How to get information printed in Xcode's console onto screen? - ios

Question

I started using Xcode a couple days ago and I'm completely lost. I'm trying to get a GPS locator app running found here.
Basically, the app prints any updated GPS information using NSLog, which as far as my understanding goes, prints to Xcode's console. However, I'd like to get this info printed onto the screen.
Here's the code from CFAStartViewController.m that successfully prints to the screen:
-(void)viewDidAppear:(BOOL)animated{
CFAAppDelegate *appDelegate=(CFAAppDelegate *)[UIApplication sharedApplication].delegate;
CLLocation *currentLocation=appDelegate.locationManager.location;
self.labelLocationInformation.text=[NSString stringWithFormat:#"latitude: %+.6f\nlongitude: %+.6f\naccuracy: %f",
currentLocation.coordinate.latitude,
currentLocation.coordinate.longitude,
currentLocation.horizontalAccuracy];
}
And here's the code in CFAAppDelegate.m that successfully prints to the console:
-(void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{
NSDate* eventDate = newLocation.timestamp;
NSTimeInterval howRecent = [eventDate timeIntervalSinceNow];
if (abs(howRecent) < 15.0)
{
//Location timestamp is within the last 15.0 seconds, let's use it!
if(newLocation.horizontalAccuracy<35.0){
//Location seems pretty accurate, let's use it!
NSLog(#"latitude %+.6f, longitude %+.6f\n",
newLocation.coordinate.latitude,
newLocation.coordinate.longitude);
NSLog(#"Horizontal Accuracy:%f", newLocation.horizontalAccuracy);
//Optional: turn off location services once we've gotten a good location
//[manager stopUpdatingLocation];
}
}
}
I tried changing the calls to NSLog to self.labelLocationInformation.text, with a similar format to that of CFAStartViewController, but it doesn't seem to do anything. I've read through the basic tutorials of Xcode, but I feel there's some knowledge lacking (obviously) on what to do overall.
If the best you could do is post a link that helps me solve this problem, that would be great.

Answer 1

I think the problem is due to scope - the didUpdateToLocation: method is sent to the location manager delegate, ie your app delegate, which doesn't have the label in scope. Try changing your delegate for the location manager to be your CFAStartViewController, and move the associated location manager delegate code from App Delegate to CFAStartViewController. Then the label will be in scope when didUpdateToLocation: is called.

Answer 2

Based on your clarifying response to my comment.... If you want the data from CFAAppDelegate to be presented in your CFAStartViewController then you need to send that data to CFAStartViewController (or CFAStartViewController needs to get it). To send it 1) provide a storyboard id for CFAStartViewController such as "CFAVC". 2) define or expose properties in CFAStartViewController to contain your data. 3) instantiate CFAStartViewController via the following from within CFAAppDelegate:
// in CFAStartViewController.h define property such as:
#property (strong, nonatomic) CLLocation *incomingLocation;
// in CFAAppDelegate.m
// get a pointer to your VC
CFAStartViewController *destinationVC = [self.storyboard instantiateViewControllerWithIdentifier:#"CFAVC"];
// set properties on VC
destinationVC.incomingLocation = newLocation;
// show CFAStartViewController (or use whatever method you are currently using)
[self.navigationController pushViewController:destinationVC animated:YES];