Append Google Maps URL with Current Location

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!

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