Access to a class property dependent on asyncronous content - ios

Question

The goal I want to achieve:
I want to display the user address in a view. The view is taken care of by a view controller . This VC is using the GeoAPI to get access to the user location. The GeoAPI is wrapped around the LocationManager-Class which in turn is taking care of all the locationmanager stuff. In this location Manager class I would like to reversegeocode as mentioned above.
The geoAPI has some convenience methods that can be used to get the information I want.
GeoAPI:
#import <Foundation/Foundation.h>
#interface MFGeoAPI : NSObject
#property (nonatomic, strong) NSDictionary *userLocationInfoDict;
+ (MFGeoAPI *)sharedInstance;
- (CLLocation *)getCurrentUserLocation;
#end
#interface MFGeoAPI () {
LocationManager *locationManager;
MotionManager *motionManager;
}
#end
#implementation MFGeoAPI
+(MFGeoAPI *)sharedInstance {
static MFGeoAPI *_sharedInstance = nil;
static dispatch_once_t oncePredicate;
dispatch_once(&oncePredicate, ^{
_sharedInstance = [[MFGeoAPI alloc] init];
});
return _sharedInstance;
}
- (id)init {
if (self = [super init]) {
locationManager = [[LocationManager alloc] initLocationManager];
motionManager = [[MotionManager alloc] initMotionManager];
}
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(getUserLocationInformation:) name:#"UserLocationInfo" object:nil];
return self;
}
- (CLLocation *)getCurrentUserLocation {
return [locationManager getCurrentUserLocation];
}
- (void)getUserLocationInformation:(NSNotification *)notification {
NSLog(#"OK");
self.userLocationInfoDict = [[NSDictionary alloc] initWithDictionary:notification.userInfo];
}
#end
Now.. due to the fact of the async character of the reverse geocode function I won't be sure when the dictionary with the user address will be available.
The Location Manager class contains the following:
Location Manager:
#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>
#interface LocationManager : NSObject <CLLocationManagerDelegate>
#property (nonatomic, strong) CLLocationManager *locationManager;
#property (nonatomic, strong) CLLocation *userLocation;
#property (nonatomic, strong) NSDictionary *userLocDict;
- (id)initLocationManager;
- (CLLocation *)getCurrentUserLocation;
#end
#import "LocationManager.h"
#implementation LocationManager
- (id)initLocationManager {
if (self = [super init]) {
if (self.locationManager == nil) {
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
if (![self.locationManager locationServicesEnabled]) {
UIAlertView *servicesDisabledAlert = [[UIAlertView alloc] initWithTitle:#"Location Services Disabled" message:#"You currently have all location services for this device disabled. If you proceed, you will be asked to confirm whether location services should be reenabled." delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil];
[servicesDisabledAlert show];
}
}
[self startUpdatingLocation];
[self startFetchingCurrentUserLocationInformation];
}
return self;
}
- (void)startUpdatingLocation {
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
self.locationManager.headingFilter = kCLHeadingFilterNone;
[self.locationManager startUpdatingHeading];
[self.locationManager startUpdatingLocation];
self.userLocation = self.locationManager.location;
}
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
NSLog(#"FAILED");
}
- (CLLocation *)getCurrentUserLocation {
return self.userLocation;
}
- (void)startFetchingCurrentUserLocationInformation {
[self delayedReverseGeocodeLocation];
}
- (void)delayedReverseGeocodeLocation {
[NSObject cancelPreviousPerformRequestsWithTarget:self];
[self reverseGeocodeLocation];
}
- (void)reverseGeocodeLocation {
CLGeocoder *geocoder = [[CLGeocoder alloc] init];
[geocoder reverseGeocodeLocation:self.userLocation completionHandler:^(NSArray *placemarks, NSError *error) {
NSDictionary *dict = [[placemarks firstObject] addressDictionary];
if (placemarks.count > 0) {
NSDictionary *info = [NSDictionary dictionaryWithObject:dict forKey:#"transferDict"];
[[NSNotificationCenter defaultCenter] postNotificationName:#"UserLocationInfo" object:self userInfo:info];
}
}];
}
In the view Controller I would like to get access to the userLocation Information Dictionary that I am passing through the API
View Controller
- (id)init {
if (self = [super init]) {
self.userLocation = [[MFGeoAPI sharedInstance] getCurrentUserLocation];
NSLog(#"%#", [[MFGeoAPI sharedInstance].userLocationInfoDict description]);
}
return self;
}
But the userlocationInfoDict is empty. I guess this is due to the fact that my function-call "startFetchingCurrentUserLocationInformation" is returning before the async block returns the values I need. Then I thought by taking care of this through NSNotificationCenter I will be informed when the data is available. But now I am stuck:
What do I have to do to get access to the userLocationInformation passed by the GeoAPI to do it in time when the data has arrived?
Any help appreciated!
Thank you
Sebastian