Using Current Location from Location Manager in a Google Maps openURL?

Question

Been looking into this for a while today however I can't seem to get my head around how to get the users current location into a Google Maps URL to open the Google Maps app with directions populated.

I've taken this code from another tutorial and added it into my app. I need to get the "start" lat/lng from the below into my IBAction to open the Google Maps app.

- (void)locationUpdate:(CLLocation *)location {
    // Lat/Lng of user (Needs to be sent to IBAction for btnDirections)
    CLLocationCoordinate2D start = { location.coordinate.latitude, location.coordinate.longitude };
}

The below is my IBAction for my "Get Directions" button.

- (IBAction) onButtonClick:(id) sender {
    if(sender == btnDirections) {
        CLLocationCoordinate2D destination = { 52.48306771095311, -1.8935537338256836 };            
        NSString *googleMapsURLString = [NSString stringWithFormat:@"http://maps.google.com/?saddr=%1.6f,%1.6f&daddr=%1.6f,%1.6f",
                                         newLocation.coordinate.latitude, newLocation.coordinate.longitude, destination.latitude, destination.longitude];
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:googleMapsURLString]];      
    }
}

I have done this previously in another app, however that view included a map showing the user location which allowed me to get the lat/lng easily.

Thanks in advance.

Answer 1

In my code, I have an URL of the format :

http://maps.google.com/maps?daddr=%f,%f&saddr=%f,%f

(So that's 'maps' added from yours).

Other than that, you can setup your location request to stop after a set precision, did you setup precise enough for your purpose?

Oh, last note, getting current location might not work in simulator.

Answer 2

You need to make the user's current location available to the onButtonClick: method. You are creating the start structure on each location update, but you are never making it available outside of that method.