Develop Reference

In Android Studio, I am not able to move google map and it always returns to current location

My problem is: When I'm trying to move around in the map or zoom in & out it immediately return to my current location. Also when I search for location, new marker added at the searched location but immediately goes back to my current location.
I searched for solution but found nothing.. I hope somebody can figure it out
package com.hitman.locationrevision;
import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.FragmentActivity;
import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.location.LocationRequest;
import android.os.Bundle;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.hitman.locationrevision.databinding.ActivityMapsBinding;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
LocationManager locationManager;
LocationListener locationListener;
>function for current location information
public void locationInfo(Location location,String title){
if(location != null) {
LatLng currentLocation = new LatLng(location.getLatitude(), location.getLongitude());
mMap.clear();
mMap.addMarker(new MarkerOptions().position(currentLocation).title(title));
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation,10));
}
}
>function to request permission from user
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if(grantResults.length>0 && grantResults[0]==PackageManager.PERMISSION_GRANTED){
if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION)==PackageManager.PERMISSION_GRANTED){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
Location lastLocation=locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
locationInfo(lastLocation,"Your lastLocation");
}
}
}
private GoogleMap mMap;
private ActivityMapsBinding binding;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMapsBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
Intent intent=getIntent();
locationManager=(LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationListener=new LocationListener() {
#Override
public void onLocationChanged(#NonNull Location location) {
locationInfo(location,"Your Location");
}
};
>code to ask permission and check permission from user
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)!= PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},1);
}else{
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
>code to find the last location and update the last location
Location
lastLocation=locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
locationInfo(lastLocation,"Your lastlocation");
}
}
}

Its because you have move camera when your location update. You just need to put condition whether its user call or not to see current location.
Here is the line, this will alway move camera and display your current location
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation,10));
You can do like this, whenever user required to see current location then change fromUser = true and then make to false back. Just like happen in Google Map when you click on location button.
var fromUser = false;
if(fromUser){
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation,10));
fromUser = false;
}

Use this code for get current location.this method only get one time
of user location.inside OnLocationResult callback handle your location
logic
private void getCurrentLocation(){
LocationRequest locationRequest = new LocationRequest();
FusedLocationProviderClient fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setMaxWaitTime(1000);
locationRequest.setFastestInterval(500);
locationRequest.setInterval(500);
fusedLocationProviderClient.requestLocationUpdates(locationRequest, new LocationCallback() {
#Override
public void onLocationResult( LocationResult locationResult) {
if(locationResult.getLocations().size() != 0){
Location location = locationResult.getLocations().get(0);
LatLng latLng = new LatLng(location.getLatitude(),location.getLongitude());
//handle current user location logic
FusedLocationProviderClient.removeLocationUpdates(this);
}
}
}, Looper.getMainLooper());
}

Android Java Google API app crashing when allowing location access, but no problem when deny location...? [duplicate]

This question already has answers here:
Android LocationListener, AbstractMethodError on onStatusChanged and onProviderDisabled
(6 answers)
Closed 1 year ago.
I've tried this code from an UDEMY Course. Written same like him, he can access to location & also got a Toast while I cant opening app with allowed Location.
When allowing location, my app crashing.
But when deny I can see the map and not crashing anymore.
***My google map API also working good. also taken user Internet & Location Service.
MapsActivity.java:
package com.project.demo2map;
import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.FragmentActivity;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.project.demo2map.databinding.ActivityMapsBinding;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
private ActivityMapsBinding binding;
LocationManager locationManager;
LocationListener locationListener;
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0, locationListener);
}
}
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMapsBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationListener = new LocationListener() {
#Override
public void onLocationChanged(#NonNull Location location) {
Toast.makeText(MapsActivity.this, location.toString(), Toast.LENGTH_SHORT).show();
}
};
if (Build.VERSION.SDK_INT < 23) {
locationManager.requestLocationUpdates(LocationManager.
GPS_PROVIDER, 0, 0, locationListener);
}else {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
} else {
locationManager.requestLocationUpdates(LocationManager.
GPS_PROVIDER, 0, 0, locationListener);
}
}
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}
CrashLog:
2021-10-25 14:59:29.003 25984-25984/com.project.demo2map D/AndroidRuntime: Shutting down VM
2021-10-25 14:59:29.006 25984-25984/com.project.demo2map E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.project.demo2map, PID: 25984
java.lang.AbstractMethodError: abstract method "void android.location.LocationListener.onProviderDisabled(java.lang.String)"
at android.location.LocationManager$ListenerTransport._handleMessage(LocationManager.java:365)
at android.location.LocationManager$ListenerTransport.access$000(LocationManager.java:275)
at android.location.LocationManager$ListenerTransport$1.handleMessage(LocationManager.java:291)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:491)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:925)

Overriding the onProviderChanged() method will fix this problem.

check if any providers active.
if( locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER) ||
locationManager .isProviderEnabled(LocationManager.GPS_PROVIDER)){
//start listener to requestUpdates ...
}else{
//show message, no providers enabled.
}

Error inflating class fragment occurs when marking location (lat and longitude from sql) onto the google map

I encountered error inflating class fragment when I tried to mark the location (lat and longitude from SQL) onto the google map for the android java app. In MapsActivity.java, it is already using onCreate, not onCreateView. Do I have to change it or is there any way I can solve the error?
MapsActivity.java
package com.example.paddy_disease_tracker;
import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.widget.Toast;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.fragment.app.FragmentActivity;
import com.example.paddy_disease_tracker.databinding.ActivityMapsBinding;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
String query;
Statement st;
ResultSet rs;
Toast toast;
String disease;
float lat,lon;
private GoogleMap mMap;
private ActivityMapsBinding binding;
LatLng centerLocation,place;
Connection connect;
ArrayList<LatLng> places=new ArrayList<LatLng>();
ArrayList<String> dis=new ArrayList<String>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMapsBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
centerLocation=new LatLng(6.0,101);
try {
ConnectionHelper connectionHelper = new ConnectionHelper();
connect = connectionHelper.connectionclass();
if (connect != null) {
query = "Select * from Disease";
st = connect.createStatement();
rs = st.executeQuery(query);
while (rs.next()) {
disease=rs.getString(3);
lat=rs.getFloat(4);
lon=rs.getFloat(5);
places.add(new LatLng(lat,lon));
dis.add(disease);
}
} else {
toast=Toast.makeText(getApplicationContext(),"Check Connection",Toast.LENGTH_LONG);
toast.show();
}
}catch(Exception e){
toast=Toast.makeText(getApplicationContext(),e.getMessage(),Toast.LENGTH_LONG);
toast.show();
}
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
enableMyLocation();
// Add a marker in Sydney and move the camera
for(int i=0; i<places.size();i++){
mMap.addMarker(new MarkerOptions().position(places.get(i)).title(dis.get(i)+" found"));
}
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(centerLocation,6));
}
private void enableMyLocation() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
if (mMap != null) {
mMap.setMyLocationEnabled(true);
}
} else {
String []perms={"android.permission.ACCESS_FINE_LOCATION"};
// Permission to access the location is missing. Show rationale and request permission
ActivityCompat.requestPermissions(this,perms,200);
}
}
}

Geocoding in android app

I am not able to figure out why i am getting null pointer exception everytime i am running the app.This android app finds the place and marks it on the map using geocoding.But i have not succeded in doing so and not getting to know where is the mistake.Please help!
The main activity code is as follows:
package com.dutt.rishabh.locator;
import android.location.Address;
import android.location.Geocoder;
import android.os.AsyncTask;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import java.io.IOException;
import java.util.List;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
EditText x;
Button bfind;
String location;
MarkerOptions markerOptions;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
bfind=(Button)findViewById(R.id.bfind);
View.OnClickListener findClickListener =new View.OnClickListener() {
#Override
public void onClick(View view) {
x=(EditText)findViewById(R.id.etsearch);
location=x.getText().toString();
if(location!=null || location.equals("")){
new GeocoderTask().execute(location);
}
}
};
bfind.setOnClickListener(findClickListener);
}
private class GeocoderTask extends AsyncTask<String, Void, List<Address>>{
#Override
protected List<Address> doInBackground(String... strings) {
Geocoder geocoder = new Geocoder(getBaseContext());
List<Address> addresses=null;
try {
addresses=geocoder.getFromLocationName(strings[0],3);
} catch (IOException e) {
e.printStackTrace();
}
return addresses;
}
#Override
protected void onPostExecute(List<Address> addresses){
if(addresses==null || addresses.size()==0){
Toast.makeText(getBaseContext(),"No location found",Toast.LENGTH_SHORT).show();
}
mMap.clear();
for(int i=0;i<addresses.size();i++){
Address address= addresses.get(i);
LatLng latLng=new LatLng(address.getLatitude(),address.getLongitude());
String addressText=String.format("%s,%s",address.getMaxAddressLineIndex()>0?address.getAddressLine(0):"",address.getCountryName());
markerOptions=new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title(addressText);
mMap.addMarker(markerOptions);
if(i==0){
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
}
}
}
}
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to install
* it inside the SupportMapFragment. This method will only be triggered once the user has
* installed Google Play services and returned to the app.
*/
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
}
Please help and kindly mention my mistake so i can understand.
The following is the logcat :
07-26 15:02:02.264 30388-30388/com.dutt.rishabh.locator E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.dutt.rishabh.locator, PID: 30388
java.lang.NullPointerException
at com.dutt.rishabh.locator.MapsActivity$GeocoderTask.onPostExecute(MapsActivity.java:75)
at com.dutt.rishabh.locator.MapsActivity$GeocoderTask.onPostExecute(MapsActivity.java:57)
at android.os.AsyncTask.finish(AsyncTask.java:632)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5345)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:828)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:644)
at dalvik.system.NativeStart.main(Native Method)

Null check for addresses
for(int i=0;i<addresses.size();i++){
}
or add return
if(addresses==null || addresses.size()==0){
Toast.makeText(getBaseContext(),"No location found",Toast.LENGTH_SHORT).show();
return;
}

In your case the address list seems to be null. You can return code execution after showing the toast message.
if(addresses==null || addresses.size()==0){ // Line 71
Toast.makeText(getBaseContext(),"No location found",Toast.LENGTH_SHORT).show();
return;
}

Keep map activity updating in background

In my Android app, I have added a map activity, and I want to be able to monitor the location in background as well and keep updating location data. This data will then be used to perform on location-specific functions.
I am new to Android, so maximum help will be appreciated.
So far, I have the basic code for launching map.
package com.app.alviefinal.alviefinal;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationManager;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.util.Log;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsActivity extends FragmentActivity {
private GoogleMap newmap; // Might be null if Google Play services APK is not available.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
Log.d("Map","MapCreated");
setUpMapIfNeeded();
}
#Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (newmap == null) {
// Try to obtain the map from the SupportMapFragment.
newmap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (newmap != null) {
setUpMap();
Log.d("MAPS","Map working");
}
else Log.d("MAPS","not working");
}
}
private void setUpMap() {
newmap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker").snippet("Snippet"));
// Enable MyLocation Layer of Google Map
newmap.setMyLocationEnabled(true);
// Get LocationManager object from System Service LOCATION_SERVICE
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// Create a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Get the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Get Current Location
Location myLocation = locationManager.getLastKnownLocation(provider);
// set map type
newmap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
// Get latitude of the current location
double latitude = myLocation.getLatitude();
// Get longitude of the current location
double longitude = myLocation.getLongitude();
// Create a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
// Show the current location in Google Map
newmap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
// Zoom in the Google Map
newmap.animateCamera(CameraUpdateFactory.zoomTo(20));
newmap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("My location"));
Log.d("LATITUDE",String.valueOf(latitude));
Log.d("LONGITUDE",String.valueOf(longitude));
GoogleMap.OnMarkerClickListener listener = new GoogleMap.OnMarkerClickListener() {
#Override
public boolean onMarkerClick(final Marker marker) {
Intent intent=new Intent(getApplicationContext(),PrefActivity.class);
startActivity(intent);
return true;
}
};
newmap.setOnMarkerClickListener(listener);
newmap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
#Override
public void onMapClick(LatLng latLng) {
// Creating a marker
MarkerOptions markerOptions = new MarkerOptions();
// Setting the position for the marker
markerOptions.position(latLng);
// Setting the title for the marker.
// This will be displayed on taping the marker
markerOptions.title(latLng.latitude + " : " + latLng.longitude);
// Animating to the touched position
newmap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
// Placing a marker on the touched position
newmap.addMarker(markerOptions);
Log.d("ADDED LATITUDE",String.valueOf(latLng.latitude));
Log.d("ADDED LONGITUDE",String.valueOf(latLng.longitude));
}
});
}
}

You can use Service to get data in the background. For that you have to create a class that extends Service class and then override onStartCommand to write your own code. Something like this:
public class MyService extends Service {
#Override
public IBinder onBind(Intent intent) {
// TODO: Return the communication channel to the service.
throw new UnsupportedOperationException("Not yet implemented");
}
#Override
public int onStartCommand(Intent intent,int flags, int startId) {
...
return START_STICKY;
}
}
You can use timer inside onStartCommand to update your data.
You have to register your service in Android Manifest like this:
<service
android:name=".MyService"
android:enabled="true" >
</service>
You must remember that the service will not start automatically if the phone is restarted. You have to use Boot Broadcast Receiver to start the service.