How to integrate a map in iPhone app

I followed the this tutorial to integrate map in my iPhone app.

Here is my projectnamecontroller.m file

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.

- (void)viewDidLoad {
     NSString *url = @"http://maps.google.com/maps?q=London";
     NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
  开发者_Go百科  [webView loadRequest:request];
    [super viewDidLoad];
}

At the end the map did not show up the iPhone simulator screen. Any idea?

If you want google map integration pls refer this previous SO question

Integrating google map in iphone app

Or you can go through MKMapView by following this tutorial