iOS GPS Battery drain, how to make it less drain? - ios

Question

My service needs gps. I actually implemented a service, which turns the gps on, checks if the location is valid, and then goes to sleep for some time. (Starting with 5 seconds, and if no movement is detected, it can sleep up to a minute)
After that, I start the gps again, and get a new location.
But the battery drain is still high! Ive used locMgr.distanceFilter = 10.0f and desiredAccurady = NearestTenMeters.
How do I minimize battery drain more?

Answer 1

This is how I handle it. After I grab the location I store it in a NSDictionary. Then if I need to location again I return the NSDictionary instead of turning the GPS back on. After 2 minutes I reset the NSDictionary (you can adjust the time to what best suites you app). Then the next time I need the location after the NSDictionary was reset I grab a new location from the GPS.
- (NSDictionary *) getCurrentLocation {
if (self.currentLocationDict == nil) {
self.currentLocationDict = [[NSMutableDictionary alloc] init];
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
locationManager.distanceFilter = kCLDistanceFilterNone;
[locationManager startUpdatingLocation];
CLLocation *myLocation = [locationManager location];
[self.currentLocationDict setObject:[NSString stringWithFormat:#"%f", myLocation.coordinate.latitude] forKey:#"lat"];
[self.currentLocationDict setObject:[NSString stringWithFormat:#"%f", myLocation.coordinate.longitude] forKey:#"lng"];
[locationManager stopUpdatingLocation];
[locationManager release];
//Below timer is to help save battery by only getting new location only after 2 min has passed from the last time a new position was taken. Last location is saved in currentLocationDict
[NSTimer scheduledTimerWithTimeInterval:120 target:self selector:#selector(resetCurrentLocation) userInfo:nil repeats:NO];
}
return self.currentLocationDict;
}
- (void) resetCurrentLocation {
NSLog(#"reset");
[currentLocationDict release];
self.currentLocationDict = nil;
}