Rechability connection to internet - ios

Question

I want to execute some code only, and only if I am connected to the internet:
//Reachability
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];
Reachability * reach = [Reachability reachabilityWithHostname:#"www.dropbox.com"];
reach.reachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(#"Block Says Reachable");
connect = #"yes";
});
};
reach.unreachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
connect = #"no";
});
};
[reach startNotifier];
//Reachability
if (connect == #"no") {
UIAlertView *alert1 = [[UIAlertView alloc] initWithTitle:#"" message:#"There is no internet connection. Please connect to the internet. If you are already connected, there might be a problem with our server. Try again in a moment." delegate:self cancelButtonTitle:#"Dismiss" otherButtonTitles: nil];
[alert1 show];
} else if (titleSet == NULL){
UIAlertView *alert1 = [[UIAlertView alloc] initWithTitle:#"" message:#"Please select a group or create a new one" delegate:self cancelButtonTitle:#"Dismiss" otherButtonTitles: nil];
[alert1 show];
}else if (NavBar.topItem.title.length < 1){
UIAlertView *alert1 = [[UIAlertView alloc] initWithTitle:#"" message:#"Please select a group or create a new one" delegate:self cancelButtonTitle:#"Dismiss" otherButtonTitles: nil];
[alert1 show];
} else if (newmessagename.text.length < 4){
UIAlertView *alert1 = [[UIAlertView alloc] initWithTitle:#"" message:#"Please give a name to your event that is at least 4 characters long" delegate:self cancelButtonTitle:#"Dismiss" otherButtonTitles: nil];
[alert1 show];
}
It seems that the code is not executed in order. I think it is taking more time to check the Internet connection than it takes to execute the code. How can I fix this?
Please do not tell me to place the code directly in the parenthesis where connect = #"no"; is located.

Answer 1

The blocks aren't executed sequentially, they are executed asynchronously.
This means that you can't tell when the code inside the blocks is going to be called. The code using the block may finish and execute before the rest of your method (however this is unlikely, especially with Internet connections).
You should place your ifs in a method that is called at a valid time. This time is probably when you receive a response from your blocks, or, if my memory serves true, [reach startNotifier]; can notify you when there is a change in reachability status, this appears to be your reachabilityChanged: method:
-(void) reachabilityChanged:(id) parameter
{
//Query reachability and notify / cache as required.
}

Answer 2

Of course its not executed in order, the whole point of those methods is to stop the ui to freeze while you get your reachability response. Basically you set up the reachability responses and immediately ask for the result when nothing has been checked yet. What you have to really is to move it inside the brackets.
Something else that you can do is make a function with those results, and call this function in both of the blocks.
If you want to have this on the load of the viewcontroller or before you display anything else, then you either have to check for reachability before you show this controller, or add a "loading" screen.
EDIT: Something else that i dont understand is, those reachability methods seem to fire a block when they get the results, but you are registering for a notification as well. And i dont see you posting a notification for this. You are using 2 asynchronous approches here (blocks and notifications)