iphone gps system

[expertadvisor]

Guys-
Is the gps on by default? if we are creating an app that interacts with the gps, is the gps always on or how do we make sure its always ON automatically??

Many TIA

[Dutch]

Originally Posted by expertadvisor

Guys-
Is the gps on by default? if we are creating an app that interacts with the gps, is the gps always on or how do we make sure its always ON automatically??

Many TIA

define "ON"... In other words, when your app loads and you want to use the GPS, you need to request permission from the user using something like this

	locmanager = [[CLLocationManager alloc] init]; 
	[locmanager setDelegate:self]; 
	[locmanager setDesiredAccuracy:kCLLocationAccuracyBest];
	[locmanager startUpdatingLocation];

Once you call startUpdatingLocation, the user will be asked whether or not to allow your app access to GPS data.

If they click NO you get an error

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error { 
	NSLog(@"Error Encountered");
}

if they click YES, you must handle it in the following code:

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{ 

	if (wasFound) return; 
	
	numberOfLocationUpdates++;
	
	NSDate* newLocationEventTime = newLocation.timestamp;
	NSTimeInterval howRecentNewLocation = [newLocationEventTime timeIntervalSinceNow];
	
	// filter cached and previous locations
	if ((!currentLocation || currentLocation.horizontalAccuracy >= newLocation.horizontalAccuracy) && (howRecentNewLocation < -0.0 && howRecentNewLocation > -10.0))  {
		if (currentLocation) {
			[currentLocation release];
		}
		currentLocation = [newLocation retain];
	}
	
	if (currentLocation  || numberOfLocationUpdates >= 15) {
		[locmanager stopUpdatingLocation];

		numberOfLocationUpdates = 0;
		//Use newLocation here
	}

}

[expertadvisor]

Wow, thanks.
generically, trying to figure out if I can auto launch an app to run that uses gps all the time, one that people can not turn off or disable without a password.

[Dutch]

Originally Posted by expertadvisor

Wow, thanks.
generically, trying to figure out if I can auto launch an app to run that uses gps all the time, one that people can not turn off or disable without a password.

That would be a negative. When it comes to permissions and such, your app is 'the intruder' and only it is subject to limitations on the locationManager. If the user wants to turn it off, all they need to do is press the home button and close your app.