android null pointer exceptions in AsyncTask [closed] - android

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Closed 9 years ago.
I'm just starting to write under the android and ran into the problem that I do not know how to solve
PostData.java
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.app.Activity;
import android.os.AsyncTask;
import android.text.format.Time;
import android.util.Log;
import android.widget.EditText;
import android.widget.Toast;
class PostData extends AsyncTask<Void, Void, Void> {
// GPSTracker class
GPSTracker gps;
//определяем переменную главного активити
MainActivity ma;
Teleport_user_profile_activity UP;
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
// do stuff before posting data
super.onPreExecute();
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
postData();
return null;
}
#Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
// do stuff after posting data
super.onPostExecute(result);
}
public void postData() {
// TODO Auto-generated method stub
// Create a new HttpClient and Post Header
//переводим значение double в стринг
double latitudep = gps.getLatitude();
double longitudep = gps.getLongitude();
double totalLatitude = latitudep;
String stotalLatitude = String.valueOf(totalLatitude);
double totalLongitude = longitudep;
String stotalLongitude = String.valueOf(totalLongitude);
// временная переменная для определения времени устройства
Time nowTime = new Time();
nowTime.setToNow();
String snowTime = String.valueOf(nowTime);
//берем информацию о юзере
UP.LoadUserInfoFromFile();
UP.LoadUserInfopassFromFile();
String UserInfo = Teleport_user_profile_activity.UserLoginFile;
String UserPass = Teleport_user_profile_activity.UserPassFile;
//посылка данных на сервер
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://myheart.pp.ua/Android_in.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(4);
// nameValuePairs.add(new BasicNameValuePair("latitude", stotalLatitude));
// nameValuePairs.add(new BasicNameValuePair("longitude", stotalLongitude));
nameValuePairs.add(new BasicNameValuePair("Android_device_time", snowTime));
// nameValuePairs.add(new BasicNameValuePair("user_info", UserInfo));
// nameValuePairs.add(new BasicNameValuePair("user_pass", UserPass));
nameValuePairs.add(new BasicNameValuePair("separator", "______________________________________"));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpclient.execute(httppost);
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
} catch (NullPointerException e) {
e.printStackTrace();
}
}
}
MainActivity.java
R.id.menu_send_location_manual: {
GPSdetermination();
new PostData().execute();
// postData(); - вызывает ошибку на реальном устройстве
Toast.makeText(getApplicationContext(), R.string.location_send_manuall_toast, Toast.LENGTH_LONG).show();
break;
}
public void GPSdetermination() {
// 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
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
//определяем переменную главного активити
MainActivity ma;
// 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();
}
// Функция для определения местоположения
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();
}
//события которые происходят если позиция поменялась
#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;
}
When I try to call PostData I get an error java.lang.NullPointerException in this code
double latitudep = gps.getLatitude();
double longitudep = gps.getLongitude();
can not seem to figure out how to fix it.

You have declared GPSTracker gps; inside your AsyncTask, it never seems to get initialised. In other words, it's null. Thus, NullPointerException.
I guess you need a constructor for your AsyncTask to set it:
public PostData (GPSTracker gps) {
this.gps = gps;
}
Then in MainActivity
new PostData(gps).execute();
AsyncTask is just a class like any other, with member variables, that need setting, if you want to use them.

gps is null because it isn't instantiated. In doInBackground() you can instantiate it
gps = new GPSTracker();
But since your GPSTracker constructor needs a Context you will have to add a constructor to your AsyncTas that accepts a Context
Async
pubic class PostData extends AsyncTask<Void, Void, Void> {
Context mContext;
MainActivity ma;
Teleport_user_profile_activity UP;
public PostData(Context c)
{
mContext = c;
}
Then in doInBackground()
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
gps = new GPSTracker(mContext);
postData();
return null;
}
And call your AsyncTask like this in MainActivity
R.id.menu_send_location_manual: {
GPSdetermination();
PostData task = new PostData(MainActivity.this);
task.execute();
new PostData().execute();

Your problem is that GPS can only be listened to within a regular thread, like the UI thread and not the doInBackground() method of an AsyncTask. This has to do with the fact that it requires a Looper to function properly. Here's a good post that's very similar to your problem.
Get your GPS data first in onCreate then you can transfer that data to your AsyncTask as varargs and use it in doInBackground that way.

Related

How to get current coordinates/location in android

I've been working on trying to get the current location in android since several days but I didn't find a solution yet.
I know there are similar topics regarding this but in my case the code it didn't work. Is there anyone who has already solved this issue and can help me?
I add some tests I did.
Here's the GPS Tracker class.
package utility;
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 = 1; // 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) {
try {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
} catch (SecurityException e) {
}
Log.d("Network", "Network");
if (locationManager != null) {
try {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
} catch (SecurityException e) {
}
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
}
}
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
try {
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 (SecurityException s) {
}
}
}
}
} 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) {
try {
locationManager.removeUpdates(GPSTracker.this);
} catch (SecurityException e) {
}
}
}
/**
* 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 Settings");
// Setting Dialog Message
alertDialog.setMessage("GPS is not active. Do you want to open?");
// 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;
}
}
And I instantiated this class in my activity, as follows:
import android.os.Bundle;
import android.app.Activity;
import android.widget.ImageButton;
import android.widget.TextView;
import utility.GPSTracker;
public class AroundMeActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_around_me);
TextView location_text = (TextView) findViewById(R.id.location_text);
GPSTracker gps;
double latitude = 0.0;
double longitude = 0.0;
gps = new GPSTracker(AroundMeActivity.this);
// check if GPS enabled
if(gps.canGetLocation())
{
latitude = gps.getLatitude();
longitude = gps.getLongitude();
}
else
{
gps.showSettingsAlert();
}
location_text.setText(latitude + " " + longitude);
}
}
The results is 0.0 for both latitude and longitude.
Thank you in advance guys!!!
Use android LocationMannager
Checkout androidhive tutorial about Android GPS, Location Manager to get started
Here is a great library, very easy to use and lightweight: https://github.com/mrmans0n/smart-location-lib
Just compile it with gradle and thats' it.

Longitude and Latitude showing 0.0 in Service

I want to make a notification that contain longitude and latitude in every 5 minutes. And I make 2 service, but I the longitude and latitude can not be displayed in my apps.
this is my GPS Service
package com.example.michael.eksperimen4gpstrack;
/**
* Created by Michael on 01/12/2015.
*/
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;
import java.util.Timer;
public class GPSTracker extends Service implements LocationListener {
private final Context mContext;
private static final long NOTIFY_INTERVAL = 10 * 1000; // 10 detik
private Timer mTimer = null;
// 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;
}
}
And this is my timer service
package com.example.michael.eksperimen4gpstrack;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import java.util.logging.Handler;
/**
* Created by Michael on 14/12/2015.
*/
public class LocService extends Service
{
public static final long NOTIFY_INTERVAL = 5*1000; // 10 detik
private android.os.Handler mHandler = new android.os.Handler();
public Timer mTimer = null;
GPSTracker gps;
public IBinder onBind(Intent arg0)
{
return null;
}
public void onCreate()
{
if(mTimer != null)
{
mTimer.cancel();
}
else
{
mTimer = new Timer();
}
mTimer.scheduleAtFixedRate(new TimeDisplayTimerTask(), 0, NOTIFY_INTERVAL);
}
class TimeDisplayTimerTask extends TimerTask
{
#Override
public void run()
{
gps = new GPSTracker(getApplicationContext());
mHandler.post(new Runnable()
{
#Override
public void run()
{
// 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 + "\n\n"+getDateTime(), 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();
}
}
});
}
}
public int onStartCommand(Intent intent, int flags, int startId)
{
Toast.makeText(this, "Service Started", Toast.LENGTH_SHORT).show();
return START_STICKY;
}
public void onDestroy()
{
super.onDestroy();
Toast.makeText(this, "Service Destroyed", Toast.LENGTH_SHORT).show();
}
private String getDateTime()
{
// get date time in custom format
SimpleDateFormat sdf = new SimpleDateFormat("[yyyy/MM/dd - HH:mm:ss]");
return sdf.format(new Date());
}
}
When toast displayed, the longitude and latitude still 0.0, anyone can help me please?
Gratia
Replace your TimeDisplayTimerTask with following code:
Initialize gps within run method.
class TimeDisplayTimerTask extends TimerTask
{
#Override
public void run()
{
mHandler.post(new Runnable()
{
#Override
public void run()
{
gps = new GPSTracker(getApplicationContext());
// 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 + "\n\n"+getDateTime(), 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();
}
}
});
}
}
Wait sometime because getting gps-coordinates from gps takes some time.

how to run locationlistener in background

I would like to run a locationlistener on my app, that send after every 10m or every 5 seconds an new "Popup". Later I will send my data to the cloud.
This is my GPSTracker class:
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;
import android.widget.Toast;
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 * 5 * 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) {
Toast.makeText(GPSTracker.this,"Provider enabled by the user. GPS turned on",Toast.LENGTH_LONG).show();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public IBinder onBind(Intent arg0) {
return null;
}
}
For my activityclass I have made this:
gps = new GPSTracker(MainActivity.this);
double latitude2 = gps.getLatitude();
double longitude2 = gps.getLongitude();
I receive the data, this works. But now I want to run the data in the background so when the location is changed I can implement a function that sends my data to the cloud.
I tried this:
private void startGPSTrackerInBackground() {
new AsyncTask<Void,Void,String>() {
#Override
protected String doInBackground(Void... params) {
String msg = "This message runs in background";
gps = new GPSTracker(MainActivity.this);
if(!gps.canGetLocation()){
gps.showSettingsAlert();
}else{
gps = new GPSTracker(MainActivity.this);
double latitude2 = gps.getLatitude();
double longitude2 = gps.getLongitude();
}
return msg;
}
#Override
protected void onPostExecute(String msg) {
mDisplay.append(msg + "\n");
}
}.execute(null, null, null);
}
But in this function it's not possible to get the information of my GPSTracker class, anyone an idea to make this possible?
Create an independent class, add a GPSTracker member variable and pass it in the constructor. Wrap your task in a method you can invoke later:
public class BackgroundGPSTracker() {
GPSTracker tracker;
public BackgroundGPSTracker(GPSTracker tracker) {
this.tracker = tracker;
}
public void run() {
new AsyncTask<Void,Void,String>() {
#Override
protected String doInBackground(Void... params) {
// Do some background stuff.
}
#Override
protected void onPostExecute(String msg) {
// Do after work stuff
}
}.execute(null, null, null);
}
}
Use:
If you create GPSTracker like this:
gps = new GPSTracker(MainActivity.this);
Then you start the activity passing it to the task:
BackgroundGPSTracker bgGPSTracker= new BackgroundGPSTracker(gps);
bgGPSTracker.run();
EDIT
Use a member variable to store last known location, and timer to schedule updates:
public class CampaignsDiscoverActivity extends Activity{
static final int QUERY_CAMPAINGS_DELAY = 30000;// milliseconds
Location currentLocation;
Timer timer;
void restartTimer() {
timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
sendDataToServerOrWhatever();
}
}, QUERY_CAMPAINGS_DELAY, QUERY_CAMPAINGS_DELAY);
}
void stopTimer() {
if (timer != null) {
timer.cancel();
timer = null;
}
}
void sendDataToServerOrWhatever() {
// Do some stuff using currentLocation
}
Set a listener for locations changes. when location changed is raised, stop the timer, do work and restart it:
void startGPSUpdates() {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationListener = new LocationListener() {
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
#Override
public void onLocationChanged(Location location) {
stopTimer();
currentLocation = location;
sendDataToServerOrWhatever();
}
};
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
// Initialize location.
currentLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (currentLocation == null) {
currentLocation = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
}
restartTimer();
}
To start the system just invoke startGPSUpdates.
You should pause listeners when app goes to the background and resume when foreground:
#Override
public void onPause() {
super.onPause();
if (applicationData.isLoggedIn()) {
pauseLocationUpdates();
}
}
#Override
public void onResume() {
super.onResume();
if (applicationData.isLoggedIn()) {
resumeLocationUpdates();
}
}
void pauseLocationUpdates() {
locationManager.removeUpdates(locationListener);
}
void resumeLocationUpdates() {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
I think you should do the same with the timer, but the app where I'm using it is not finished and fully tested yet, so you might find bugs.
Hope that helps.

Not getting Latitude and longitude after every 1 minute in android

I want to make an android program in that I get latitude and longitude in Toast after each 1 minute interval and populated on toast even after my application closed.
I have tried as below,But I only getting on time latitude and longitude,Please tell me what should i do for it to get continuously lat long in toast.My code is as below:
GPStracker.java
package com.epe.trucktrackers;
import java.util.Timer;
import java.util.TimerTask;
import utils.Const;
import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
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;
import android.widget.Toast;
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;
private Timer timer;
private long UPDATE_INTERVAL;
public static final String Stub = null;
LocationManager mlocmag;
LocationListener mlocList;
private double lat, longn;
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; // 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) {
String message = String.format(
"Location \n Longitude: %1$s \n Latitude: %2$s",
location.getLongitude(), location.getLatitude());
System.out.println(":::::::::::Ne lat longs............!!!" + message);
longitude = location.getLongitude();
latitude = location.getLatitude();
Toast.makeText(mContext, latitude + " " + longitude, Toast.LENGTH_LONG)
.show();
/* UpdateWithNewLocation(location); */
System.out.println(":Location chane");
}
#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;
}
}
Activity.java
package com.epe.trucktrackers;
import org.json.JSONException;
import org.json.JSONObject;
import utils.Const;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import backend.BackendAPIService;
public class MainActivity extends Activity {
EditText et_registration_no;
Button btn_register;
static GPSTracker gps;;
String lat, lng;
private ProgressDialog pDialog;
String udid;
String status;
String tracking_id;
String UDID;
String lati;
String longi;
String registration_no;
int flag;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et_registration_no = (EditText) findViewById(R.id.et_truck_no);
btn_register = (Button) findViewById(R.id.btn_reg);
TelephonyManager TelephonyMgr = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
udid = TelephonyMgr.getDeviceId();
gps = new GPSTracker(MainActivity.this);
btn_register.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
gps = new GPSTracker(MainActivity.this);
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();
lat = latitude + "";
lng = longitude + "";
} else {
// can't get location
// GPS or Network is not enabled
// Ask user to enable GPS/network in settings
gps.showSettingsAlert();
}
new RegistartionApi().execute();
System.out
.println("::::::::::::::service started:::::::::::::");
}
});
// api call for the REGISTARTION ..!!
}
class RegistartionApi extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
System.out
.println("==========inside preexecute===================");
}
#Override
protected Void doInBackground(Void... arg0) {
String registrationURL = Const.API_REGISTRATION + "?UDID=" + udid
+ "&latitude=" + lat + "&longitude=" + lng
+ "&registration_no="
+ et_registration_no.getText().toString().trim();
registrationURL = registrationURL.replace(" ", "%");
BackendAPIService sh = new BackendAPIService();
System.out.println(":::::::::::::Registration url:::::::::::;"
+ registrationURL);
String jsonStr = sh.makeServiceCall(registrationURL,
BackendAPIService.POST);
Log.d("Response: ", "> " + jsonStr);
System.out.println("=============MY RESPONSE==========" + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
JSONObject c = new JSONObject(jsonStr);
if (jsonObj.has("status")) {
status = jsonObj.getString("status");
{
if (status.equalsIgnoreCase("success")) {
flag = 1;
c = jsonObj.getJSONObject("truck_tracking");
tracking_id = c.getString("tracking_id");
UDID = c.getString("UDID");
lati = c.getString("latitude");
longi = c.getString("longitude");
registration_no = c
.getString("registration_no");
} else {
flag = 2;
Toast.makeText(MainActivity.this, "Failed",
Toast.LENGTH_SHORT).show();
}
}
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
if (flag == 1) {
Toast.makeText(MainActivity.this, "Registration Done",
Toast.LENGTH_SHORT).show();
/*Intent i = new Intent(getApplicationContext(), GPSTracker.class);
startService(i);*/
}
}
}
}
Try this one.
package com.sample.location;
import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
public class MyLocation {
Timer timer1;
LocationManager lm;
LocationResult locationResult;
boolean gps_enabled = false;
boolean network_enabled = false;
public boolean getLocation(Context context, LocationResult result) {
// I use LocationResult callback class to pass location value from
// MyLocation to user code.
locationResult = result;
if (lm == null)
lm = (LocationManager) context
.getSystemService(Context.LOCATION_SERVICE);
// exceptions will be thrown if provider is not permitted.
try {
gps_enabled = lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
} catch (Exception ex) {
}
try {
network_enabled = lm
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
} catch (Exception ex) {
}
// don't start listeners if no provider is enabled
if (!gps_enabled && !network_enabled)
return false;
if (gps_enabled)
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0,
locationListenerGps);
if (network_enabled)
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0,
locationListenerNetwork);
timer1 = new Timer();
timer1.schedule(new GetLastLocation(), 60*1000);
return true;
}
LocationListener locationListenerGps = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
timer1.cancel();
locationResult.gotLocation(location);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerNetwork);
}
/**
* Called when the provider is disabled by the user. If requestLocationUpdates is called on an already disabled provider, this method is called immediately.
* #param provider
* the name of the location provider associated with this update.
*/
#Override
public void onProviderDisabled(String provider) {
}
/**
* Called when the provider is enabled by the user.
* #param provider
* the name of the location provider associated with this update.
*/
#Override
public void onProviderEnabled(String provider) {
}
/**
* Called when the provider status changes. This method is called when a provider is unable to fetch a location or if the provider has recently become available after a period of unavailability.
* #param provider
* the name of the location provider associated with this update.
* #param status
* OUT_OF_SERVICE if the provider is out of service, and this is not expected to change in the near future; TEMPORARILY_UNAVAILABLE if the provider is temporarily unavailable but is expected to be available shortly; and AVAILABLE if the provider is currently available.
* #param extras
* an optional Bundle which will contain provider specific status variables.
A number of common key/value pairs for the extras Bundle are listed below. Providers that use any of the keys on this list must provide the corresponding value as described below.
satellites - the number of satellites used to derive the fix
*/
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
};
LocationListener locationListenerNetwork = new LocationListener() {
/**
* Called when the location has changed.
* There are no restrictions on the use of the supplied Location object.
* #param location
* The new location, as a Location object.
*/
#Override
public void onLocationChanged(Location location) {
timer1.cancel();
locationResult.gotLocation(location);
lm.removeUpdates(this);
lm.removeUpdates(locationListenerGps);
}
/**
* Called when the provider is disabled by the user. If requestLocationUpdates is called on an already disabled provider, this method is called immediately.
* #param provider
* the name of the location provider associated with this update.
*/
#Override
public void onProviderDisabled(String provider) {
}
/**
* Called when the provider is enabled by the user.
* #param provider
* the name of the location provider associated with this update.
*/
#Override
public void onProviderEnabled(String provider) {
}
/**
* Called when the provider status changes. This method is called when a provider is unable to fetch a location or if the provider has recently become available after a period of unavailability.
* #param provider
* the name of the location provider associated with this update.
* #param status
* OUT_OF_SERVICE if the provider is out of service, and this is not expected to change in the near future; TEMPORARILY_UNAVAILABLE if the provider is temporarily unavailable but is expected to be available shortly; and AVAILABLE if the provider is currently available.
* #param extras
* an optional Bundle which will contain provider specific status variables.
A number of common key/value pairs for the extras Bundle are listed below. Providers that use any of the keys on this list must provide the corresponding value as described below.
satellites - the number of satellites used to derive the fix
*/
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
};
/**
* The GPS location and Network location to be calculated
* in every 5 seconds with the help of this class
*
*/
class GetLastLocation extends TimerTask {
#Override
public void run() {
lm.removeUpdates(locationListenerGps);
lm.removeUpdates(locationListenerNetwork);
Location net_loc = null, gps_loc = null;
if (gps_enabled)
gps_loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (network_enabled)
net_loc = lm
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
// if there are both values use the latest one
if (gps_loc != null && net_loc != null) {
if (gps_loc.getTime() > net_loc.getTime())
locationResult.gotLocation(gps_loc);
else
locationResult.gotLocation(net_loc);
return;
}
if (gps_loc != null) {
locationResult.gotLocation(gps_loc);
return;
}
if (net_loc != null) {
locationResult.gotLocation(net_loc);
return;
}
locationResult.gotLocation(null);
}
}
/**
* This abstract class is used to get the location from other class.
*
*/
public static abstract class LocationResult {
public abstract void gotLocation(Location location);
}
}
In your Activity.java
LocationManager myLocationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
MyLocation myLocation = new MyLocation();
myLocation.getLocation(getApplicationContext(), locationResult);
LocationResult locationResult = new LocationResult() {
#Override
public void gotLocation(Location location) {
double latitude = location.getLatitude();
double longitude = location.getLongitude();
}
};

show complete address instead of longitude and latitude

I am working on GPS location whereby i get the longitude and latitude but i dont know how to get the complete address instead of this. i have followed a tutorial for my code and saw many posts to find out how can i get the address based on this but coudnt find any probable solution
Following is my code:
GpsTracker.java
package com.example.gpslocator;
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;
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;
}
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 arg0) {
// TODO Auto-generated method stub
}
#Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
#Override
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
#Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
#Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
}
MainActivity.java
package com.example.gpslocator;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
Button btnShowLocation;
TextView textview;
// GPSTracker class
GpsTracker gps;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
GpsTracker gpsTracker = new GpsTracker(this);
btnShowLocation = (Button) findViewById(R.id.button1);
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();
}
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Use the received location and feed it to the GeoCoder or the Geocoding API.
The GeoCoder is part of the SDK since API Level 1 and results in an ArrayList of Address Objects.
Geocoding is a web-service, which responses a JSON.
Both solutions are delivering detailed information and can be used for geocoding (location to address) or reverse geocoding (address to location).
Edit:
Use the GeoCoder like this:
if(GeoCoder.isPresent()) {
Geocoder geocoder = new Geocoder(this);
List<Address> addresses = null;
try {
addresses = geocoder.getFromLocationName(latitude, longitude, 1);
if (!addresses.isEmpty()) {
Address address = list.get(0);
// do something with your address
} else {
// No results for your location
}
} catch (IOException e) {
e.printStackTrace();
}
}

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