Question

I have this code:

[NSURLConnection sendAsynchronousRequest:urlRequest queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
 {         
     NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

     if ( error != nil )
     {
         // Display a message to the screen.
         UIAlertView *message = [[UIAlertView alloc] initWithTitle:@"There was a server error getting your business plan. We use a remote server to backup your work." 
                    message:@"Please make sure your phone is connected to the Internet. If the problem persists, please let us know about this." 
                delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];

         [message show];

but it executes when a NSUrlConnection returns from the server. It creates a crash on rare occasions. Is it possible? It seems like such a harmless piece of code.

Thanks!

Answer 1

Is the NSURLConnection returning a result on some odd thread? I don’t know, but I suspect that UIAlertView is only meant to work on the UI thread, since it starts with UI.

 (dispatch_async(dispatch_get_main_queue(), ^{ 
    UIAlertView *message = [[UIAlertView alloc] initWithTitle:@"There was a server error getting your business plan. We use a remote server to backup your work." 
                message:@"Please make sure your phone is connected to the Internet. If the problem persists, please let us know about this." 
            delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];

     [message show];
 });)

Sorry, haven’t compiled this, there’s probably a typo in there somewhere.