gistfile1.m

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    [self.navigationController setNavigationBarHidden:NO animated:animated];
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    
    [self.navigationController setNavigationBarHidden:NO animated:animated];
    
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.01 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
        [self.navigationController setNavigationBarHidden:NO animated:NO];
    });
}