Develop Reference

Cannot get location from async task

I used async task for upload image in the background thread to show a progress dialog. But while getting a location from async task, it throws the following error:
java.lang.RuntimeException: Can't create handler inside thread that
has not called Looper.prepare()
Although it is work without an async task. I want that process of getting location done in a background thread so that main thread can work without disturbance.
I got error in GPSlocater.java at locationmanager.requestLocationUpdates() while calling from async task.
So what should I do?
This is onLocate function which calls from mainActivity.java
public void onLocate(View view) {
asyncG asyncG1 = new asyncG(this);
asyncG1.execute();
}
This is a sub class which created in mainActivity.java
class asyncG extends AsyncTask
{
Context context;
ProgressDialog progressDialog;
public asyncG(MainActivity mainActivity) {
this.context = mainActivity;
}
#Override
protected Object doInBackground(Object[] objects) {
GPSlocater gpSlocater = new GPSlocater(context);
gpSlocater.getLocation();
lat = gpSlocater.getLatitude();
longi = gpSlocater.getLongitude();
return null;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = new ProgressDialog(context);
progressDialog.setMessage("Finding Location");
progressDialog.show();
}
#Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
progressDialog.dismiss();
Geocoder geocoder = new Geocoder(context, Locale.getDefault());
try {
List<Address> arr;
arr = geocoder.getFromLocation(lat,longi,1);
String pincode = arr.get(0).getPostalCode();
String stat = arr.get(0).getAdminArea();
String city1 = arr.get(0).getLocality();
String city2 = arr.get(0).getSubAdminArea();
String area1 = arr.get(0).getSubLocality();
String area2 = arr.get(0).getLocality();
if(pincode!=null && stat!=null)
{
state.setText(stat);
pin.setText(pincode);
}
if(city1!=null)
{
city.setText(city1);
}
else if(city2!=null)
{
city.setText(city2);
}
if(area1!=null)
{
area.setText(area1);
}
else if(area2!=null)
{
area.setText(area2);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
This is GPSlocater class which called from doInBackground
package com.example.samarth.serviceprovider1;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
public class GPSlocater extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSlocater(Context context) {
this.mContext = context;
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
showSettingsAlert();
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSlocater.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}

you need to create a handler to access UI elements from a thread.
https://developer.android.com/training/multiple-threads/communicate-ui.html
This tutorial should get you going, good luck (:

change coordinate lat and long to andress

how to change the coordinate lat and long that we get and make it to andress.
i'am learning from http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial/.
thank you so much :)
mainactivity.java
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity {
Button btnShowLocation;
// GPSTracker class
GPSTracker gps;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnShowLocation = (Button) findViewById(R.id.btnShowLocation);
// show location button click event
btnShowLocation.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
// create class object
gps = new GPSTracker(MainActivity.this);
// check if GPS enabled
if(gps.canGetLocation()){
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
// \n is for new line
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
}else{
// can't get location
// GPS or Network is not enabled
// Ask user to enable GPS/network in settings
gps.showSettingsAlert();
}
}
});
}
}
GPStracker.java
package unai.skripsi.test;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}

You can simply use this:
Geocoder geocoder;
List<Address> addresses;
geocoder = new Geocoder(this, Locale.getDefault());
addresses = geocoder.getFromLocation(latitude, longitude, 1);
String address = addresses.get(0).getAddressLine(0);
String city = addresses.get(0).getAddressLine(1);
String country = addresses.get(0).getAddressLine(2);

try {
Geocoder geocoder;
final List<Address> addresses;
geocoder = new Geocoder(getApplicationContext(), Locale.getDefault());
if (latitude != 0 || longitude != 0) {
addresses = geocoder.getFromLocation(latitude, longitude, 1);
System.out.println(addresses.get(0).getAddressLine(0)));
}
catch(Exception e){}

class GetLocationName extends AsyncTask<Void, Void, Boolean> {
String result_str;
double latitude;
double longitude;
public GetLocationName(double latitude,double longitude) {
this.latitude=latitude;
this.longitude=longitude;
}
/** hits and returns the location name JsonObject */
public JSONObject getLocationInfo() {
JSONObject jsonObject = new JSONObject();
HttpGet httpGet = new HttpGet(
"http://maps.google.com/maps/api/geocode/json?latlng="
+ latitude + "," + longitude
+ "&sensor=true");
HttpClient client = new DefaultHttpClient();
HttpResponse response;
StringBuilder stringBuilder = new StringBuilder();
try {
response = client.execute(httpGet);
HttpEntity entity = response.getEntity();
InputStream stream = entity.getContent();
int b;
while ((b = stream.read()) != -1) {
stringBuilder.append((char) b);
}
jsonObject = new JSONObject(stringBuilder.toString());
} catch (Exception e) {
e.printStackTrace();
}
return jsonObject;
}
protected Boolean doInBackground(Void... args) {
try {
JSONObject ret = getLocationInfo();
JSONObject location;
String location_string;
location = ret.getJSONArray("results").getJSONObject(0);
location_string = location.getString("formatted_address");
result_str = location_string;
Log.v("Selected", result_str);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
return false;
}
protected void onPostExecute(Boolean result) {
if (result) {
CurrentAddrStr = result_str;//this will have the address
} else {
//something went wrong..
}
super.onPostExecute(result);
}
}
just pass the latitude and longitude to the constructor.

It seems like what you need is the Geocoder. A code example can be found here.

How to get different latitude and longitude while moving for every 1 minute in android?

now i am working with GPS for getting different latitude and longitude for every 1 minute while moving and that has to be stored into array list. I am using thread for this. I followed this link. http://www.androidhive.info/2012/08/android-working-with-google-places-and-maps-tutorial/
And my code is
Tracking.java
package com.example.getlatlang;
import java.util.ArrayList;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class Tracking extends Activity
{
Button btnShowLocation;
boolean isRepeat = true;
protected int splashTime = 1000;
int timer =0;
Thread th;
ArrayList<Double> lat_array = new ArrayList<Double>();
ArrayList<Double> lon_array = new ArrayList<Double>();
// GPSTracker class
GPSTracker gps;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.currentlocation);
btnShowLocation = (Button) findViewById(R.id.start_bt);
// show location button click event
btnShowLocation.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View arg0)
{
// create class object
if(isRepeat)
{
isRepeat = false;
btnShowLocation.setBackgroundResource(R.drawable.stop);
if(lat_array.size()>0 && lon_array.size()>0)
{
lat_array.clear();
lon_array.clear();
System.out.println("Array cleared...");
}
// check if GPS enabled th=new Thread()
th=new Thread()
{
#Override
public void run(){
try
{
for (timer = 0; timer < 20; timer++)
{
// int waited = 0;
// while(waited < splashTime)
// {
Thread.sleep(100);
runOnUiThread(new Runnable()
{
#Override
public void run()
{
try
{ gps = new GPSTracker(Tracking.this);
if(gps.canGetLocation())
{
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
lat_array.add(latitude);
lon_array.add(longitude);
// \n is for new line
System.out.println("lat_array"+lat_array+"lon_array"+lon_array);
Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + lat_array + "\nLong: " + lon_array, Toast.LENGTH_LONG).show();
}
else
{
// can't get location
// GPS or Network is not enabled
// Ask user to enable GPS/network in settings
gps.showSettingsAlert();
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
});
// waited += 100;
//}
}}
catch (InterruptedException e)
{
}
}
};
th.start();
}
else
{
isRepeat = true;
th.interrupt();
btnShowLocation.setBackgroundResource(R.drawable.start);
}
}
});
}
public void ohDestroy()
{
th.stop();
}
}
GPSTracker.java
package com.example.getlatlang;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
public class GPSTracker extends Service implements LocationListener
{
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}
Now my issue is can't able to get different latitude and longitude points while moving. The first value only stored into an array for 20 times. Because i am setting the Tread must be run 20 times like that. But i want to get different points and stored into an array list. I don't know where i did the mistake. Can any body help me to resolve this problem? Thanks in advance.

you have used sleep(100) on the loop of collecting latitude.
The unit of time is micro-second here.(as far as i know)
20*100 = 2000 which is just 2 second. and i don't think GPS update that fast.
Have a look at this.
Rather you can use the same loop but store the value only if it is different from previous one.
if(oldLat != curLat){
//store curLat to array
//and make oldLat = curLat
}

Apply this. It will refresh every 10 seconds.
Handler mHandler1 = new Handler();
new Thread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
while (true) {
try {
Thread.sleep(10000);
mHandler1.post(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
// creating GPS Class object
GPSTracker gps = new GPSTracker (Tracking .this);
// check if GPS location have some values
if (gps.canGetLocation()) {
double currentlat = gps.getLatitude();
double currentlong = gps.getLongitude();
} else {
// no current location
gps.showSettingsAlert();
}
}
});
} catch (Exception e) {
// TODO: handle exception
}
}
}
}).start();

Not receiving Location Updates in Android

I have two classes "GPSTracker" and "Live".
The GPSTracker has the GPS related functions i.e. to get the latitude and the longitude, while the Live class calls it to get the current Latitude and the Longitude and then calculate the distance travelled.
My problem is that I am not getting any changes in the location, the location remains at whatever it is at the start! No locationUpdates!
GPSTracker.java:
public class GPSTracker extends Service implements LocationListener
{
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES =5; // 5 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 5; // 5 seconds
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context)
{
this.mContext = context;
getLocation();
}
public Location getLocation()
{
try
{
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled)
{
// no network provider is enabled
} else
{
this.canGetLocation = true;
if (isNetworkEnabled)
{
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null)
{
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled)
{
if (location == null)
{
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null)
{
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null)
{
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS()
{
if(locationManager != null)
{
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude()
{
if(location != null)
{
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude()
{
if(location != null)
{
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation()
{
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert()
{
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is not enabled");
// Setting Dialog Message
alertDialog.setMessage("Enable location services to determine your location.");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which)
{
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which)
{
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location)
{
}
#Override
public void onProviderDisabled(String provider)
{
}
#Override
public void onProviderEnabled(String provider)
{
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
}
#Override
public IBinder onBind(Intent arg0)
{
return null;
}
}
Live.java:
public class Live extends Activity implements LocationListener
{
GPSTracker gps;
Location newLocation = new Location(LocationManager.GPS_PROVIDER);
Location oldLocation = new Location(LocationManager.GPS_PROVIDER);
float distanceTravelled=0;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_live);
startactivity();
}
public void startactivity()
{
gps = new GPSTracker(Live.this);
if(gps.canGetLocation())
{
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
Toast.makeText(getApplicationContext(), "Your Location is: \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
newLocation.setLatitude(latitude);
newLocation.setLongitude(longitude);
}
else
{
gps.showSettingsAlert();
}
}
public void resumeactivity()
{
gps = new GPSTracker(Live.this);
if(gps.canGetLocation())
{
double latitude = gps.getLatitude();
double longitude = gps.getLongitude();
//Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
newLocation.setLatitude(latitude);
newLocation.setLongitude(longitude);
}
else
{
}
}
public void onResume()
{
super.onResume();
resumeactivity();
}
#Override
public void onLocationChanged(Location location)
{
oldLocation.set(newLocation);
newLocation.set(location);
//resumeactivity();
distanceTravelled+=newLocation.distanceTo(oldLocation);
String stringDistance= Float.toString(distanceTravelled);
TextView distance = (TextView) findViewById(R.id.textDistance);
distance.setText(stringDistance);
}
#Override
public void onProviderDisabled(String arg0)
{
GPSTracker gps = new GPSTracker(Live.this);
gps.showSettingsAlert();
}
#Override
public void onProviderEnabled(String arg0)
{
}
#Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2)
{
}

I was facing same problem with my app, so what I did is reboot phone and Start the app under clear sky. It will might help you.

You can find a working example here. It is not calculating the distance, but this should be easy to add.

java class to call back activity when location updates

I found this class I'd like to use to obtain location updates but I'm trying to find out how to implement callbacks to the activity when location updates.
Do I use some callback or other type of method to implement this?
note I got the code from http://www.androidhive.info/2012/07/android-gps-location-manager-tutorial/
GPSTracker.java
package com.example.gpstracking;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute
// Declaring a Location Manager
protected LocationManager locationManager;
public GPSTracker(Context context) {
this.mContext = context;
getLocation();
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// First get location from Network Provider
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
* */
public void stopUsingGPS(){
if(locationManager != null){
locationManager.removeUpdates(GPSTracker.this);
}
}
/**
* Function to get latitude
* */
public double getLatitude(){
if(location != null){
latitude = location.getLatitude();
}
// return latitude
return latitude;
}
/**
* Function to get longitude
* */
public double getLongitude(){
if(location != null){
longitude = location.getLongitude();
}
// return longitude
return longitude;
}
/**
* Function to check GPS/wifi enabled
* #return boolean
* */
public boolean canGetLocation() {
return this.canGetLocation;
}
/**
* Function to show settings alert dialog
* On pressing Settings button will lauch Settings Options
* */
public void showSettingsAlert(){
AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);
// Setting Dialog Title
alertDialog.setTitle("GPS is settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");
// On pressing Settings button
alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int which) {
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
mContext.startActivity(intent);
}
});
// on pressing cancel button
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Showing Alert Message
alertDialog.show();
}
#Override
public void onLocationChanged(Location location) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}

Yeah you should add a callback method like that :
public GPSTracker(Context context, Activity calleractivity) {
this.mContext = context;
getLocation();
this.calleractivity=calleractivity
}
And your update method would be something like
public void update(){
calleractivity.getback();
}
And in your activity :
gps = new GPSTracker(Context context, this);
I hope it helps

Some notes:
Services run on the UI thread by default. This class might block your UI if getting location from a particular source takes a long time. How often do you need updates? You could run a timer to send out requests to an IntentService to get GPS info.
If you really do need GPS "tracking", then you're doing the right thing, but remember that GPS drains the battery quickly.
The best way to communicate from one Android component to another is to use a BroadcastReceiver. This provides a clear, straightforward callback that can handle more than one "message" from various components.

This code can be used to get location using your GPSTracker class, Paste your code on your activity onCreate method for testing purpose. Yes it will block your UI thread for now but you will get the location. After that you can read about using Service in Android to get a better idea.
LocationResult locationResult = new LocationResult() {
#Override
public void gotLocation(Location location) {
Log.d("Activity","In gotLocation Listener");
boolean hasAddedQr = false;
if(hasAddedQr){
return;
}
hasAddedQr = true;
if (location != null) {
Log.d("Activity","Got the location");
// Got the location!
try {
double lati = location.getLatitude();
double longi = location.getLongitude();
text.setText("Got Location: La="+lati+", Lo="+longi);
} catch (Exception e) {
// TODO: handle exception
}
} else {
GetLocation.this.runOnUiThread(new Runnable() {
#Override
public void run() {
// TODO Auto-generated method stub
text.setText("Location was returned null");
}
});
}
}
};
GPSTracker myLocation = new GPSTracker();
boolean isEnabled = myLocation.getLocation(GetLocation.this, locationResult);
if(!isEnabled){
Log.d("Activity", "LOCATION SERVICES WERE NOT ENABLED");
text.setText("Location service not available");
getLocationBtn.setEnabled(true);
}
else{
Log.d("Activity", "LOCATION SERVICES ENABLED");
}