Append Google Maps URL with Current Location - objective-c

Question

I am trying to compose an email with a Google Maps link using Core Location and MessageUI. Presently my code produces this string: https://maps.google.com?saddr=Current+Location&daddr=0.000000,0.000000.
I would like to append the device's longitude and latitude with the URL.
Here is my implementation:
#import "ViewController.h"
#interface ViewController () <CLLocationManagerDelegate>
#end
#implementation ViewController{
NSString *currentLongitude;
NSString *currentLatitude;
NSString *googleMapsURL;
CLLocationManager *locationManager_;
}
- (void)viewDidLoad {
[super viewDidLoad];
locationManager_ = [[CLLocationManager alloc] init];
locationManager_.delegate = self;
locationManager_.distanceFilter = kCLDistanceFilterNone;
locationManager_.desiredAccuracy = kCLLocationAccuracyBest;
[locationManager_ requestAlwaysAuthorization];
[locationManager_ startUpdatingLocation];
}
- (IBAction)composeMailButton:(id)sender {
NSString *bodyHeader = #"Here are you directions:";
NSString *mailBody = [NSString stringWithFormat:#"%#\n%#", bodyHeader, googleMapsURL];
MFMailComposeViewController *emailComposer = [[MFMailComposeViewController alloc] init];
[emailComposer setSubject:#"Google Maps Directions"];
[emailComposer setMessageBody:mailBody isHTML:NO];
[emailComposer setToRecipients:#[#"castro.michael87#gmail.com"]];
[emailComposer setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[self presentViewController:emailComposer animated:YES completion:nil];
}
-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
CLLocation *newLocation = [locations lastObject];
NSString *googleMapsURL = [[NSString alloc] initWithFormat:#"https://maps.google.com?saddr=Current+Location&daddr=%1.6f,%1.6f",newLocation.coordinate.latitude, newLocation.coordinate.longitude];
}
I am guessing that I have not correctly implemented the locationManager. Any input is very much appreciated!

Answer 1

First, you need to make use that you added the NSLocationWhenInUseUsageDescription and NSLocationAlwaysUsageDescription in your info.plist file.
Second, your viewController need to implement the <CLLocationManagerDelegate>
#interface ViewController ()<CLLocationManagerDelegate>
Third, setup your locationManager in your viewDidLoad method.
locationManager_ = [[CLLocationManager alloc] init];
locationManager_.delegate = self;
locationManager_.distanceFilter = kCLDistanceFilterNone;
locationManager_.desiredAccuracy = kCLLocationAccuracyBest;
[locationManager_ requestAlwaysAuthorization];
[locationManager_ startUpdatingLocation];
Fourth, implement the -(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations method:
-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
CLLocation *newLocation = [locations lastObject];
NSString *googleMapsURL = [[NSString alloc] initWithFormat:#"https://maps.google.com?saddr=Current+Location&daddr=%1.6f,%1.6f",newLocation.coordinate.latitude, newLocation.coordinate.longitude];
NSLog(#"%#", googleMapsURL);
}
Finally, if you test in simulator, you need to simulate a location:
Code Snippet: https://gist.github.com/ziyang0621/b1be760596da54873f81