");

        Thread t = new Thread(this);
        t.start();
    }

    public void paint(Graphics g){
        g.setColor(0xFFFFFF);
        g.fillRect(0, 0, WIDTH, HEIGHT);
        g.setColor(0x000000);

        if(!landscapeMode){
            // PORTRAIT MODE
            g.drawString("Timer: ", 0, 0, 0);
            drawNumbers(timerStr, g, 0, 20);
            g.fillRect(0, 45, WIDTH, 2);

            g.drawString("Distance (m): " + String.valueOf(distance), 0, 50, 0);
            drawNumbers((int)distance, g, 0, 70);
            g.fillRect(0, 95, WIDTH, 2);

            g.drawString("Speed (km/h): " + GPSReader.SPEED_KMH_STR, 0, 100, 0);
            drawNumbers(round(speed,2), g, 0, 120);
            g.fillRect(0, 145, WIDTH, 2);

            g.drawString("minutes/km: " + String.valueOf(minutesKm), 0, 150, 0);
            drawNumbers(round(minutesKm,2), g, 0, 170);
            g.fillRect(0, 195, WIDTH - 40, 2);
            g.fillRect(WIDTH - 40, 180, 2, 17);
            g.fillRect(WIDTH - 40, 180, 40, 2);

            g.drawString(GPSReader.NUM_SATELITES + " : " + GPSReader.NUM_SATELITES_STR, WIDTH/2-3, HEIGHT, Graphics.LEFT | Graphics.BOTTOM);
        }else{
            // LANDSCAPE MODE
            landscapeGraphics.setColor(0xFFFFFF);
            landscapeGraphics.fillRect(0, 0, HEIGHT, WIDTH);
            landscapeGraphics.setColor(0x000000);

            landscapeGraphics.drawString("Timer: ", 0, 0, 0);
            drawNumbers(timerStr, landscapeGraphics, 0, 20);
            landscapeGraphics.fillRect(0, 45, HEIGHT, 2);

            landscapeGraphics.drawString("Distance (m): " + String.valueOf(distance), 0, 50, 0);
            drawNumbers((int)distance, landscapeGraphics, 0, 70);
            landscapeGraphics.fillRect(0, 95, HEIGHT, 2);

            landscapeGraphics.drawString("Speed (km/h):", 0, 100, 0);
            landscapeGraphics.drawString("minutes/km:", HEIGHT/2, 100, 0);
            drawNumbers(speed, landscapeGraphics, 0, 120);
            drawNumbers(minutesKm, landscapeGraphics, HEIGHT/2, 120);
            landscapeGraphics.fillRect(0, 145, HEIGHT, 2);

            landscapeGraphics.drawString(GPSReader.NUM_SATELITES + " : " + GPSReader.NUM_SATELITES_STR, HEIGHT/2-3, WIDTH, Graphics.LEFT | Graphics.BOTTOM);
        }

        if(!landscapeMode){
            g.drawString("Exit", 0, HEIGHT, Graphics.LEFT | Graphics.BOTTOM);
            g.drawString(timerTxt[timerIndex], WIDTH, HEIGHT-15, Graphics.RIGHT | Graphics.BOTTOM);
            g.drawString(timerTxt[2], WIDTH, HEIGHT, Graphics.RIGHT | Graphics.BOTTOM);
        }else{
            landscapeGraphics.drawString("Exit", 0, WIDTH, Graphics.LEFT | Graphics.BOTTOM);
            landscapeGraphics.drawString(timerTxt[timerIndex], HEIGHT, WIDTH-13, Graphics.RIGHT | Graphics.BOTTOM);
            landscapeGraphics.drawString(timerTxt[2], HEIGHT, WIDTH, Graphics.RIGHT | Graphics.BOTTOM);

            g.drawRegion(landscapeImage, 0, 0, HEIGHT, WIDTH, Sprite.TRANS_ROT270, 0, 0, 0);
        }

    }

    // Draw the numbers image.
    private void drawNumbers(int number, Graphics g, int x, int y){
        String num = String.valueOf(number);
        int tmp;
        for(int i=0; i<num.length(); i++){
            try{
                tmp = Integer.parseInt(num.substring(i, i+1));
                g.drawRegion(numberImage, tmp*20, 0, 20, 20, 0, x+(20*i), y, 0);
            }catch(Exception e){}
        }
    }

    private void drawNumbers(double number, Graphics g, int x, int y){
        String num = String.valueOf(number);
        int tmp;
        for(int i=0; i<num.length(); i++){
            try{
                tmp = Integer.parseInt(num.substring(i, i+1));
                g.drawRegion(numberImage, tmp*20, 0, 20, 20, 0, x+(20*i), y, 0);
            }catch(Exception e){
                g.setColor(0x067606);
                g.fillRect(i*20+8 + x, y+16, 4, 4);
                g.setColor(0x000000);
            }
        }
    }

    private void drawNumbers(String num, Graphics g, int x, int y){
        int tmp;
        for(int i=0; i<num.length(); i++){
            try{
                tmp = Integer.parseInt(num.substring(i, i+1));
                g.drawRegion(numberImage, tmp*20, 0, 20, 20, 0, x+(20*i), y, 0);
            }catch(Exception e){
                g.setColor(0x067606);
                g.fillRect(i*20+8, y+16, 4, 4);
                g.setColor(0x000000);
            }
        }
    }

    public void keyPressed(int key){
        switch(key){
            case 49:
                break;
            case 50:
                break;
            case -6: // Left soft button
                midlet.notifyDestroyed();
                break;
            case -7: // Right soft button
                switch(timerIndex){
                    case 0:
                        runTimer = true;
                        break;
                    case 1:
                        runTimer = false;
                        break;
                }
                timerIndex = timerIndex==1?0:timerIndex+1;
                break;
            case -8: // 'C' button
                timer=0;
                timerStr = "0:00:00";
                break;
            case 42: // Reset the calculated distance by pressing the star key
                distance = 0;
                break;
            case 35: // Pound key to change tha appearance.
                landscapeMode ^=true;
                break;
        }
    }

    // Method to calculate the travelled distance from the current speed
    private double calculateDistance(long startTime){
        long stopTime = System.currentTimeMillis();
        long totTime = stopTime - startTime;

        double speed1 = (speed/3600) *1000; // m/s
        double dist = speed1 * ((double)totTime/1000D);
        return dist;
    }

    // Method for removing decimals
    public double round(double d, int decimals){
        String s = String.valueOf(d);
        int pos = s.indexOf('.');
        if(pos==-1){
            return d;
        }
        if(s.length()>decimals+pos){
            s = s.substring(0, pos + decimals);
        }
        return Double.parseDouble(s);
// --------------------------------------------
//        double first = (int)d;
//        double next = d - first;
//        String s = String.valueOf(next);
//
//        s = s.substring(2, s.length());
//
//        if(s.length()>decimals){
//            s = s.substring(0, 2);
//        }
//
//        s = "0." + s;
//        next = Double.parseDouble(s);
//        return first + next;
    }
    
    public void run() {

        int h=0,m=0,s=0;

        long ptime = System.currentTimeMillis()/1000;
        long distTime = System.currentTimeMillis();

        long startTime = 0;

        String secStr = "", minStr = "";

        while(true){
            if(runTimer){
                if(ptime!=System.currentTimeMillis()/1000){
                    timer ++;
                    ptime = System.currentTimeMillis()/1000;

                    h = (int)timer/3600;
                    m = (int)(timer%3600)/60;
                    s = (int)timer%60;

                    secStr = s<10?"0":"";
                    minStr = m<10?"0":"";

                    timerStr = h + ":" + minStr +  m + ":" + secStr + s;
                }
            }

            index++;
            SAT_OK = false;
            if(GPSReader.NUM_SATELITES>2){
                SAT_OK = true;
                speed = GPSReader.SPEED_KMH;

                try{
                    minutesKm = round((1000 / ((GPSReader.SPEED_KMH * 1000) / 3600))/60, 2);
                }catch(Exception e){}
            }
            distance += calculateDistance(distTime);
            distTime = System.currentTimeMillis();

            repaint();
            try{
                Thread.sleep(100);
            }catch(Exception e){}
        }
    }
   
}