iOS Network Connection Testing

[Darkroom]

i don't have access to an iPhone for testing (only an iPod touch). i've read some forum posts claiming that the code listed below will only work with wifi, and not a cellular connection. is this true?

- (BOOL)internetConnection
	{
	//INTERNET CONNECTION TESTING
	//Add the SystemConfiguration framework 
	//#import <SystemConfiguration/SCNetworkReachability.h>
	//#import <netinet/in.h>
	
	struct sockaddr_in zeroAddress;
	bzero(&zeroAddress, sizeof(zeroAddress));
	zeroAddress.sin_len = sizeof(zeroAddress);
	zeroAddress.sin_family = AF_INET;

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

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

	if (!didRetrieveFlags)
		return 0;

	BOOL isReachable = flags & kSCNetworkFlagsReachable;
	BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
	
	return (isReachable && !needsConnection) ? YES : NO;
	}

- (IBAction)gotoAppStore
	{
	if ([self internetConnection] == YES)
		[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"itms-apps://ax.itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=kAppId"]];
		else
		{
		UIAlertView *alert = [[UIAlertView alloc]	initWithTitle:nil
									message:NSLocalizedString(SMConstNoInternetConnectionAlertMessage, nil) 
									delegate:self
									cancelButtonTitle:@"OK"
									otherButtonTitles:nil];
		[alert show];
		[alert release];
		}
	}

 

[csnplt]

There are several better options than what you are doing.

I personally just use something like this:

-(BOOL)connectedToInternet
{
	return ([NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"] encoding:NSUTF8StringEncoding error:NULL]!=NULL)?YES:NO;
}

It's not the most sophisticated, but for my particular need, it works fine.

For a more complex solution, look at Apple's Reachability sample code.

 

[PhoneyDeveloper]

Darkroom,

I'm pretty sure the code you show should work on the cell network as well as WiFi, but I'm not absolutely sure.

I am absolutely sure that it's not the best way and not the recommended way to do this. Look at the Reachability sample code. It works asynchronously, which I guess is a little less convenient for the kind of code that you show but it's probably better.

Don't do a synchronous network check because it can cause your app to crash.

 

[KoolStar]

I would do it properly and use apples reachability class that is provided on the developer site.