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?
Related
I don't need to be too precise. I want to know location can be an area of the user in one country. I tried using the location service getLastKnownLocation with the update through GPS. If the getLastKnownLocation is unknown, the time it take to get the result is quite a bit of time. I am working on the weather application, I don't need to have the street name. Is there another way of getting the result more faster.
you can get the last known location for more detail read here last Known Location
or you can request a location updates every period of times you set request locaion updates
it's pretty straightforward
I have referred many questions on this topic, but it seems some of my requirements are missing:
I want to get the GPS location at ~0.0001 accuracy
Don't want to use internet; Though GSM/CDMA network is ok
Should be obtained programmatically when the app starts
Should be quicker, say within a minute (like iPhone, which probably works in Airplane mode as well!)
The code should work in most of the devices
The phone may switch-on/off anytime and travel any distance
Is there any way to get just the co-ordinates with above mentioned requirements? Any sample code snippet will be much appreciated.
Checking various apps like "Locate Me", "Maverick", which claim to show offline locations. But in various scenarios without internet, they don't give track the location (in India).
I have referred plenty of old/new questions inside/outside SO. Below are few:
Is it possible to have the gps location while offline with the nexus
7?
Does GPS require
Internet?
How to get current exact location in android without internet
connection?
[Note: I am asking this question on behalf of my Android team and will be happy to clarify the details if asked for. Should you feel that this post belongs to Android.Stackexchange, then kindly move it.]
1. I want to get the GPS location at ~0.0001 accuracy
You can listen only to GPS provider and discard a location when it doesn't have the minimun accuracy you want:
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 5, myLocationListener); // "myLocationListener" must be an object from a class that implements LocationListener
// "myLocationListener" implementation of LocationListener.onLocationChanged
public void onLocationChanged(Location location)
{
int MIN_ACCURACY = 5; // in metters
if ((!location.hasAccuracy()) || (location.getAccuracy() > MIN_ACCURACY))
{
// discard this location and keep listening to new location readings
}
else
{
// that's a good reading!
// do somethings you want... blah, blah, blah...
// stop updates when you get the location to preserve users' battery.
locationManager.removeUpdates(myLocationListener);
}
}
2. Don't want to use internet; Though GSM/CDMA network is ok
Yes, GPS works totally off-line. Android can make use of internet ONLY to update A-GPS data cache and provide faster reads in cold-start updates.
3. Should be obtained programmatically when the app starts
Then call item locationManager.requestLocationUpdates on mainActivity's onCreate event.
4. Should be quicker, say within a minute (like iPhone, which probably
works in Airplane mode as well!)
Keep in mind that iPhone works with "high quality hardware". Android can be run on crappy devices. So it'll depend of:
The device's hardware quality;
The number of satellites that are visible in the sky at that moment;
The age of almanac and ephemeris data on gps cache;
GPS can fail to read satellites because user is inside a building or something.
5. The code should work in most of the devices
What is the oldest Android's API you want it to run?
6. The phone may switch-on/off anytime and travel any distance
I didn't get it. What is your concern about this?
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Update 1:
"...I would like to use Android 4.0 and above..."
I've tested GPS features from Android 2.3 to 5.0 devices. Everything runs pretty fine on all of them.
"...I have observed that 1 geo-coordinates based demo app which was working in other devices, din't work in my LGG3 with Android 5.0. Any idea on that?..."
Did you check GPS permissions on Android settings? (Maybe it's disabled) Or can be a hardware issue? Did you try in another similar device?
"...Suppose the GPS is showing correct location in New York,
I switch off the phone and then switch on after reaching to London,
then will it still show correct location (without internet)?..."
Sounds you're confusing things: reading a GPS location is one thing. Showing that location into a MAP is another different thing!
You don't need to be connected to the internet to do GPS location reading. But, if you want to show that location into a MAP, probably you're gonna need internet (to load map resources, etc.).
If you nedd to stay collecting GPS locations periodically (let's say, from 10 to 10 minutes), then it will be better to use AlarmManager to schedule a timer that will "finger" your app and say "hey, time to make a GPS reading!".
"...Also what is your opinion about the latest Fused API?..."
I've tested it and used it for a while, but I gave it up. It needs that Google Play Services be installed to work (not a problem, most users have it on their devices). But if you need ACCURACY (as I do), it will not work. It uses "fused sensors" (accelerometer, gps, wifi, compass, etc...) to try to get user location with minimum power possibile. Sometimes, it says you're 10 miles away from where you're really is. I couldn't make it work fine to keep the "path" where user has been. But it really saves battery.
Suggestion is to use Google Location Services
It takes the best possible and accurate location as accurate as it can at current moment. It automatically (with configuration of course) takes best current accuracy too - whatever is available GPS, network, internet, GSM/CDMA/LTE... It also cashes last known location so, basically, you know it every moment - the best what you can.
Of course you have to realize that each service provides its own accuracy and in it's own time. Look, for example, GPS Test App on Android and see how accuracy increases with time and used satellites.
Also Location Services is good for you because it simply provides coordinates - just as you asked and hides a lot of work to determine what real service to use based on time and accuracy. However, of course, if none of the services on your particular device and location can give you required accuracy then there is no way to get it. That's why services also provide accuracy measurement.
Here is another link
Use fused location API provided by Android SDK.Implement fused location in a Service and call it in your application MainActivity.
I have an Android app where I should somehow clearly distinguish between whether user has not moved for an amount of time or location was not resolved during that interval. As I understand in both cases I will not receive any update if I requestLocationUpdates().
Does anybody has an idea on how to implement this?
The sample case is:
I've got 2 valid and accurate locations: 1 from GPS and 1 from network; Good, that's exactly what I need.
One minute has passed: the user may have gone to a kind of underground station and lost gps/network (and ability to resolve location) OR may have not moved at all;
Now I have to decide whether the location is perfectly relevant (user not moved) or I have no location at all (all providers lost). But how? Seems like in both cases I receive no location updates.
Try using LocationClient.getLastLocation. You can store this location and check against it later.
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.
I am building an app that can use a user's current location on certain actions. Location is more of a benefit to the user rather than a critical part of the process. I'm only interested in very rough accuracy and it can be off by 5 or even 10 miles and still be of value. General plan was to see if the network provider was enabled and then just do
locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER)
Assuming that no other apps are running, will the phone automatically periodically update the network location? I.e. there will likely always be a value returned by this code which will meet my needs?
EDIT:
I've been doing a bit more research and I think the question I was really trying to ask here was if the Android operating system or the phone itself would update the last known location for the network provider as the phone locked onto different cell phone towers or wifi networks. The answer appears to be no. After force stopping all apps on my phone which I know to interaction with location services, the last known location has stopped updating. So, I'm guessing that these days chances are that most phones will have some location services running in the background updating the last known location but the phone itself won't do it. Hence I think I'll be going with some form of requesting location updates if the last known location is too old.
getLastKnownLocation() only returns the last fix. So if no location providers are being updated the return value of getLastKnownLocation() will not change. The location object will also provide you with accuracy and time of the fix.
I would look at this post for more information. You could use some version of the one shot location.
http://android-developers.blogspot.com/2011/06/deep-dive-into-location.html
Frohnzie is correct about getLastKnownLocation. Getting location is an expensive operation, so it only happens when an app requests it. I've often driven 30 miles or so, opened the foursquare app on my phone, and it showed me venus that were 30 miles away. Clearly they were using getLastKnownLocation.
For your use case, I would recommend LocationManager.requestLocationUpdates. You can specify an accuracy and a timeout. So if the phone can't quickly find a rough estimate of the user's location, you can just forego location since it is not crucial to your application.