btcanvas.java

J2ME程序源代码。实现手机通过蓝牙技术连接到GPS Receiver

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

 Description: This canvas class is used to display the Bluetooth devices available for connection.
              The BT connector class is used to get available deivices.

 Created By: Oscar Vivall 2005-06-28
 
 @file        BTCanvas.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.bluetooth.*;
import java.util.*;

public class BTCanvas extends Canvas implements Runnable{

    private MIDlet midlet;
    private BTConnector btConnect; // class used to get the bluetooth devices.

    private boolean active = true; // active while thread is running.

    private Vector devices; // A vector with the devices received form the BTConnector.
    private String []deviceNames; // An array with the device names

    private int index=-1; // Keep track of the bluetooth device that is selected.
    private int midIndex;

    private final int WIDTH, HEIGHT; // Height and width of the canvas.

    // used for the connection animation
    private boolean connecting = false;
    private int connectX = 10;
    
    // Used for the device searching animation
    private int searchAnimDeg = 0;
    private float []sinTable = new float[640];

    public BTCanvas(MIDlet m){
        midlet = m;
        setFullScreenMode(true);

        // Create the sinus table that are used for the searching animation.
        for(int i=0; i<640; i++){
            sinTable[i] = (float)Math.sin(Math.toRadians((double)i)) * 5;
        }
        
        WIDTH = getWidth();
        HEIGHT = getHeight();
        connectX = WIDTH/2 - 40;
        
        midIndex= ((HEIGHT-20)/20)/2;
        System.out.println("midIndex=" + midIndex);
        
        btConnect = new BTConnector();
        devices = btConnect.getDevices();
        
        
        Thread t = new Thread(this);
        t.setPriority(Thread.MAX_PRIORITY);
        t.start();
    }

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

        deviceNames = btConnect.getDeviceNames();
        
        // Display all the devices that are found by the BTConnector.
        if(!connecting){
            for(int i=0; i<btConnect.getSize(); i++){
                int offset = 0;
                if(btConnect.getSize()*20 > HEIGHT - 40){
                    if(index > midIndex){
                        offset = (index-midIndex)*20;
                    }
                }
                if(i==index){
                    g.setColor(0x00FF00);
                    g.drawString(deviceNames[i], 0, 20 + i*20 - offset, 0);
                    g.setColor(0x000000);
                }else{
                    g.drawString(deviceNames[i], 0, 20 + i*20 - offset, 0);
                }
            }

            g.setColor(0xFFFFFF);
            g.fillRect(0, 0, WIDTH, 20);
            g.setColor(0x000000);
            g.drawString("Bluetooth Devices found...", 0, 0, Graphics.LEFT | Graphics.TOP);

            // Paint a little animation while searching for devices.
            if(!btConnect.doneSearchingDevices()){
                searchAnimDeg = searchAnimDeg>=360?searchAnimDeg-360:searchAnimDeg+5;
                int centerX = WIDTH - 15; 
                int centerY = 7; 
                int x1 = (int)sinTable[searchAnimDeg] +centerX;
                int y1 = (int)sinTable[searchAnimDeg+90] + centerY;
                int x2 = (int)sinTable[searchAnimDeg + 180] + centerX;
                int y2 = (int)sinTable[searchAnimDeg + 180 +90] + centerY;
                g.drawLine(x1, y1, x2, y2);
            }

            g.fillRect(0, 15, WIDTH, 2);

            g.setColor(0xFFFFFF);
            g.fillRect(0, HEIGHT-20, WIDTH, 20);
            g.setColor(0x000000);

            g.fillRect(0, HEIGHT-18, WIDTH, 2);
            g.drawString("Exit", 0, HEIGHT, Graphics.LEFT | Graphics.BOTTOM);
            g.drawString("Connect...", WIDTH, HEIGHT, Graphics.RIGHT | Graphics.BOTTOM);

        // Paint a connecting animation when searching for a bluetooth service.
        }else{
            g.drawString("Connecting...", WIDTH/2-40, HEIGHT/2-12, Graphics.LEFT | Graphics.BOTTOM);
            g.drawRect(WIDTH/2-40, HEIGHT/2-10, 80, 20);
            g.fillRect(connectX, HEIGHT/2-10, 5, 20);
            connectX = connectX >=WIDTH/2+40?WIDTH/2-45:connectX+1;

            g.setColor(0xFFFFFF);
            g.fillRect(WIDTH/2-45, HEIGHT/2-10, 5, 21);
            g.fillRect(WIDTH/2+41, HEIGHT/2-10, 5, 21);
            g.setColor(0x000000);

            g.drawString("Exit", 0, HEIGHT, Graphics.LEFT | Graphics.BOTTOM);
            g.drawString("Back...", WIDTH, HEIGHT, Graphics.RIGHT | Graphics.BOTTOM);
        }
    }

    public void keyPressed(int key){
        switch(key){
            case -1:
                index = index > 0?index-1:index;
                break;
            case -2:
                index = index < btConnect.getSize()-1?index+1:index;
                break;
            case -3:
                break;
            case -4:
                break;
            case -6: // Left soft key, used to exit the midlet
                midlet.notifyDestroyed();
                break;
            case -7: // Right soft key is used to connect to a device or to start a new search.
                if(!connecting && index != -1){
                    btConnect.connect(index);
                    connecting = true;
                }else if(connecting){
                    index = -1;
                    connecting = false;
                    btConnect.startSearch();
                }
                break;
        }
    }

    public void run(){

        while(active){
            repaint();

            // If a connection do a device is completed and a bt service is found
            if(btConnect.doneSearchingServices() && btConnect.getUrl().compareTo("") != 0){
                active = false;
            }
            
            try{
                Thread.sleep(10);
            }catch(Exception e){}
        }
        
        // Open a new canvas and start the gps reading.
        GPS gps = (GPS)midlet;
        gps.startGPS();
    }
    
}