diego.org Posts

I was recently adding some code to check for the availability of the network, so I can display an error to the user if unavailable.

I looked at the SeismicXML application and borrowed the following code:

// Use the SystemConfiguration framework to determine if the host that provides
// the RSS feed is available.
– (BOOL)isDataSourceAvailable
{
static BOOL checkNetwork = YES;
if (checkNetwork) {
// Since checking the reachability of a host can be expensive,
// cache the result and perform the reachability check once.
checkNetwork = NO;

Boolean success;
const char *host_name = “earthquake.usgs.gov”;
//const char *host_name = “localhost”;

SCNetworkReachabilityRef reachability =
SCNetworkReachabilityCreateWithName(NULL, host_name);
SCNetworkReachabilityFlags flags;
success = SCNetworkReachabilityGetFlags(reachability, &flags);
_isDataSourceAvailable = success &&
(flags & kSCNetworkFlagsReachable) &&
!(flags & kSCNetworkFlagsConnectionRequired);
CFRelease(reachability);
}
return _isDataSourceAvailable;
}

I wouldn’t compile unless I added the following import:

#import

After adding this I still go 2 more errors, but these were a bit more cryptic.

 Undefined symbols:
"_SCNetworkReachabilityCreateWithName", referenced from:
-[TheElementsAppDelegate isDataSourceAvailable] in TheElementsAppDelegate.o
"_SCNetworkReachabilityGetFlags", referenced from:
-[TheElementsAppDelegate isDataSourceAvailable] in TheElementsAppDelegate.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

After some digging around I realized that I was missing the SystemConfiguration.framework framework.

So here is what I did to add it.
1. I right click on “Frameworks” and choose: Add < Existing Framework

2. Browsed to the file: /System/Library/Frameworks/SystemConfiguration.framework

3. Rebuilt the project and my error was gone.

I recently spent about 2 hours trying to get my Distribution Provisioning Profile to show up. I followed the instructions and did everything, but still it would not show up.

Then I came across this thread: http://www.v2ex.com/2008/10/22/distribution-provisioning-profile-not-showing-up/

The first suggestion was to create a new project. I created a new project and my Distribution Provisioning profile appeared in it. Then I went back to my main project and it appeared there too. Problem solved!

Here some sample code showing you how to open a link in Safari when clicked on in your UIWebView. The method shouldStartLoadWithRequest is a delegate method that is called when a link is clicked on. You can override the method and tell it to open in Safari.

– (BOOL)webView:(UIWebView *)webView
shouldStartLoadWithRequest:(NSURLRequest *)request
navigationType:(UIWebViewNavigationType)navigationType; {

NSURL *requestURL = [ [ request URL ] retain ];
// Check to see what protocol/scheme the requested URL is.
if ( ( [ [ requestURL scheme ] isEqualToString: @”http” ]
|| [ [ requestURL scheme ] isEqualToString: @”https” ] )
&& ( navigationType == UIWebViewNavigationTypeLinkClicked ) ) {
return ![ [ UIApplication sharedApplication ] openURL: [ requestURL autorelease ] ];
}
// Auto release
[ requestURL release ];
// If request url is something other than http or https it will open
// in UIWebView. You could also check for the other following
// protocols: tel, mailto and sms
return YES;
}
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