在iOS7中的MKMapView上显示MKRoute

Question

I'm using MKDirectionsRequest to find a MKRoute between two points. The response will be displayed on the MKMapView using this code:

MKDirections *directions = [[MKDirections alloc] initWithRequest:request];
    [directions calculateDirectionsWithCompletionHandler:^(MKDirectionsResponse *response, NSError *error)
     {
         if (error)
         {
             NSLog(@"Error : %@", error);
         }
         else
         {
             [_mapView removeOverlays:_mapView.overlays];
             for (MKRoute *route in response.routes)
             {
                 [_mapView insertOverlay:route.polyline atIndex:0 level:MKOverlayLevelAboveRoads];
             }
         }
     }];

My question is, if there is a proper way to update the MKRoute if the user is moving. Atm I'm using

- (void)mapView:(MKMapView *)aMapView didUpdateUserLocation:(MKUserLocation *)aUserLocation

to recognize movement and in this method I'm removing the MKRoute overlay and calculating and adding the new with the new user location. I'm wondering if there is a way to compute the route only one time and updating the overlay programmatically?

Edit: I found this https://developer.apple.com/library/ios/documentation/MapKit/Reference/MKRouteStep_class/Reference/Reference.html#//apple_ref/occ/cl/MKRouteStep in Apples Dev Docs. I guess i have to do something like

for (MKRoute *route in response.routes)
{
   for (MKRouteStep *step in route.steps) 
   {
      [_mapView insertOverlay:step.polyline atIndex:0 level:MKOverlayLevelAboveRoads];
   }
}

but how can i recognize which steps are behind the actual user location?

Edit: An other option could be to use a timer which triggers the event (removing the old overlay and adding the new one). What do you think?

[NSTimer scheduledTimerWithTimeInterval:15 target:self selector:@selector(addRouteOverlay) userInfo:nil repeats:YES];

Answer 1

Below link contains the sample code to show directions on a MKMapView, we only need to pass latitude and longitude values in it.

https://github.com/kadirpekel/MapWithRoutes

Answer 2

I have a nice solution to do this kind of work.

Simply, get destination location like below with lat (like -34.059811) and long (like 150.769238).

CLLocation  *destinationLocation=[[CLLocation alloc] initWithLatitude:-34.059811 longitude:150.769238];

and pass this lat long in below url string,you can directly pass this lat long in string,

NSString* strLink = [NSString stringWithFormat:@"http://maps.google.com/maps?saddr=Current+Location&daddr=%f,%f",destinationLocation.latitude,destinationLocation.longitude];

Now make a url,

NSURL *url = [NSURL URLWithString: [strLink stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding]];

Open this url in browser or UIWebView and refresh that page with timer and see the magic,route will automatically update according to current location and destination location,you don't need to update current location every time.

Thanks.