alertView:(UIAlertView *) alertView method not working in Appdelegate

I had set UIAlertView in AppDelegate.m file.

But when I choose the button on the alert view.

-(void) alertView:(UIAlertView *) alertView clickedButtonAtIndex:(NSInteger)buttonIndex

was not working.

I had set UIAlertViewDelegate in the AppDelegate.h file.

and my AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:        (NSDictionary *)launchOptions
        {

         [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(reachabilityChanged:)
                                                 name:kReachabilityChangedNotification
                                               object:nil];

            NSString *remoteHostName = REACHABILITY_HOST;
            _hostReachability = [Reachability reachabilityWithHostName:remoteHostName];
            [_hostReachability startNotifier];

            return YES;
        }

        - (void) reachabilityChanged:(NSNotification *)note
        {
         if( [Reachability isExistNetwork] == NotReachable)
            {
                UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:nil         message:@"my message" delegate:nil cancelButtonTitle:@"ok"         otherButtonTitles:@"set",nil];
                [alertView show];

            }

        }

        -(void) alertView:(UIAlertView *) alertView clickedButtonAtIndex:(NSInteger)buttonIndex
        {

            switch (buttonIndex) {

                case 0:
                    NSLog(@"ok!");
                    break;

                    // set
                case 1:

                    NSLog(@"set!");
                    NSURL*url=[NSURL URLWithString:@"prefs:root=WIFI"];
                    [[UIApplication sharedApplication] openURL:url];
                    break;

            }
        }

But the

-(void) alertView:(UIAlertView *) alertView clickedButtonAtIndex:(NSInteger)buttonIndex

was not enter this method.

Have anyone know what happened? thanks.

Your code doesn't correctly set the delegate of the alert view.

You need to change the following line so that the delegate is the appropriate object (eg, self):

UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:nil         message:@"my message" delegate:nil cancelButtonTitle:@"ok"         otherButtonTitles:@"set",nil];