UINavgationController push视图的时候距离顶端20距离

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    
    [self.navigationController setNavigationBarHidden:YES animated:YES];
}
    - (void)viewDidLoad
{
    [super viewDidLoad];
//    self.title = @"全部品牌";
    
    
    self.automaticallyAdjustsScrollViewInsets = NO;
    
    
}