Question

I have a method named -( void ) loadUrl:(NSString *) SearchStr.In that i assign value to the global nsstring

variable. Then i call Apple’s network reachability class methods using [self checkReach].

In that function i can able to print that nsstring variable. and again the

- (void) checkNetworkStatus:(NSNotification *)notice; metod is called.

In that function i cant able to print that nnstring varibale.
This crashes my application.

I dont know, why this global variable is not accesible in the - (void) checkNetworkStatus:(NSNotification *)notice; method?

Any helps would be greatly appreciated!

Thanks for your time.

Find the code below;-

#in the header file.
@property(nonatomic, retain) NSString* myEscapedUrlString;

#in the m file
@synthesize  myEscapedUrlString;

-( void ) loadUrl:(NSString *) SearchStr
{
  myEscapedUrlString  = SearchStr;

  NSLog(@"%@ ###########",myEscapedUrlString);

  [self checkReach];
}

-(void)checkReach
//----------------
{
  NSLog(@"%@ nnnnnnnnnnnnnnnnn",myEscapedUrlString);

  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(load_View) name: UIApplicationDidBecomeActiveNotification object:nil];

  // check for internet connection
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(checkNetworkStatus:) name:kReachabilityChangedNotification object:nil];

  internetReachable = [[Reachability reachabilityForInternetConnection] retain];
  [internetReachable startNotifier];

  // check if a pathway to a random host exists
  hostReachable = [[Reachability reachabilityWithHostName: @"www.testn.com"] retain];
  [hostReachable startNotifier];

}

- (void) checkNetworkStatus:(NSNotification *)notice;
//---------------------------------------------------
{
      NSLog(@"%@ nnnnnnnnnnnnnnnnn",myEscapedUrlString);
    NetworkStatus internetStatus = [internetReachable currentReachabilityStatus];

    NetworkStatus hostStatus = [hostReachable currentReachabilityStatus];

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:kReachabilityChangedNotification object:nil];


    if (internetStatus == NotReachable)
    {
        NSLog(@"The internet is down.");
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Network Status" 
                                                        message:@"Internet connection is not availbale. Check your connections." delegate:self 
                                              cancelButtonTitle:nil otherButtonTitles:@"OK", nil];

        [alert show];
        [alert release];


    }
    else if (hostStatus == NotReachable)
    {
        NSLog(@"A gateway to the host server is down.");
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Network Status" 
                                                        message:@"Cannot connect to Aghaven server. Please try again later." delegate:self
                                              cancelButtonTitle:nil otherButtonTitles:@"OK", nil];

        [alert show];
        [alert release];

    }




}

Answer 1

You should retain the string value. Do this in loadUrl:

self.myEscapedUrlString  = SearchStr; 

instead of

myEscapedUrlString  = SearchStr;

And it is preferable to declare NSString properties to be copy rather than retain. This way even if the original string were mutable, our instance will remain unchanged.