Develop Reference

How to make sure that getLastLocation().isSuccessful()

Im trying to getLastLocation(), but sometimes it is null. When that happens, I go to google maps just for a second, and return to my app and in 99% that will do. There is also one app that just returns city that you're in and it works even if my app can't getLastLocation(). I've noticed that when I use that other app, or google maps, or weather app, for a short time location icon will appear in status bar, but when I use my app that icon never appears, so I'm guessing that may be the problem?
What I need to do to assure that I get my location to be != null?
One more thing, sometimes I get my location (lat and long), but reverse geocoding goes to catch because List is empty? How to make sure it always is not empty?
The code that I use is just a copy/past from android developers.

If you are using Android Emulator it is expected that the location doesn't get updated unless you open the Maps App.
To ensure you get non-null location you need to request for location updates
You can do something like this
#SuppressLint("MissingPermission")
private fun getLastKnownLocation() {
// get last known location from fusedLocationProviderClient returned as a task
fusedLocationProviderClient.lastLocation
.addOnSuccessListener { lastLoc ->
if (lastLoc != null) {
// initialize lastKnownLocation from fusedLocationProviderClient
lastKnownLocation = lastLoc
} else {
// prompt user to turn on location
showLocationSettingDialog()
// when user turns on location trigger updates to get a location
fusedLocationProviderClient.requestLocationUpdates(
locationRequest, locationCallback, Looper.getMainLooper()
)
}
// in case of error Toast the error in a short Toast message
}
.addOnFailureListener {
Toast.makeText(requireActivity(), "${it.message}", Toast.LENGTH_SHORT).show()
}
}
This is just a stub, you will need to handle permissions, create FusedLocationProviderClient, LocationRequest and LocationCallbackObject.
You may also need to prompt the user to Turn on Location Settings.
Please show us your GeoCoding code to elaborate further.

Android get high resolution location info on button press

I have read the Android Docs, FusedLocationProvider vs LocationManager; perused the dizzying array of questions and answers around this topic here in stackoverflow; and developed many tests with poor results so far. Why is this so darned confusing and hard to grasp?
I have an app that needs to get a hi-res Location object (lat/long/alt/accuracy/etc) when the user performs an action in the app; let's say they press a button. What is the best way to do this?
I have used the fusedLocationProviderClient.getLastLocation().addOnSuccessListener() and get wildly mixed results.
I have used locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER). If I start the GPS Status app on my Galaxy S9 then this produces quite wonderful results. But if that is not running, then the results are worthless.
What am I missing here? Everyone likes to point to this Doc site or that Example site that is mostly worthless and doesn't really answer this specific question. I have wasted hours pouring over those sites that simply don't answer this question. Please, just sum up the general algorithm that should be used here and the calls to make. That is all I need.
I want to be able to walk around in my yard (10 meters here and there) and press the button and have the app show the lat/long/accuracy/altitude/distance-from-last-location and have it be correct every time within a certain level of accuracy. What do I have to do? I need hi-res accuracy, but the ability to notify the user of accuracy less than say 100ft, and still obtain the best accuracy possible even if it has an error of 400ft.

You are missing how GPS receivers work.
When there is no app using precise location, all smartphones turn off the GPS receiver to conserve battery power.
Even if you selected location services to be on (in settings), you will notice in the notification bar the icon for GPS use is only present when an app is active, like Google Maps or GPS test app.
Once the receiver is turned on (because some app needs it), it takes some time before a "fix" - accurate location measurement is available.
How long it will take to get a fix depends on several things, including environmental conditions, your phone type, time and distance since last accurate fix, etc.
It may take anywhere from several seconds to sever minutes.
So, what you should do, is subscribe to location as soon as your app is opened, and request to receive it as frequently as possible.
Then, enable the button only once you have good accuracy, and when the button is pressed, show the latest result.
You should probably also display some spinner or message to the user while waiting for accurate fix so the user knows your app is not stuck.
Edit: by "subscribe" I mean register the necessary callback so your app will receive the location from the system when it is ready.
How to do this, depends on which API you choose.
There is no error in the google docs.
If you choose to use fused location, you will need to do the following:
Create a location request object and set priority to PRIORITY_HIGH_ACCURACY, also setInterval and setFastestInterval to 1000 (1 second) to get the best accuracy.
Get a FusedLocationProviderClient object from LocationServices
Use the client to register a callback to your app
There are code examples here:
https://developer.android.com/training/location/request-updates
In the callback function in your app you can check the accuracy, and if it is good enough for you enable the button and save the location so you can display it to the user when they click the button.

Ok - this seems to work. This general flow seems to be the answer.
Assumptions: you are requesting android.permission.ACCESS_FINE_LOCATION or ACCESS_COARSE_LOCATION in manifest.
Just sample code in the onCreate() function of MainActivity for testing purposes.
check to see if we have ACCESS_FINE_LOCATION permission; if not, request.
get FusedLocationProviderClient
get a start location from getLastLocation(); for purposes of comparison and start of track
define locationCallback() to be called by fusedLocationProvider; all we are interested in is getting the last one in the stack and save to class Field.
define LocationRequest with interval of 5 secs and PRIORITY_HIGH_ACCURACY
check to see if the user device is allowing this; not sure what to do with this other than to notify user if not allowed.
now requestLocationUpdates using the LocationCallback defined above.
when user performs action needing current lat/long (e.g. press button), retrieve class field populated with Location object on last LocationCallback().
I am very open to feedback on this pattern. Hope it helps others (as there is a plethora of questions about this). And would love to hear about any problems with this design or issues that I may encounter.
if (Build.VERSION.SDK_INT >= 23) {
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_CODE_ASK_PERMISSIONS);
} else {
// getFusedLocationProviderClient
fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
// getStartLocation
fusedLocationProviderClient.getLastLocation().addOnSuccessListener(this, new OnSuccessListener<Location>() {
#Override
public void onSuccess(Location location) {
if (location != null) {
StartLocation.set(location);
}
}
}).addOnFailureListener(this, new OnFailureListener() {
#Override
public void onFailure(#NonNull Exception e) {
Toast.makeText(MainActivity.this, e.getMessage(), Toast.LENGTH_LONG).show();
}
});
// Define LocationCallback
locationCallback = new LocationCallback() {
#Override
public void onLocationResult(LocationResult locationResult) {
if (locationResult != null) {
LastLocation = locationResult.getLastLocation();
}
}
};
// Now lets request location updates - that is how this must happen
// https://developer.android.com/training/location/change-location-settings
LocationRequest locationRequest = LocationRequest.create();
locationRequest.setInterval(5000);
locationRequest.setFastestInterval(1000);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
// Attempt to see if requested settings are compatible with user device.
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
builder.addLocationRequest(locationRequest);
// Check to see if location settings are satisfied by user's device settings?
SettingsClient client = LocationServices.getSettingsClient(this);
Task<LocationSettingsResponse> locationTask = client.checkLocationSettings(builder.build())
.addOnSuccessListener(this, new OnSuccessListener<LocationSettingsResponse>() {
#Override
public void onSuccess(LocationSettingsResponse locationSettingsResponse) {
}
}).addOnFailureListener(this, new OnFailureListener() {
#Override
public void onFailure(#NonNull Exception e) {
if (e instanceof ResolvableApiException) {
// Location settings are not satisfied, but this can be fixed
// by showing the user a dialog.
}
Toast.makeText(MainActivity.this, "Location Settings Are Not " +
"Correct On This Device", Toast.LENGTH_LONG).show();
}
});
// Request location updates
fusedLocationProviderClient.requestLocationUpdates(locationRequest, locationCallback, Looper.getMainLooper());
}
}

LocationAvailability No Location Available

Google's FusedLocationProviderApi for Android was recently deprecated within the past few months, with FusedLocationProviderClient being its successor so I recently updated the location APIs used in my client's app to use the new ones.
Every time onLocationAvailability is fired in LocationCallback I notify the user when locationAvailability.isLocationAvailable() returns false, but it appears that this condition occurs more often than I expected on some devices. I run these location updates inside a foreground Service and it is crucial that these location updates remain consistent. Is there a way to determine the cause of this failure so
We don't indicate any false positives to the end-user
We can try to fix the issue or at least report to the end-user what they should do?
It appears to me that either the deprecated APIs provide more insight into these issues since it was used in conjunction with GoogleApiClient or perhaps I'm missing some smaller details.

I went through the same issue. And after three days of trying things out, I got to work on it out.
I also had to collect a location in a foreground state like you, and if the foreground service was destroyed, I had to unregister.
The first mistake I made was not to guarantee that removeLocationUpdates would be run on the same thread as the requestLocationUpdates. Actually, it doesn't have to be the same thread, but after a requestLocationUpdates, you must call removeLocationUpdates to make the next requestLocationUpdates valid. To ensure this, it is much easier to work on the same thread.
For example:
private fun FusedLocationProviderClient.requestLocation(
request: LocationRequest
): Single<LocationResult> {
return Single.create<LocationResult> { emitter ->
requestLocationUpdates(request, object : LocationCallback() {
override fun onLocationResult(result: LocationResult?) {
removeLocationUpdates(object : LocationCallback() {})
.addOnCompleteListener {
if (emitter.isDisposed) {
info("onLocationResult called after disposing.")
return#addOnCompleteListener
}
if (result != null && result.locations.isNotEmpty()) {
onSuccess(result)
} else {
onError(RuntimeException("Invalid location result"))
}
}
}
private fun onError(error: Exception) {
if (!emitter.isDisposed) {
emitter.onError(error)
}
}
private fun onSuccess(item: LocationResult) {
if (!emitter.isDisposed) {
emitter.onSuccess(item)
}
}
}, Looper.getMainLooper())
}
}
As the code suggests, I have attracted Single's emitter to the addOnCompleteListener in removeLocationUpdates to ensure the call of removeLocationUpdates behind the requestLocationUpdates. Without RxJava, of course, it would be easier to implement.
The second mistake I made was the wrong interval setting in LocationRequest. According to the doc:
This method sets the rate in milliseconds at which your app prefers to receive location updates. Note that the location updates may be somewhat faster or slower than this rate to optimize for battery usage, or there may be no updates at all (if the device has no connectivity, for example).
The explanation is unkind but ultimately, if you call requestLocationUpdates once, you must have a Location update event triggered by interval before the next requestLocationUpdates. Finding this bug was the hardest.
The third mistake I made was to set the wrong priority in LocationRequest. In API 10 and below, it was not PRIORITY_BALANCED_POWER_ACCURACY but it was resolved by using PRIORITY_HIGH_ACCURACY. In this case, I have only tested on the emulator, so the actual device may have different results. I guess PRIORITY_BALANCED_POWER_ACCURACY doesn't seem to work properly because the emulator doesn't provide Bluetooth hardware.
So my LocationRequest looks like:
LocationRequest.apply {
priority = PRIORITY_HIGH_ACCURACY
interval = 10000L
}
I hope the three mistakes and solutions I made is helpful to you!

As official documentation says:
onLocationAvailability Called when there is a change in the
availability of location data. When isLocationAvailable() returns
false you can assume that location will not be returned in
onLocationResult(LocationResult) until something changes in the
device's settings or environment. Even when isLocationAvailable()
returns true the onLocationResult(LocationResult) may not always be
called regularly, however the device location is known and both the
most recently delivered location and getLastLocation(GoogleApiClient)
will be reasonably up to date given the hints specified by the active
LocationRequests.
So this method does not provide information about reason.
We don't indicate any false positives to the end-user
Currently I just ignore result of this method because it returns false too often, and then again true, and so on.
We can try to fix the issue or at least report to the end-user what they should do?
Check if Location Services are enabled (using LocationManager.isProviderEnabled())
Check if you have permissions, request them if needed (docs)

I filter false positives of locationAvailability.isLocationAvailable() by calling this piece of code, which checks if location service is enabled.
fun isLocationEnabled(): Boolean {
return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
val lm = context.getSystemService(Context.LOCATION_SERVICE) as LocationManager
lm.isLocationEnabled
} else {
val mode = Settings.Secure.getInt(
context.contentResolver, Settings.Secure.LOCATION_MODE,
Settings.Secure.LOCATION_MODE_OFF
)
mode != Settings.Secure.LOCATION_MODE_OFF
}
}
override fun onLocationAvailability(p0: LocationAvailability?) {
if (isLocationEnabled().not()) {
locationUpdateSubject.failed(LocationAvailabilityError)
}
}

as Google docs says:
When isLocationAvailable() returns false you can assume that location
will not be returned in onLocationResult(LocationResult) until
something changes in the device's settings or environment.
So you can assume that location may be not available not only because of disabled location settings, but because of signal strength, or maybe satellites are not visible or something else, it just indicates that you will not receive location updates until something changes. You can show user notification about it with something like "We can't get your location, try enable location settings"

I've faced same issue and same time I saw that location services has been enabled on the device and my ap had allowed permissions from user.
I still saw
com.google.android.gms.location.LocationCallback#onLocationAvailability LocationAvailability[isLocationAvailable: false]
The issue was that there is additional preference inside Location item on the phone. We have to choose Battery saving/High accuracy option. Please check out the screenshot provided:

Detecting Mock Location Not Working (Android)

I'm trying to set some protection against people using mock locations to manipulate my app. I realise that it's impossible to prevent 100%... I'm just trying to do what I can.
The app uses Google location services (part of play services) in its main activity.
The onLocationChanged() method is:
public void onLocationChanged(Location location) {
this.mCurrentLocation = location;
if (Build.VERSION.SDK_INT > 17 && mCurrentLocation.isFromMockProvider()) {
Log.i(TAG, "QQ Location is MOCK");
// TODO: add code to stop app
// otherwise, currently, location will never be updated and app will never start
} else {
Double LAT = mCurrentLocation.getLatitude();
Double LON = mCurrentLocation.getLongitude();
if ((LAT.doubleValue() > 33.309171) || (LAT.doubleValue() < 33.226442) || (LON.doubleValue() < -90.790165) || (LON.doubleValue() > -90.707081)) {
buildAlertMessageOutOfBounds();
} else if (waiting4FirstLocationUpdate) {
Log.i(TAG, "YYY onLocationChanged() determines this is the FIRST update.");
waiting4FirstLocationUpdate = false;
setContentView(R.layout.activity_main);
startDisplayingLists();
}
}
}
The location services work perfectly and all is well with the app in general, but when I run the app in an emulator with Android Studio (Nexus One API 23), and I set the location using extended controls (mock), the app just continues to work as normal, and so it seems that the condition:
if (Build.VERSION.SDK_INT > 17 && mCurrentLocation.isFromMockProvider())
Is returning false.
This doesn't make any sense to me. Does anyone know why this would happen?
Thanks!

The short answer: .isFromMockProvider is unreliable. Some fake locations are not properly detected as such.
I have spent an extensive amount of time researching this and written a detailed blog post about it.
I also spent time to find a solution to reliably suppress mock locations across all recent/relevant Android versions and made a utility class, called the LocationAssistant, that does the job.
In a nutshell (using the aforementioned LocationAssistant):
Set up permissions in your manifest and Google Play Services in your gradle file.
Copy the file LocationAssistant.java to your project.
In the onCreate() method of your Activity, instantiate a LocationAssistant with the desired parameters. For example, to receive high-accuracy location updates roughly every 5 seconds and reject mock locations, call new LocationAssistant(this, this, LocationAssistant.Accuracy.HIGH, 5000, false). The last argument specifies that mock locations shouldn't be allowed.
Start/stop the assistant with your Activity and notify it of permission/location settings changes (see the documentation for details).
Enjoy location updates in onNewLocationAvailable(Location location). If you chose to reject mock locations, the callback is only invoked with non-mock locations.
There are some more methods to implement, but essentially this is it. Obviously, there are some ways to get around mock provider detection with rooted devices, but on stock, non-rooted devices the rejection should work reliably.

location.getLocation() when GPS is enabled but can't reach satellite

I have a working app that sorts places by distance from my location or alphabetically if the user does not want to enable GPS. Everything works well, but I would like to enhance my app by automatically sorting alphabetically if a satellite can not be reached, say from a basement, or if it is just taking over a given period of time, say 5 seconds. Is this even possible? I haven't been able to find anything like this. I'd like to just pop up a message that says "Can't reach satellite, sorting alphabetically" instead of the user having to do anything themselves.
Thanks for your responses and your time.
Mike

You should override your LocationListener's onStatusChanged() callback:
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
if (provider.equals(LocationManager.GPS_PROVIDER)){
if (status == LocationProvider.OUT_OF_SERVICE || status == LocationProvider.TEMPORARILY_UNAVAILABLE){
// GPS unavailable: send notification
} else {
// you're out of a basement, continue using GPS
}
}
}
Android documentation promises that if a provider is unavailable at the moment you subscribe your LocationListener, it invokes this callback immediately.

Why not use some combination of Out of Service and Temporarily Unavailable in the Location Listener's onStatusChanged()?
http://developer.android.com/reference/android/location/LocationListener.html