Develop Reference

Getting location offline

I want to get the value of Longitude and Latitude of my current locatoin when offline and save the current location to its database. Is it possible to get the longitude and latitude of the device when mobile data and wifi are off but the GPS is ON?

Just use this code. Make sure the user hasn't selected wifi only or network only option in his location setings. it has to be high accuracy or GPS only. This piece of code will work.
public class Location extends AppCompatActivity {
LocationManager locationManager;
Context mContext;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_location);
mContext=this;
locationManager=(LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates( LocationManager.GPS_PROVIDER,
2000,
10, locationListenerGPS);
isLocationEnabled();
}
LocationListener locationListenerGPS=new LocationListener() {
#Override
public void onLocationChanged(android.location.Location location) {
double latitude=location.getLatitude();
double longitude=location.getLongitude();
String msg="New Latitude: "+latitude + "New Longitude: "+longitude;
Toast.makeText(mContext,msg,Toast.LENGTH_LONG).show();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
};
protected void onResume(){
super.onResume();
isLocationEnabled();
}
private void isLocationEnabled() {
if(!locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
AlertDialog.Builder alertDialog=new AlertDialog.Builder(mContext);
alertDialog.setTitle("Enable Location");
alertDialog.setMessage("Your locations setting is not enabled. Please enabled it in settings menu.");
alertDialog.setPositiveButton("Location Settings", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
Intent intent=new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
});
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
dialog.cancel();
}
});
AlertDialog alert=alertDialog.create();
alert.show();
}
else{
AlertDialog.Builder alertDialog=new AlertDialog.Builder(mContext);
alertDialog.setTitle("Confirm Location");
alertDialog.setMessage("Your Location is enabled, please enjoy");
alertDialog.setNegativeButton("Back to interface",new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog, int which){
dialog.cancel();
}
});
AlertDialog alert=alertDialog.create();
alert.show();
}
}
}
The parameters of requestLocationUpdates methods are as follows:
provider: the name of the provider with which we would like to register.
minTime: minimum time interval between location updates (in milliseconds).
minDistance: minimum distance between location updates (in meters).
listener: a LocationListener whose onLocationChanged(Location) method will be called for each location update.
Permissions:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
Add above permissions to manifest file for the version lower than lollipop and for marshmallow and higher version use runtime permission.

What do I see the GPS icon consistently?

I've written my custom location manager to check for an update in the user's location every 30 seconds. The code is working fine i.e. I'm receiving updates in user's location. But the problem is that the GPS icon is always visible on the status bar on top. I'm guessing that it should be visible only once in 30 seconds. Is this normal or I'm doing something wrong?
public volatile Double mLatitude = 0.0;
public volatile Double mLongitude = 0.0;
int minTime = 30000;
float minDistance = 0;
MyLocationListener myLocListener = new MyLocationListener();
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setSpeedRequired(false);
String bestProvider = locationManager.getBestProvider(criteria, false);
locationManager.requestSingleUpdate(criteria, myLocListener, null);
locationManager.requestLocationUpdates(bestProvider, minTime, minDistance, myLocListener);
private class MyLocationListener implements LocationListener {
#Override
public void onLocationChanged(Location loc)
{
if (loc != null) {
//Do something knowing the location changed by the distance you requested
mLatitude = loc.getLatitude();
mLongitude = loc.getLongitude();
Toast.makeText(mContext, "Location Changed! "+Double.toString(mLatitude)+" "+Double.toString(mLongitude), Toast.LENGTH_LONG).show();
}
}
#Override
public void onProviderDisabled(String arg0)
{
//Do something here if you would like to know when the provider is disabled by the user
Toast.makeText(mContext, "Provider Disabled! "+Double.toString(mLatitude)+" "+Double.toString(mLongitude), Toast.LENGTH_LONG).show();
}
#Override
public void onProviderEnabled(String arg0)
{
//Do something here if you would like to know when the provider is enabled by the user
Toast.makeText(mContext, "Provider Enabled! "+Double.toString(mLatitude)+" "+Double.toString(mLongitude), Toast.LENGTH_LONG).show();
}
#Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2)
{
//Do something here if you would like to know when the provider status changes
Toast.makeText(mContext, "Provider Status Changed! "+Double.toString(mLatitude)+" "+Double.toString(mLongitude), Toast.LENGTH_LONG).show();
}
}

As long as 1 or more apps have called requestLocationUpdates for the GPS provider, GPS will stay on. It doesn't turn off between requests. It can't- doing so would cause it to lose satellite lock, which would cause it to have to re-establish. That takes a lot more than 30 seconds sometimes. So GPS will stay on until you unregister for GPS events.

The question is old but still, it would be great to give a better answer.
You need to use a Handler which runs continuously on 5 minutes interval so, you get the location update only once and you release the GPS device, this way your app won't listen to the GPS updates but your handler know when it should be called again to listen the updates.
public static void getLocation(Context context) {
Handler locationHandler = new Handler();
locationHandler.post(new Runnable() {
#Override
public void run() {
LocationManager locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestSingleUpdate(LocationManager.GPS_PROVIDER, new LocationListener() {
#Override
public void onLocationChanged(Location location) {
// Handle the location update
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
#Override
public void onProviderEnabled(String provider) {
}
#Override
public void onProviderDisabled(String provider) {
}
}, null);
locationHandler.postDelayed(this, 1000 * 60 * 5);
}
});
}

How to observe Gps Provider continually?

I want to know when the GPS on the device is tuned on, and the location is changed.
Here is what I've done:
LocationManager mlocManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
LocationListener mlocListener = new MyLocationListener();
mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
public class MyLocationListener implements LocationListener
{
#Override
public void onLocationChanged(Location loc)
{
Toast.makeText( getApplicationContext(),"onlocation changed",Toast.LENGTH_SHORT).show();
}
#Override
public void onProviderDisabled(String provider)
{
Toast.makeText( getApplicationContext(),"providerdisabled",Toast.LENGTH_SHORT).show();
}
#Override
public void onProviderEnabled(String provider)
{
Toast.makeText( getApplicationContext(),"provideenabled",Toast.LENGTH_SHORT).show();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
}
}
It is working fine when my app runs in the foreground, but when I close it, I won't get any more updates. I'd like to know how to get this information continuosly until my application is uninstalled.

You need to put this in a service and start the service sticky.
Also you should think about using the FusedLocationManager by using GooglePlayServices.
For more info about GooglePlayServices and locations read here

How to get user's GPS coordinates by clicking a button

i want to make application like this :
User clicks the button
The application show the user's coordinates (Latitude and Longitude)
i'm following the steps here
// Acquire a reference to the system Location Manager
LocationManager locationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
LocationListener locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
// Called when a new location is found by the network location provider.
double glat = location.getLatitude();
double glong = location.getLongitude();
Toast.makeText(getApplicationContext(), "Your position\n"+glat+"\n"+glong, Toast.LENGTH_LONG).show();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
#Override
public void onProviderEnabled(String provider) {}
#Override
public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
how to implement it to button click event?
if the user clicks the button, the toast appear showing the position :)
UPDATE
I implement it using startActivityForResult() but the result is empty or null
here's my code :
this is the code on the button that i want to click
btn_obj_useKor.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
Intent intent = new Intent(getApplicationContext(), MyLocationListener.class);
startActivityForResult(intent, 0);
}
});
and this is my MyLocationListener class :
public class MyLocationListener extends Activity{
Intent intent;
String output = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
LocationManager locationManager = (LocationManager) getApplicationContext().getSystemService(Context.LOCATION_SERVICE);
LocationListener locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
double glat = location.getLatitude();
double glong = location.getLongitude();
output = glat+","+glong;
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
#Override
public void onProviderEnabled(String provider) {}
#Override
public void onProviderDisabled(String provider) {}
};
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
intent.putExtra("returnedData", output);
setResult(RESULT_OK, intent);
finish();
}
}
When i click the button it showing WTF! that means the result is null or empty.
what's the problem and what should i do then?

It wont return a result immediately since it takes time for the GPS provider to start and find your location. This is why you listen for a callback event.
Currently your code is listening for the network location, which is not very accurate. Change the LocationManager to GPS_Provider (on your last line) to use GPS if it is enabled.

Responding to an onClick is a user event, the LocationListener onLocationChanged is also an event. If you trigger the user event before the LocationListener event, there will be no position available to display.
My suggestion is to call startActivityForResult on another activity in the button onClick handler, the 2nd activity has all the LocationManager & LocationListener code in it, in the onLocationChanged event handler you pass the position back to the 1st activity.

How to determine whether GPS position has been acquired on android?

Let's say I have a button which calls another activity only if the system knows the EXACT user's location. I made a dialog to ask the user to turn on GPS if it's disabled, but when the user enables GPS and pushes the button again, I will probably not have the exact location yet. Can anyone help me with this ?

You need to create a LocationListener, and wait for the callback. It is pretty well described in the api docs:
// Acquire a reference to the system Location Manager
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
// Define a listener that responds to location updates
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
// When you get here you have a location...
useTheNewLocationToEnableTheButton(location);
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
// Register the listener with the Location Manager to receive location updates
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);

You can listen for GpsStatus events, to make sure that user actually enabled GPS (GPS_EVENT_STARTED), and to be notified when GPS gets position fix (GPS_EVENT_FIRST_FIX).

If you don't know coordinates, the best way is to display a ProgressDialog while retrieving a location and, when you got it, dismiss ProgressDialog and launch your activity.
final LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
//here you can get coordinates via location.getLongitude() and
//location.getLatitude() methods, dismiss the progress dialog and
//start your activity
locationManager.removeUpdates(this);
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
public void onProviderEnabled(String provider) {}
public void onProviderDisabled(String provider) {}
};
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);