Question

Assuming that I actually have an internet connection, I’ use this code to know if the device is connected via WiFi or not :

+ (BOOL)hasWiFiConnection {

    Reachability *reachability = [Reachability reachabilityForInternetConnection];
    [reachability startNotifier];

    NetworkStatus status = [reachability currentReachabilityStatus];

    if (status == ReachableViaWiFi) {

        return YES;

    } else {

        return NO;
    }
}

Is that code fast to run?

I’m using it when generating URLs for pictures (so that I know if I load high or low resolution pictures). Those pictures are displayed in a list view (3 per line). When the I scroll the list the function is called several times per second. Is that efficient?

Answer 1

if u dont want to use reachability Class use the following code.

        @interface CMLNetworkManager : NSObject
        +(CMLNetworkManager *) sharedInstance;

       -(BOOL) hasConnectivity;
          @end

Implementation

         @implementation CMLNetworkManager

         +(CMLNetworkManager *) sharedInstance {
     static CMLNetworkManager *_instance = nil;
@synchronized(self) {
    if(_instance == nil) {
        _instance = [[super alloc] init];
    }
}
return _instance;
 }

   -(BOOL) hasConnectivity {
struct sockaddr_in zeroAddress;
bzero(&zeroAddress, sizeof(zeroAddress));
zeroAddress.sin_len = sizeof(zeroAddress);
zeroAddress.sin_family = AF_INET;

SCNetworkReachabilityRef reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (const struct sockaddr*)&zeroAddress);
if(reachability != NULL) {
    //NetworkStatus retVal = NotReachable;
    SCNetworkReachabilityFlags flags;
    if (SCNetworkReachabilityGetFlags(reachability, &flags)) {
        if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
        {
            // if target host is not reachable
            return NO;
        }

        if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
        {
            // if target host is reachable and no connection is required
            //  then we'll assume (for now) that your on Wi-Fi
            return YES;
        }


        if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0) ||
             (flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
        {
            // ... and the connection is on-demand (or on-traffic) if the
            //     calling application is using the CFSocketStream or higher APIs

            if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
            {
                // ... and no [user] intervention is needed
                return YES;
            }
        }

        if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
        {
            // ... but WWAN connections are OK if the calling application
            //     is using the CFNetwork (CFSocketStream?) APIs.
            return YES;
        }
    }
}

return NO;
  }
  @end

use the bool method with class shared Instance were ever you want