如何在 MKMapView 上绘制我当前位置到所需位置之间的路线？

Question

I want to show a route between my current location and desired location. I am able to do this but when the source point and destination point so far then it will not show a route and gave the memory warning. Can you suggest any sample code or any way to do this?

Answer 1

Following Code for the draw path between the current location to desire location

- (void)viewDidLoad {
    [super viewDidLoad];

    mapView = [[[MapView alloc] initWithFrame:
                         CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)] autorelease];

    [self.view addSubview:mapView];
    [self performSelector:@selector(LoadMaps) withObject:self afterDelay:1.0];
}

-(void)LoadMaps{
    MapWithRoutesAppDelegate *app = (MapWithRoutesAppDelegate *)[[UIApplication sharedApplication]delegate];
    CLLocation *location = app.userlocation;
    // Configure the new event with information from the location
    CLLocationCoordinate2D coordinate = [location coordinate];

    NSString *latitude = [NSString stringWithFormat:@"%f", coordinate.latitude];
    NSString *longitude = [NSString stringWithFormat:@"%f", coordinate.longitude];

    NSLog(@"dLatitude : %@", latitude);
    NSLog(@"dLongitude : %@",longitude);


    Place* home = [[[Place alloc] init] autorelease];
    home.name = @"Home";
    home.description = @"Sweet home";
    home.latitude = coordinate.latitude;
    home.longitude = coordinate.longitude;

    Place* office = [[[Place alloc] init] autorelease];
    office.name = @"Office";
    office.description = @"Bad office";
    office.latitude = 23.329404;
    office.longitude = 72.0039299;

    [mapView showRouteFrom:home to:office];
    NSLog(@"latitide:%.7f, longitude: %.7f ", coordinate.latitude, coordinate.longitude);
}

In Appdelegate Method contain

#pragma mark- CLLocationManager delegate
- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation{
    MapWithRoutesAppDelegate *app = (MapWithRoutesAppDelegate*)[[UIApplication sharedApplication] delegate];
    app.userlocation = newLocation;
    NSLog(@"latitide:%.7f, longitude: %.7f ", app.userlocation.coordinate.latitude, app.userlocation.coordinate.longitude);
}

You can download the complete source code from here.

May this help lot.