Comments on: iPhone Network Connectivity Test Example

By: Chris Danielson

Chris Danielson — Wed, 07 Dec 2011 15:01:40 +0000

The fix for what you are asking is to actually try and pull say http://google.com in your initial request. I hate pinging Apple or Google in my tests, but it is in fact a more complete implementation. You can find a great method that does this in the AppiRater source code located at:
https://github.com/arashpayan/appirater
- (BOOL)connectedToNetwork { // Create zero addy struct sockaddr_in zeroAddress; bzero(&zeroAddress, sizeof(zeroAddress)); zeroAddress.sin_len = sizeof(zeroAddress); zeroAddress.sin_family = AF_INET;


    // Recover reachability flags

    SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);

    SCNetworkReachabilityFlags flags;
    BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);

    CFRelease(defaultRouteReachability);
    if (!didRetrieveFlags)

    {

        NSLog(@"Error. Could not recover network reachability flags");

        return NO;

    }
    BOOL isReachable = flags & kSCNetworkFlagsReachable;

    BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;

	BOOL nonWiFi = flags & kSCNetworkReachabilityFlagsTransientConnection;
	NSURL *testURL = [NSURL URLWithString:@"http://www.apple.com/"];

	NSURLRequest *testRequest = [NSURLRequest requestWithURL:testURL  cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20.0];

	NSURLConnection *testConnection = [[NSURLConnection alloc] initWithRequest:testRequest delegate:self];

return ((isReachable && !needsConnection) || nonWiFi) ? (testConnection ? YES : NO) : NO; }

Kind Regards,
Chris

By: Hamon Raphaël

Hamon Raphaël — Mon, 05 Dec 2011 15:40:42 +0000

Hi !

It seems great, but I’ve found an issue. With some wifi hotspots, the iphone is connected to the hotspot but not logged into the hotspot system but the iphone stays “connected” to the hotspot but doesn’t have internet access. And so, this test doesn’t work for that kind of situation.

Raphaël

By: Chris Danielson

Chris Danielson — Tue, 17 May 2011 03:01:18 +0000

Brian,
Ideally, you would avoid redundantly putting this code in every page and access either a static method or an instance method on a particular object.

By: Brian

Brian — Mon, 16 May 2011 22:56:37 +0000

Should you put this on all pages that make a URL call?

By: Andrew Hoyer

Andrew Hoyer — Fri, 25 Feb 2011 19:44:13 +0000

Waleed, you need to include these at the top:

#import
#import

By: waleed

waleed — Wed, 22 Sep 2010 03:10:48 +0000

his great but its not woking for me

am getting

“_SCNetworkReachabilityGetFlags”, referenced from:
-[TestViewController connectedToNetwork] in TestViewController.o
“_SCNetworkReachabilityCreateWithAddress”, referenced from:
-[TestViewController connectedToNetwork] in TestViewController.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

By: Chris Danielson

Chris Danielson — Wed, 26 May 2010 14:44:02 +0000

Patrick,
I don’t think the SCNetworkReachability will handle enumerating through the known access points. I did a quick check here, and didn’t see anything.
Wish I could help you more on this endeavor. Good luck!
-Chris

By: patrick m lim

patrick m lim — Tue, 18 May 2010 01:42:44 +0000

Hi Chris,

I’m pretty new to iPhone app development especially Cocoa and Obj C. I have an application where I need to detect wifi access points (minimum of 2 APs). Does the SCNetworkReachability framework allow me to do that?

Thanks for clearing my doubts!

Warmest Regards
Patrick

By: Chris Danielson

Chris Danielson — Fri, 14 May 2010 17:31:31 +0000

Yes, this works for both 3G and WiFi connections.

By: Scott

Scott — Fri, 14 May 2010 17:29:07 +0000

Will your example above work for a 3g connection?