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Android Location Object Always Null

I'm simply trying to write a method that returns Latitude and Longitude. I have an activity with a button and two text fields. The java class I am using extends AppCompatActivity and implements LocationListener When the button is pressed the following method is pressed:
public void startGPS(View view)
{
// Here is the code to handle permissions - you should not need to edit this.
if ( Build.VERSION.SDK_INT >= 23 &&
ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED &&
ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[] { android.Manifest.permission.ACCESS_FINE_LOCATION, android.Manifest.permission.ACCESS_COARSE_LOCATION }, TAKE_PHOTO_PERMISSION);
}
Location location = locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 5000, 0, this);
}
Later on I try to print out my location in my onLocationChanged method but it was causing the app to crash. I ran it through the debugger and found that the location was always null.
I tried to this solution but it didn't work. Other examples are calling the function in onResume but I really need this to be in startGPS method.
Also, is there a chance that the error is just with my device? I'm running it on a Nexus 7 which doesn't seem to have any problems when I run Google Maps.

If are trying to return the GPS Coordinates after pressing a button that chances are you don't already have an existing GPS location stored. You should be using requestLocationUpdates and not getLastKnownLocation.
locationManager.requestLocationUpdate(LocationManager.NETWORK_PROVIDER, 5000, 0, locationListener)
When you use requestLocationUpdate it will automatically call onLocationChanged for you so you don't need to call it in your code.
You can substitute LocationManager.NETWORK_PROVIDERfor LocationManager.GPS_PROVIDER but as long as you have a WiFi connection you should be able to get coordinates.

If you are trying to use this inside try switching GPS_PROVIDER to NETWORK_PROVIDER; this will work anywhere that the phone has service.

Because Android doesn't track location when no app is requesting it, in order to save battery. GetLastKnownLocation will almost always return null. If you want an assured non-null response, use requestLocationUpdates or requestSingleLocation. Both of those are asynchronous though, so they will call a callback when a location is found (actually figuring out a location can take from a few seconds to a minute or two, depending on the type of location provider, atmospheric conditions, line of sight issues, etc. If using GPS and inside it could actually never occur.)

Android LocationManager, rough data and battery consumption

I need just rough data about a location on Android, so when getting it the main consideration is to keep the battery power. I consider this code:
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 10 * 60 * 1000, 1000, this);
Is it right strategy? Or is it better to check, something like every 10 minutes for new location and disable listener, which seems closer to code proposed on Google's site, though less logical to me?

Instead of mentioning provider name use criteria to get get provider. And, use criteria to set your requirement.
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
final String bestProvider = manager.getBestProvider(criteria, true);
And then finally,
locationManager.requestLocationUpdates(bestProvider, 0,1000, this);
Alternatively you can request for single location update or disable listener as soon as you done with task

Wait onLocationChanged(Location location)

I need to get current location, and after that - do next code. How can i wait while this method has finished? onLocationChanged is called automatically that why i have problem. Do someone has any ideas how to do itmore correct?
I make it very stupid, in OnLocationChanged() i call onResume(), but it is so bad idea.
#Override
public void onLocationChanged(Location location) {
final Location loc = location;
Log.d("myLogs", "OnChange2");
Log.d("myLogs", "2" + loc.getLatitude() + "," + loc.getLongitude());
myLat = loc.getLatitude();
myLong = location.getLongitude();
onResume();
}

You might want to use AsyncTask for that. See Android find GPS location once, show loading dialog for the answers. Basically in onPreExecute you can start dialog( it starts before the doInBackground is called). It means you are waiting till the time you can location and showing the dialog. Then in doInBackground you can get the location. After that finishes onPostExecute is called. You can stop is from inside onPostExecute. You can check if the location is not null and then call some other function from inside onPostExecute also if you want.
This might be one way. You can learn a basic example from AsyncTask Android example . You can also start by reading the documentation here and read How to Get GPS Location Using AsyncTask? .
Some other similar helpful questions:
Wait for current location - GPS - Android Dev
getting location instantly in android
Hope this helps.

I realize the OP has accepted the above answer but I have a feeling the OP wanted a more simple answer.
I am assuming the OP has an android application with an Activity. I declared mine like this:
public class HelloAndroidActivity extends Activity implements LocationListener {
The OP was confused as to how the lifecycle methods worked and when work should be done. My Resume and Pause methods would look like this:
#Override
protected void onPause() {
((LocationManager)getSystemService(Context.LOCATION_SERVICE)).removeUpdates(this);
super.onPause();
}
#Override
protected void onResume() {
((LocationManager)getSystemService(Context.LOCATION_SERVICE)).requestLocationUpdates(LocationManager.GPS_PROVIDER, 5 * 1000, 1, this);
super.onResume();
}
Notice that my onResume asks that I be notified when there are location updates and the onPause method asks that I no longer be notified. You should be careful to not ask for updates at a time interval smaller then you really need or you will drain your battery.
Since the activity implements LocationListener my onLocationChanged method looks like this:
#Override
public void onLocationChanged(Location location) {
// Update the location fields
((EditText)findViewById(R.id.latField)).setText(Double.toString(location.getLatitude()));
((EditText)findViewById(R.id.longField)).setText(Double.toString(location.getLongitude()));
}
This simply takes the new location and updates some text EditText fields that I have in my activity. The only other thing I needed to do was to add the GPS permission to my manifest:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
So if I were asking how to start out using the location manager and the location service this would be how I would begin. I'm not trying to take anything away from the accepted answer, I just think there was a fundamental misunderstanding about what to do in onResume and in the onLocationMethodChanged methods.

Getting Coordinates From Button Press Not Working

I am pretty new to Android Development, and I've tried to make a method in my Android Application, where you press the button and get coordinates (Longitude and Latitude). But the program stops working on the emulator when I press the button.
I am probably just doing something wrong here. Looking through the Callstack didn't help me. It was simply too cluttered with...a lot of useless information.
How do I fix this?
public void onLocateByGMapButtonClick() {
LocationManager mloc = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
List<String> providers = mloc.getAllProviders();
Location loc = new Location(providers.get(0));
double loTude = loc.getLongitude();
double laTude = loc.getLatitude();
String newCoords = loTude + "," + laTude;
location.setText(newCoords);
Toast.makeText(this.getBaseContext(),"Location have been updated!",5);
}

The reason you application is crashing is probably because you are receiving a null pointer exception.
You have to understand that a GPS fix is not an immediate process, it might take time and in this time you don't have a location to work on unless you use the getLaskKnownLocation method (which maybe return null as well).
So what you need to to is or use:
Location loc = lm.getLastKnownLocation(provider);
or implement a LocationListener that will fire as soon as a new location update arrives.
Tutorial: http://www.vogella.com/articles/AndroidLocationAPI/article.html

How does really work the requestLocationUpdates of LocationManager in Android?

Working with the Location Manager in Android, nce you first call the requestLocationUpdates, the value you pass it to select the refresh time can be changed?
Let me explain. Here we have what I'm doing (and works perfect):
(...)
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, GPSrefresh, GPSminDistance, locationListener);
(...)
public void onLocationChanged(Location location) {
// Do what you want to do
}
If, after some time, I change the value of GPSrefresh, Is it going to affect to the locationUpdates? Is it always checking the value of GPSrefresh or it just did it the first time it was called?
Thank you very much.

you are passing values to a method requestLocationUpdates of LocationManager calss and then updateing that value..so it will not affect the previous method call..
Like,
String tmp="Mango";
Fruits.add(tmp);
tmp="Apple";
in above only Mango will be added..to add Apple you will have to call Fruits.add(tmp) again,
Same way..IF you cange value of GPSRefresh you will need to call the method requestLocationUpdates again with the new updated parameters.