android - Why is FusedLocationApi.getLastLocation null

Question

I am trying to get location by using FusedLocationApi.getLastLocation and I've got the location permissions in the manifest file:

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

However, I am getting null when I request the location from the system. I was just testing turning off and on location services so it may be related to that (of course, it's ON when I'm trying this). But even after returning null, I'm waiting for onLocationChanged to be called and it's never called. I've also seen a similar question here: FusedLocationApi.getLastLocation always null

Here is my code:

 protected LocationRequest createLocationRequest() {
    LocationRequest mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(120000);
    mLocationRequest.setFastestInterval(30000);
    mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
    return mLocationRequest;
}

protected GoogleApiClient getLocationApiClient(){
    return new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();
}

LocationRequest locationRequest = createLocationRequest(); 

@Override
public void onLocationChanged(Location location) {
    App.setLocation(location); // NEVER CALLED
}

@Override
public void onConnected(Bundle bundle) {
    App.setLocation(LocationServices.FusedLocationApi.getLastLocation(locationApiClient)); //RETURNS NULL
    LocationRequest locationRequest = createLocationRequest();
    LocationServices.FusedLocationApi.requestLocationUpdates(locationApiClient, locationRequest, this);
}

And on onCreate of my app:

locationApiClient = getLocationApiClient();
locationApiClient.connect();

Where this is my application object. Why am I getting null (yes, I do know it may be null in some rare circumstances as stated in the documents, but I'm ALWAYS getting this, not rarely) and still not getting location updates thereafter? It's a real device (Samsung Galaxy S3) without a SIM card, if it helps.

Answer 1

The fused location provider will only maintain background location if at least one client is connected to it. Now just turning on the location service will not guarantee storing the last known location.

Once the first client connects, it will immediately try to get a location. If your activity is the first client to connect and getLastLocation() is invoked right away in onConnected(), that might not be enough time for the first location to arrive..

Then you are setting mLocationRequest.setFastestInterval(30000); which basically means 30 seconds. so at least 30 seconds after and generally according to your setting preferred time is 120 secs, isn't it a very long time if there is no stored last known location at all? plus you are setting battery balanced priority, which will make you waiting longer time.

mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);

I suggest you to launch Maps app first, so that there is at least some confirmed location and then test your app.