最近在写个app，要调地图来展示一个地点，于是就有了三种选择：ios5之前的, 装了gmap的ios6和没装gmap的，在网上转了转，拼出来下面一段代码：

if ([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@“comgooglemaps://"]]) { // iOS 6 with google map app installed NSString *loc_path = [[NSString alloc] initWithFormat: @“comgooglemaps://?center=%f,%f”, lat, lng]; NSURL *loc_url = [NSURL URLWithString:loc_path]; [[UIApplication sharedApplication] openURL:loc_url]; } else { // Check whether it is iOS 6 Class mapItemClass = [MKMapItem class]; if (mapItemClass && [mapItemClass respondsToSelector:@selector(openMapsWithItems:launchOptions:)]) { CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(lat, lng); MKPlacemark *placemark = [[MKPlacemark alloc] initWithCoordinate:coordinate addressDictionary:nil]; MKMapItem *mapItem = [[MKMapItem alloc] initWithPlacemark:placemark]; [mapItem setName:venue_name];

            [mapItem openInMapsWithLaunchOptions:nil];
        } else {
            // Early than iOS 6
            NSString *loc_path = [[NSString alloc] initWithFormat: @"http://maps.google.com/maps?ll=%f,%f", lat, lng];
            NSURL *loc_url = [NSURL URLWithString:loc_path];
            [[UIApplication sharedApplication] openURL:loc_url];
        }
    }

逻辑很简单，首先判断是否可以打开gmap app的[URL schema](https://developers.google.com/maps/docum entation/ios/urlscheme)，如果不行则试着创建iOS 6新加入的MKMapItem，如果不能打开，则就是老的iOS了。因为只需要打开系统内建的map程序，所以就这样啦。

PS: MKMapItem那段程序是从网上找到的，嗯。