android Google maps : getLastLocation vs requestLocationUpdates

Question

I just need to understand this clearly, getLastLocation() method will give me the last known location and requestLocationUpdates will give me the current location every period of time.

now, i am developing a simple app to track mobile phones, which will be in cars.

my Question are :

1- how exactly getLastLocation() works, will this last known location be updated when the location change

2- which is better, using getLastLocation() to have the initial location then update the current location by using the method onLocationChanged or using requestLocationUpdates to have an up to date location every n sec ?

Answer 1

getLastLocation gives you the last location which was there in LocationClient, it can be null sometimes, say if you don't have any other application installed which uses location services, that's a rare case as most phones have Google maps or some other location dependent apps installed.

getLastLocation is only helpful, when you want location for once and your done with it, but for location updates you should use requestLocationUpdates, and using a service, your application will always get notified, when the location changes.

I hope you are using the FusedLocation Provider from play services, so you can specify how fast location updates you need, to check cases of battery drain and performance.

Also to note here when you use requestLocationUpdates then only you will get any location change updates.

Answer 2

so according to android docs getLastLocation() :-

Returns the best most recent location currently available. If a location is not available, which should happen very rarely, null will be returned. The best accuracy available while respecting the location permissions will be returned. This method provides a simplified way to get location. It is particularly well suited for applications that do not require an accurate location and that do not want to maintain extra logic for location updates.

This is the problem with getLastLocation(),that it is not accurate and it may return null if it does not have any last known location in cache.I have faced this issue many times in my application.So for getting the accurate location you should use requestLocationUpdates() but define the interval according to your need at which time interval you want the updates as a very short time span may cause more power usage.