There are a number of workarounds for detecting the possibility of a fake location being returned by the LocationManager API. those include checking if the mock location setting is enabled and checking the list of installed apps for the ones using the mock location permission. if any of the above happens we could go with removing the TestProvider from the current LocationManager instance and getting a location again, just in case the api returns bogus results. however the above approach wont work with the FusedLocationAPI. is it always granted to return the real location ? or should i consider changing my code to use the LocationManager ?
because of the nature of product i'm working on, it is necessary to be sure of the location.
thanks in advance
I've been working on an app that needs to be location-aware, and I've noticed that there are two (or more) methods of receiving location: with Google Play services (as seen here developer.android.com/training/location/retrieve-current.html#GetLocation) and with Location Manager, Providers etc. (as seen here http://www.vogella.com/tutorials/AndroidLocationAPI/article.html#locationapi_criteria).
What is the difference between these methods (if there is any)? Which one is more accurate?
edit: ok, I see that I sent the wrong link on the first thing. Won't this code (http://developer.android.com/training/location/receive-location-updates.html) give me location updates? Generally, what's the most accurate way to get my location?
The one with the GPS is accurate and that which is based on Network is not. Google Play Service use FUSE api to get the GPS location first, if the location is found (that's great), otherwise it will try to get location fix from Network Tower. In Short the one with GPS is accurate
The first method provides the details of LastKnownLocation. ie. the last location received from GPS or network provider when you or other apps accessed the location services. After that there are chances you moved a lot and it need not be your current location. So if You are planning to create an application that requires accurate location tracing, You should fetch the location as in the "Vogella" method. If the current location is unavailable, you can try using the last known location (As a plan B :-)).
After few hours of testing outside of house, when i came back to my house i found that GPS is enabled but was not getting location fixes inside the building.Hence its onLocationChanged method couldn't get called.
Problem: How to know that GPS is not getting any location fixes as device continue to sense your location in "trying mode".By trying mode i mean the situation where it is not coming to any result even after 20 to 30 minutes still it declared it self as enabled (blinking in status bar).
How one could know that the GPS doesn't get location so switch to another provider like Network_Provider.
In short i want to get my device to conclude something that GPS can find location fix for sure or you have to take location by another means.
I hope at least someone can give me idea about how to deal with that.
The link below has an awesome tutorial, of how to get the location from GPS and/or Network.
It uses a timer task, which analyzes if there is a GPS location in a specific period of time, assume 20 seconds. If not, it will return the location from Network as the current location. If there is a location from GPS, then it will compare which update is new (latest), and return that.
What is the simplest and most robust way to get the user's current location on Android?
I have a Service implementing LocationListener listening for both GPS and Network.
The application is dependant on a constant location-feed, but it seems when GPS has a hard time getting a locationfix network location doesnt step in.
manager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000 * 30,0, LocationReporterService.this);
manager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 1000 * 60 * 2,0, LocationReporterService.this);
Questions
How do I make sure that I always get a location?
How can I make sure that if I dont get a GPS-location, I get a Network-location?
Is it a known bug?
Should I have 2 services, GPSLocationService and NetworkLocationsService?
Is there a solution to this? :)
I agree with most of comments from AlexBottoni good answer, although in some points I can't suppot him.
Overview
First, just to check that you are doing it right...
You setup the same LocationListener for both providers. To indentify from where you are reciving the location you need to test it like this:
public void onLocationChanged(Location fix) {
if(fix.getProvider().equals(LocationManager.GPS_PROVIDER)){
//here Gps
} else if(fix.getProvider().equals(LocationManager.NETWORK_PROVIDER)){
//here Network
}
Also, you setup a different acquisition frequency. Gps is providing a new location every 30 seconds and Network every 2 minutes.
As you didn't impose a minimum distance, you should receive a new Location from each one of the providers (as long as they can get a fix) with the frequency requested. If you don't receive a fix, is because they weren't able to acquire one.
Also, it may takes a little longer then requested to get the fix (mainly with Gps), because it may take some time to shyncronize with satellites and fix a location.
Fallback
There is no builted-in fallback from one provider to the other. They are independet, as said by Alex. I'm using the following approach to implement fallback:
Register Gps listener and start a timer
On every GPS location, restart timer
If timer reachs end, register Network listener (Gps listener keeps registered)
If new Gps location arrives, unregister Network listener, restart timer
Preferable Provider
Although Gps may not be available everyhere, is far most precise then Network. In my town, I get 6 meters accuracy with GPS and 1 Km with Network :-(
Two services
Doesn't matter where you register the listener, activity or service, separate ot together, as long as you request them and the provider can get a fix, you will get the location (assuming no bugs in application :-))
Final Notes
Ensure you have the permissions need (ACCESS_FINE_LOCATION, INTERNET, etc).
Ensure that phone setup have Network Location enabled (usually default is disable)
Most Gps receivers support updating information about satellite location, which improves fix time. You can use GPS Satus from the market, to do it.
Regards.
This is really weird because, AFAIK, Android does not fall back to the second choice (network location provider) only if and when the first one (GPS) does not work. The two location providers are indipendent and should be sending location updates to you listeners indipendently to each other. Hence, the first one (GPS) should not be able to block the second one (network) in any case.
Regarding your questions:
How do I make sure that I always get a location?
You don't. There is no way to be sure. There are cases in which you cannot get any location fix just because no location reference is available. This is often the case in metro/underground stations. No GPS, no cellular antennas (not everybody lives in NYC or London...), no wi-fi hotspots so no way to determine your current position. Believe it or not, in the new hospital of my town, we have this situation at the moment because GPS constellation is not visible (indoor...), no wi-fi hotspots have been installed yet and the only available CellID antenna is just a few hundred meters away so you get the same signal everywhere, both outside and inside the building.
How can I make sure that if I dont get a GPS-location, I get a Network-location?
You cannot, either. It depends on the available networks. Anyway, you can check what you get from the location providers in your code and switch from one to the next until you get a usable location fix.
Is it a known bug?
No, it is not a bug. It is more a known limit of the existing technology.
Should I have 2 services, GPSLocationService and NetworkLocationsService?
It is something to try. As nick already said, this should not be a problem but a check should not hurt.
Is there a solution to this? :)
If your app is intended to be used mainly in a urban environment (a town), most likely you should use the network location engine as your main location engine. Nowadays, every village and town is covered by a large set on cellular phone antennas and by a large set of wi-fi hotspot so you are more likely to get a good location fix from the network location provider than from the GPS one. This is particularly true in towns with high buildings and narrow roads (that does not just mean NYC. Even here in Venice we have problems with the GPS). The network engine is also faster in getting a first fix and works indoor as well.
Fall back to GPS only if and when the network location engine does not work.
Does it give the user's current location if the device is online? How does it determine the last known location?
LocationManager docs
Taken from the docs & reworded
getLastKnownLocation returns the last known location fix obtained from the given provider.
The device does not need to start a provider to get this information so good for battery life.
However, if the users phone has been sleeping or turned off and has moved the location will be out-of-date.
If you need the location to be up-to-date I wouldn't use this method, instead request a single update, depending on your applications requirements.
Note: requesting location updates from an available provider will effect the users battery life if used irresponsibly