External Bluetooth GNSS Receiver

BluetoothGPSService.java (Service to parse Bluetooth Data)
package com.stesalitsystems.sxbluetooth.bluetooth;
//Created by STESALIT SYSTEMS LIMITED

import android.app.Service;
import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences; import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager; import android.location.LocationProvider; import android.os.Build;
import android.os.Bundle; import android.os.IBinder; import android.os.SystemClock;
import android.support.annotation.Nullable;
import android.support.v4.content.LocalBroadcastManager; import android.text.TextUtils;
import android.util.Log;

import com.stesalitsystems.sxbluetooth.R;

import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream;
import java.io.InputStreamReader; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Locale;
import java.util.TimeZone; import java.util.Timer; import java.util.TimerTask; import java.util.UUID;
import java.util.regex.Matcher;

import java.util.regex.Pattern;
/**
Created by Krishnendu Dasgupta on 01-04-2019.
*/
public class BluetoothGPSService extends Service{private BluetoothAdapter btAdapter=null;
private BluetoothSocket btSocket=null; private static final String LOG_TAG=”T55″;
private static final UUID MY_UUID=UUID.fromString(“00001101-0000-1000-8000-00805F9B34FB”);

// MAC-address of Bluetooth module public String newAddress=null; SharedPreferences pref;
private Timer timer;
private TimerTask timerTask; InputStream tmpIn=null; boolean enabled;
boolean ready=true; TextUtils.SimpleStringSplitter splitter;
public static final String GPS_MOCK_PROVIDER=”gps”; String fixTime=””;
private float precision=10f; boolean read_pubx=false; @Nullable
@Override
public IBinder onBind(Intent intent){return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId){
pref=getApplicationContext().getSharedPreferences(getResources().getString(R.string.pref_key), 0); String service_status=pref.getString(“address”, “”);
newAddress=pref.getString(“address”, “”); btAdapter=BluetoothAdapter.getDefaultAdapter();
BluetoothDevice device=btAdapter.getRemoteDevice(newAddress);

//Attempt to create a bluetooth socket for comms try{
btSocket=device.createRfcommSocketToServiceRecord(MY_UUID);
}catch (IOException e1){e1.printStackTrace();
}
// Establish the connection. try{
btSocket.connect();
enabled=true;
}catch (IOException e){e.printStackTrace();
try{enabled=false;
btSocket.close();//If IO exception occurs attempt to close socket
}catch (IOException e2){enabled=false; e2.printStackTrace();
}
}
if(enabled){startTimer();
}
return START_STICKY;
}
public void startTimer(){
//set a new Timer timer=new Timer();
//initialize the TimerTask’s job initializeTimerTask();
//schedule the timer, to wake up every 1 second timer.schedule(timerTask, 2000, 2000); //
}

public void initializeTimerTask(){timerTask=new TimerTask(){public void run(){
try{
if (pref.getBoolean(“iserviceStarted”, true)){
//Service Should Start tmpIn=btSocket.getInputStream(); try{
BufferedReader reader=new BufferedReader(new InputStreamReader(tmpIn,”US-ASCII”)); String s;
long now=SystemClock.uptimeMillis(); long lastRead=now;
while((enabled) && (now < lastRead+5000 )){if (reader.ready()){
s=reader.readLine();
Log.v(LOG_TAG, “data: “+ System.currentTimeMillis()+” “+s); parseNmeaSentence1(s+”\r\n”);
if(read_pubx){
Location loc=parsePUBX(s+”\r\n”); if(loc==null){
sendMessageToActivity(loc,”false”,getApplicationContext());
}else{sendMessageToActivity(loc,”true”,getApplicationContext());
}
}

ready=true;
lastRead=SystemClock.uptimeMillis();
}else{
Log.d(LOG_TAG, “data: not ready “+ System.currentTimeMillis()); SystemClock.sleep(500);
}
now=SystemClock.uptimeMillis();
}
}catch (IOException e){e.printStackTrace();
Log.e(LOG_TAG, “error while getting data”, e);
}finally{
// cleanly closing everything…
}
}
}catch (Exception e){
//Some exception e.printStackTrace();
}
}
};
}
private static void sendMessageToActivity(Location l, String msg, Context context){Intent intent=new Intent(“GPSLocationUpdates”);
// You can also include some extra data. intent.putExtra(“Status”, msg);
Bundle b=new Bundle(); b.putParcelable(“Location”, l); intent.putExtra(“Location”, b);
LocalBroadcastManager.getInstance(context).sendBroadcast(intent);
}
public Location parsePUBX(String pubx){String nmeaSentence=null;
Pattern xx=Pattern.compile(“\\$([^*$]*)\\*([0-9A-F][0-9A-F])?\r\n”); Matcher m=xx.matcher(pubx);

if (m.matches()){nmeaSentence=m.group(0); String sentence=m.group(1); String checkSum=m.group(2);
Log.v(LOG_TAG, “data: ” + System.currentTimeMillis() + ” ” + sentence + ” cheksum; ” + checkSum + ” control: ” + String.format(“%X”, computeChecksum(sentence)));
splitter=new TextUtils.SimpleStringSplitter(‘,’); splitter.setString(sentence);
String command=splitter.next(); if (command.equals(“PUBX”)){String msgId=splitter.next(); String strTime=splitter.next();
String lat=splitter.next(); //ddmm.mmmmm String ns=splitter.next();
String lon=splitter.next(); //ddmm.mmmmm

String ew=splitter.next(); String altRef=splitter.next(); String sat=splitter.next(); if(sat==”NF”)
sat=”No Fix”; if(sat==”DR”)
sat=”Dead reckoning only solution”; if(sat==”G2″)
sat=”Stand alone 2D solution”; if(sat==”G3″)
sat=”Stand alone 3D solution”; if(sat==”D2″) sat=”Differential 2D solution”; if(sat==”D3″) sat=”Differential 3D solution”; if(sat==”RK”)
sat=”Combined GPS + dead reckoning solution”; if(sat==”TT”)
sat=”Time only solution”;

String hAcc=splitter.next(); //Horizontal accuracy estimate in meter
String vAcc=splitter.next(); //Vertical accuracy estimat in meter
String SOG=splitter.next();//Speed over ground(Km/Hr)
String COG=splitter.next();//Course over ground in degree
String vVel=splitter.next(); //Vertical velocity (positive downwards)
String diffAge=splitter.next(); //Age of differential corrections (blank when DGPS is not used)
String hdop=splitter.next();
String vdop=splitter.next();
String tdop=splitter.next(); //TDOP, Time Dilution of Precision
String numSvs=splitter.next(); //Number of satellites used in the navigation solution
String reserved=splitter.next(); //Reserved, always set to 0
String dr=splitter.next(); //DR used
Location fix=new Location(GPS_MOCK_PROVIDER); if (! strTime.equals(fixTime)){
fix=new Location(GPS_MOCK_PROVIDER); fixTime=strTime;
long fixTimestamp=parseNmeaTime(strTime); fix.setTime(fixTimestamp);
}
if (lat !=null && !lat.equals(“”)){fix.setLatitude(parseNmeaLatitude(lat,ns));
}
if (lon !=null && !lon.equals(“”)){fix.setLongitude(parseNmeaLongitude(lon,ew));
}
if (hAcc !=null && !hAcc.equals(“”)){fix.setAccuracy(Float.parseFloat(hAcc));
}
if (altRef !=null && !altRef.equals(“”)){fix.setAltitude(Double.parseDouble(altRef));
}
if (SOG !=null && !SOG.equals(“”)){fix.setSpeed(Float.parseFloat(SOG));
}
long fixTimestamp=parseNmeaTime(strTime); fix.setTime(fixTimestamp);
fix.setElapsedRealtimeNanos(fixTimestamp); return fix;
}
}
return null;
}
public Location parseNmeaSentence1(String gpsSentence){String nmeaSentence=null;
Pattern xx=Pattern.compile(“\\$([^*$]*)\\*([0-9A-F][0-9A-F])?\r\n”); Matcher m=xx.matcher(gpsSentence);

if (m.matches()){nmeaSentence=m.group(0); String sentence=m.group(1); String checkSum=m.group(2);
Log.v(LOG_TAG, “data: “+ System.currentTimeMillis()+” “+sentence+” cheksum; “+checkSum +” control: “+ String.format(“%X”,computeChecksum(sentence)));
splitter=new TextUtils.SimpleStringSplitter(‘,’); splitter.setString(sentence);
String command=splitter.next(); if (command.equals(“GNGGA”)){
/* $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47

Where:
GGAGlobal Positioning System Fix Data
123519 Fix taken at 12:35:19 UTC
4807.038,N Latitude 48 deg 07.038′ N
01131.000,E Longitude 11 deg 31.000′ E
Fix quality: 0=invalid
1=GPS fix (SPS)
=DGPS fix
=PPS fix
=Real Time Kinematic
=Float RTK
=estimated (dead reckoning) (2.3 feature)
=Manual input mode
=Simulation mode
08Number of satellites being tracked
0.9Horizontal dilution of position
545.4,MAltitude, Meters, above mean sea level
46.9,MHeight of geoid (mean sea level) above WGS84 ellipsoid
(empty field) time in seconds since last DGPS update (empty field) DGPS station ID number
*47the checksum data, always begins with *

*/
// UTC time of fix HHmmss.S String time=splitter.next();
// latitude ddmm.M String lat=splitter.next();
// direction (N/S)
String latDir=splitter.next();
// longitude dddmm.M String lon=splitter.next();
// direction (E/W)
String lonDir=splitter.next();
/* fix quality:
0=invalid
1=GPS fix (SPS)
2=DGPS fix 3=PPS fix
4=Real Time Kinematic 5=Float RTK
6=estimated (dead reckoning) (2.3 feature) 7=Manual input mode
=Simulation mode
*/
String quality=splitter.next();
// Number of satellites being tracked String nbSat=splitter.next();
// Horizontal dilution of position (float) String hdop=splitter.next();
// Altitude, Meters, above mean sea level String alt=splitter.next();
// Height of geoid (mean sea level) above WGS84 ellipsoid String geoAlt=splitter.next();
// time in seconds since last DGPS update
// DGPS station ID number
if (quality !=null && !quality.equals(“”) && !quality.equals(“0”) ){Location fix=new Location(GPS_MOCK_PROVIDER);
if (! time.equals(fixTime)){fixTime=time;
long fixTimestamp=parseNmeaTime(time); fix.setTime(fixTimestamp);
Log.v(LOG_TAG, “Fix: “+fix);
}
if (lat !=null && !lat.equals(“”)){fix.setLatitude(parseNmeaLatitude(lat,latDir));
}
if (lon !=null && !lon.equals(“”)){fix.setLongitude(parseNmeaLongitude(lon,lonDir));
}
if (hdop !=null && !hdop.equals(“”)){fix.setAccuracy(Float.parseFloat(hdop)*precision);
}
if (alt !=null && !alt.equals(“”)){
fix.setAltitude(Double.parseDouble(alt));
}
long fixTimestamp=parseNmeaTime(time); fix.setTime(fixTimestamp);
if (nbSat !=null && !nbSat.equals(“”)){Bundle extras=new Bundle();
extras.putInt(“satellites”, Integer.parseInt(nbSat)); fix.setExtras(extras);
}
fix.setElapsedRealtimeNanos(fixTimestamp);
return fix;
}
else if(quality.equals(“0”)){return null;
}
}else if (command.equals(“GNRMC”)){
/* $GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A
Where:
RMCRecommended Minimum sentence C
123519 Fix taken at 12:35:19 UTC
A Status A=active or V=Void.
4807.038,N Latitude 48 deg 07.038′ N
01131.000,E Longitude 11 deg 31.000′ E
022.4Speed over the ground in knots
084.4 Track angle in degrees True
230394 Date – 23rd of March 1994
003.1,W Magnetic Variation
*6AThe checksum data, always begins with *
*/
// UTC time of fix HHmmss.S String time=splitter.next();
// fix status (A/V)
String status=splitter.next();
// latitude ddmm.M String lat=splitter.next();
// direction (N/S)
String latDir=splitter.next();
// longitude dddmm.M String lon=splitter.next();
// direction (E/W)
String lonDir=splitter.next();
// Speed over the ground in knots String speed=splitter.next();
// Track angle in degrees True String bearing=splitter.next();
// UTC date of fix DDMMYY String date=splitter.next();
// Magnetic Variation ddd.D

String magn=splitter.next();
// Magnetic variation direction (E/W) String magnDir=splitter.next();
// for NMEA 0183 version 3.00 active the Mode indicator field is added
// Mode indicator, (A=autonomous, D=differential, E=Estimated, N=not valid, S=Simulator ) if (status !=null && !status.equals(“”) && status.equals(“A”) ){
read_pubx=true;
Location fix=null;
if (! time.equals(fixTime)){
fix=new Location(GPS_MOCK_PROVIDER); fixTime=time;
long fixTimestamp=parseNmeaTime(time); fix.setTime(fixTimestamp);
}
if (lat !=null && !lat.equals(“”)){fix.setLatitude(parseNmeaLatitude(lat,latDir));
}
if (lon !=null && !lon.equals(“”)){fix.setLongitude(parseNmeaLongitude(lon,lonDir));
}
if (speed !=null && !speed.equals(“”)){fix.setSpeed(parseNmeaSpeed(speed, “N”));
}
if (bearing !=null && !bearing.equals(“”)){fix.setBearing(Float.parseFloat(bearing));
}
fix.setAccuracy(5f);
long fixTimestamp=parseNmeaTime(time); fix.setElapsedRealtimeNanos(fixTimestamp);
return fix;
}else if(status.equals(“V”)){read_pubx=false;
return null;
}
}else if (command.equals(“GPGSA”)){
/* $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39
Where:
GSASatellite status
A Auto selection of 2D or 3D fix (M=manual)
3 3D fix – values include: 1=no fix
2=2D fix
3=3D fix
04,05… PRNs of satellites used for fix (space for 12)
2.5PDOP (Position dilution of precision)
1.3Horizontal dilution of precision (HDOP)
2.1Vertical dilution of precision (VDOP)

*39the checksum data, always begins with *
*/
// mode : A Auto selection of 2D or 3D fix / M=manual String mode=splitter.next();
// fix type : 1 – no fix / 2 – 2D / 3 – 3D String fixType=splitter.next();
// discard PRNs of satellites used for fix (space for 12) for (int i=0 ; ((i<12)&&(! “1”.equals(fixType))) ; i++){splitter.next();
}
// Position dilution of precision (float) String pdop=splitter.next();
// Horizontal dilution of precision (float) String hdop=splitter.next();
// Vertical dilution of precision (float) String vdop=splitter.next();
}else if (command.equals(“GPVTG”)){
/* $GPVTG,054.7,T,034.4,M,005.5,N,010.2,K*48
where:
VTGTrack made good and ground speed
054.7,T True track made good (degrees)
034.4,MMagnetic track made good
005.5,NGround speed, knots
010.2,KGround speed, Kilometers per hour
*48Checksum
*/
// Track angle in degrees True String bearing=splitter.next();
// T splitter.next();
// Magnetic track made good String magn=splitter.next();
// M splitter.next();
// Speed over the ground in knots String speedKnots=splitter.next();
// N splitter.next();
// Speed over the ground in Kilometers per hour String speedKm=splitter.next();
// K splitter.next();
// for NMEA 0183 version 3.00 active the Mode indicator field is added
// Mode indicator, (A=autonomous, D=differential, E=Estimated, N=not valid, S=Simulator )
}else if (command.equals(“GPGLL”)){
/* $GPGLL,4916.45,N,12311.12,W,225444,A,*1D

Where:
GLLGeographic position, Latitude and Longitude
4916.46,N Latitude 49 deg. 16.45 min. North
12311.12,W Longitude 123 deg. 11.12 min. West
225444 Fix taken at 22:54:44 UTC
A Data Active or V (void)
*iDchecksum data
*/
// latitude ddmm.M String lat=splitter.next();
// direction (N/S)
String latDir=splitter.next();
// longitude dddmm.M String lon=splitter.next();
// direction (E/W)
String lonDir=splitter.next();
// UTC time of fix HHmmss.S String time=splitter.next();
// fix status (A/V)
String status=splitter.next();
// for NMEA 0183 version 3.00 active the Mode indicator field is added
// Mode indicator, (A=autonomous, D=differential, E=Estimated, N=not valid, S=Simulator )
}else if (command.equals(“GPGSV”)){
}
}else{
}
return null;
}
public double parseNmeaLatitude(String lat, String orientation){double latitude=0.0;
if (lat !=null && orientation !=null && !lat.equals(“”) && !orientation.equals(“”)){double temp1=Double.parseDouble(lat);
double temp2=Math.floor(temp1/100); double temp3=(temp1/100 – temp2)/0.6; if (orientation.equals(“S”)){
latitude=-(temp2+temp3);
}else if (orientation.equals(“N”)){latitude=(temp2+temp3);
}
Log.e(“latitude=”,latitude+””);
}
return latitude;
}
public double parseNmeaLongitude(String lon, String orientation){double longitude=0.0;
if (lon !=null && orientation !=null && !lon.equals(“”) && !orientation.equals(“”)){double temp1=Double.parseDouble(lon);
double temp2=Math.floor(temp1/100);
double temp3=(temp1/100 – temp2)/0.6; if (orientation.equals(“W”)){
longitude=-(temp2+temp3);
}else if (orientation.equals(“E”)){longitude=(temp2+temp3);
}
Log.e(“longitude=”,longitude+””);
}
return longitude;
}
public float parseNmeaSpeed(String speed, String metric){float meterSpeed=0.0f;
if (speed !=null && metric !=null && !speed.equals(“”) && !metric.equals(“”)){float temp1=Float.parseFloat(speed)/3.6f;
if (metric.equals(“K”)){meterSpeed=temp1;
}else if (metric.equals(“N”)){meterSpeed=temp1*1.852f;
}
}
return meterSpeed;
}
public long parseNmeaTime(String time){long timestamp=0;
SimpleDateFormat fmt=new SimpleDateFormat(“HHmmss.SSS”); fmt.setTimeZone(TimeZone.getTimeZone(“GMT”));
try{
if (time !=null && time !=null){
long now=System.currentTimeMillis();
long today=now – (now %86400000L);
long temp1;
// sometime we don’t have millisecond in the time string, so we have to reformat it
temp1=fmt.parse(String.format((Locale)null,”%010.3f”, Double.parseDouble(time))).getTime(); long temp2=today+temp1;
// if we’re around midnight we could have a problem… if (temp2 – now > 43200000L){
timestamp=temp2 – 86400000L;
}else if (now – temp2 > 43200000L){timestamp=temp2 + 86400000L;
}else{
timestamp=temp2;
}
}
}catch (ParseException e){
Log.e(LOG_TAG, “Error while parsing NMEA time”, e);
}
return timestamp;
}
public byte computeChecksum(String s){byte checksum=0;
for (char c : s.toCharArray()){checksum ^=(byte)c;
}
return checksum;
}
}

Step 2: Create a background service

DeviceListActivity.java (To list paired devices and connect)

package com.stesalitsystems.sxbluetooth.bluetooth;
/**
* Created by STESALIT SYSTEMS LIMITED
*/
import android.app.AlertDialog; import android.app.AppOpsManager;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.stesalitsystems.sxbluetooth.MainActivity;
import com.stesalitsystems.sxbluetooth.R;
import java.io.IOException;
import java.util.List;
import java.util.Set;
import java.util.UUID;

public class DeviceListActivity extends AppCompatActivity{
// textview for connection status TextView textConnectionStatus;
ListView pairedListView;
//An EXTRA to take the device MAC to the next activity public static String EXTRA_DEVICE_ADDRESS;
private TextView tv_toolbar;
// Member fields
private BluetoothAdapter mBtAdapter;
private ArrayAdapter mPairedDevicesArrayAdapter; SharedPreferences pref;
private static final UUID MY_UUID=UUID.fromString(“00001101-0000-1000-8000-00805F9B34FB”);@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_device_list);
pref=this.getSharedPreferences(getResources().getString(R.string.pref_key), 0);
boolean loginStatus=pref.getBoolean(“isOn”,false);
textConnectionStatus=(TextView) findViewById(R.id.connecting);
textConnectionStatus.setTextSize(40);
FloatingActionButton btn_refresh=(FloatingActionButton)findViewById(R.id.btn_refresh);
btn_refresh.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
Intent i=new Intent(DeviceListActivity.this, DeviceListActivity.class); startActivity(i);
finish();
}
});
// Initialize array adapter for paired devices
mPairedDevicesArrayAdapter=new ArrayAdapter(this, R.layout.row_device);

// Find and set up the ListView for paired devices pairedListView=(ListView) findViewById(R.id.paired_devices);
pairedListView.setOnItemClickListener(mDeviceClickListener);
pairedListView.setAdapter(mPairedDevicesArrayAdapter);
Toolbar toolbar=(Toolbar) findViewById(R.id.toolbar);
tv_toolbar=(TextView)findViewById(R.id.tv_toolbar);
tv_toolbar.setText(“Select Device”);
tv_toolbar.setTextSize(15);
toolbar.setBackgroundColor(Color.parseColor(“#0079bf”));
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowTitleEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
toolbar.setNavigationOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
}
});
}

//do something you want onBackPressed();
public void launchHomeScreen(){
SharedPreferences pref=this.getSharedPreferences(getResources().getString(R.string.pref_key), 0);
String service_status=pref.getString(“address”,””);
Intent i=new Intent(DeviceListActivity.this, MainActivity.class); i.putExtra(“address”,service_status);
startActivity(i); finish();
}
@Override
public void onResume()
{
super.onResume();
//It is best to check BT status at onResume in case something has changed while app was paused etc checkBTState();
mPairedDevicesArrayAdapter.clear();// clears the array so items aren’t duplicated when resuming from onPause
textConnectionStatus.setText(” “); //makes the textview blank
// Get the local Bluetooth adapter
mBtAdapter=BluetoothAdapter.getDefaultAdapter();
// Get a set of currently paired devices and append to pairedDevices list Set pairedDevices=mBtAdapter.getBondedDevices();
// Add previously paired devices to the array if (pairedDevices.size() > 0){
findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);//make title viewable for (BluetoothDevice device : pairedDevices){
mPairedDevicesArrayAdapter.add(device.getName() + “\n” + device.getAddress());
}
}else{
mPairedDevicesArrayAdapter.add(“no devices paired”);
}
}

//method to check if the device has Bluetooth and if it is on.
//Prompts the user to turn it on if it is off private void checkBTState()
{
// Check device has Bluetooth and that it is turned on
mBtAdapter=BluetoothAdapter.getDefaultAdapter();
// CHECK THIS OUT THAT IT WORKS!!! if(mBtAdapter==null){
Toast.makeText(getBaseContext(), “Device does not support Bluetooth”, Toast.LENGTH_SHORT).show();
finish();
}else{
if (!mBtAdapter.isEnabled()){
//Prompt user to turn on Bluetooth
Intent enableBtIntent=new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
}
}
}
// Set up on-click listener for the listview
private OnItemClickListener mDeviceClickListener=new OnItemClickListener()
{
public void onItemClick(AdapterView av, View v, int arg2, long arg3)
{
textConnectionStatus.setText(“Connecting…”);
// Get the device MAC address, which is the last 17 chars in the View String info=((TextView) v).getText().toString();
String address=info.substring(info.length() – 17); SharedPreferences.Editor editor=pref.edit(); editor.putString(“address”,address);
//Save the address for future reference editor.putBoolean(“isOn”,true);
editor.commit();
BluetoothAdapter btAdapter=BluetoothAdapter.getDefaultAdapter();
BluetoothDevice device=btAdapter.getRemoteDevice(address); boolean enabledBt=false;
//Attempt to create a bluetooth socket for comms try{
BluetoothSocket btSocket=device.createRfcommSocketToServiceRecord(MY_UUID);
if(btSocket.isConnected()){
try{
btSocket.close();
//If IO exception occurs attempt to close socket
}catch (IOException e2){e2.printStackTrace();
}
if(btSocket.isConnected()){
Toast.makeText(getApplicationContext(),”Bluetooth already connected!! If required please restart phone or device bluetooth!!”,Toast.LENGTH_LONG).show();
enabledBt=false; textConnectionStatus.setText(“Connected.”);
}else{try{
btSocket.connect(); try{
btSocket.close();//If IO exception occurs attempt to close socket enabledBt=true;
}catch (IOException e2){e2.printStackTrace();
}
}catch (IOException e){enabledBt=false;
Toast.makeText(getApplicationContext(),”Cannot Connect to device!! Please check if it is On!! Or restart the device”,Toast.LENGTH_LONG).show();
textConnectionStatus.setText(“”);
}
}
}else{try{
btSocket.connect();
btSocket.close();
//If IO exception occurs attempt to close socket enabledBt=true;
}catch (IOException e){e.printStackTrace(); try{
btSocket.close();//If IO exception occurs attempt to close socket btSocket.connect();
btSocket.close();//If IO exception occurs attempt to close socket enabledBt=true;
}catch (IOException e2){enabledBt=false;
Toast.makeText(getApplicationContext(),”Cannot Connect to device!! Please check if it is On!! Or restart the device”,Toast.LENGTH_LONG).show();
e2.printStackTrace(); textConnectionStatus.setText(“”);
}
}
}
}catch (IOException e1){enabledBt=false;
Toast.makeText(getApplicationContext(),”Cannot Connect to device!! Please check if it is On!!
Or restart the device”,Toast.LENGTH_LONG).show(); e1.printStackTrace(); textConnectionStatus.setText(“”);
}
if(enabledBt){
startService(new Intent(DeviceListActivity.this, BluetoothGPSService.class));
}
}
};
@Override
public void onBackPressed(){
AlertDialog.Builder alertBuilder=new AlertDialog.Builder(DeviceListActivity.this);
alertBuilder.setTitle(“Confirm!!”);
alertBuilder.setIcon(android.R.drawable.ic_lock_power_off);
alertBuilder.setMessage(“Are you sure you want to exit?”);
alertBuilder.setPositiveButton(“Yes”, new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){finish();
}
});
alertBuilder.setNegativeButton(“No”, new DialogInterface.OnClickListener(){public void onClick(DialogInterface dialog, int which){
}
});
alertBuilder.setCancelable(false);
AlertDialog dialog=alertBuilder.create();
dialog.getWindow().getAttributes().windowAnimations=R.style.DialogTheme; dialog.show();
}
}
layout_device_list.xml (Design for the listing activity)
<?xml version=”1.0″ encoding=”utf-8″?>
<RelativeLayout xmlns:android=”http://schemas.android.com/apk/res/android” android:orientation=”vertical” android:layout_width=”match_parent” android:layout_height=”match_parent” android:background=”#fff”>
<include android:id=”@+id/tootlbar_head” layout=”@layout/toolbar”/>
<TextView android:id=”@+id/title_paired_devices” android:layout_width=”match_parent” android:layout_height=”wrap_content” android:layout_below=”@+id/tootlbar_head” android:textAppearance=”?android:attr/textAppearanceLarge” android:text=”Select Your Bluetooth GPS from paired devices:” android:visibility=”gone” android:textSize=”15dp” android:textColor=”#0079bf” android:layout_margin=”5dp”/>
<ListView android:id=”@+id/paired_devices” android:layout_width=”match_parent” android:layout_height=”wrap_content” android:layout_below=”@+id/title_paired_devices” android:stackFromBottom=”false” android:layout_weight=”1″/>
<TextView android:id=”@+id/connecting” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:textSize=”20dp” android:layout_below=”@+id/paired_devices” android:textColor=”#0079bf”/>
<TextView android:id=”@+id/infoText” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_margin=”5dp” android:layout_alignParentBottom=”true” android:textStyle=”bold” android:textSize=”15dp” android:text=”If no devices are listed please pair your device in Android settings” android:textColor=”#0079bf” />
<LinearLayout android:layout_width=”match_parent” android:layout_height=”wrap_content” android:gravity=”center”></LinearLayout>
<android.support.design.widget.FloatingActionButton android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:src=”@android:drawable/ic_popup_sync” android:layout_above=”@+id/infoText” android:layout_marginBottom=”5dp” android:id=”@+id/btn_refresh” android:layout_alignParentRight=”true”/>
</RelativeLayout>

Step 3: In the Activity to view the location information add the Broadcast Receiver to get the location data from Bluetooth GPS

In Activity to show/ use location data add the following lines
private BroadcastReceiver mMessageReceiver=new BroadcastReceiver(){@Override
public void onReceive(Context context, Intent intent){
// Get extra data included in the Intent
String message=intent.getStringExtra(“Status”); if(message.equalsIgnoreCase(“true”)){
Bundle b=intent.getBundleExtra(“Location”);
Location lastKnownLoc=(Location) b.getParcelable(“Location”); if (lastKnownLoc !=null){
tvLatitude.setText(String.valueOf(lastKnownLoc.getLatitude()));
tvLongitude.setText(String.valueOf(lastKnownLoc.getLongitude()));
tvAccuracy.setText(String.valueOf(lastKnownLoc.getAccuracy()));
tvTimestamp.setText((new Date(lastKnownLoc.getTime()).toString()));
tvProvider.setText(String.valueOf(lastKnownLoc.getAltitude()));
}
}
tvStatus.setText(message);

// Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
}
};

** Also initialise the Broadcast receiver in onCreate(): LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver, new IntentFilter(“GPSLocationUpdates”));

Step 4: Finally add the service definition in Android Manifest

<service android:name=”.service.BluetoothGPSService”android:enabled=”true”></service>