View does not appear because of i0S 7

View does not appear because of i0S 7

I tried my app on my iPhone with iOS 7 and everything works perfectly
except one thing. On iOS 6 versions, when I executed the following code,
the loading view (with the activityindicator) appeared and disappeared at
the end of the loading. On iOS 7, the view does not appear at all during
the loading.
self.loadingView.alpha = 1.0;
[self performSelector:@selector(accessServices) withObject:nil
afterDelay:0.0f];
AccessServices method :
- (void)accessServices {
// Getting JSON stuff
// The code is OK, I just don't copy/paste it here
self.loadingView.alpha = 0.0;
}
What happens ? Is it an iOS 7 bug ?