IOS UITableView contentOffSet在从推送的详细视图返回时不再隐藏标头

- (void) viewWillAppear:(BOOL)animated {
    [self.navigationController setNavigationBarHidden:YES animated:animated];
    [super viewWillAppear:animated];
    self.tableView.contentOffset 
     = CGPointMake(0, self.tableView.tableHeaderView.frame.size.height);
    //it\'s as if the line above is ignored on when returning from a pushed detail view    
}

- (void) viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    // theContentOffSet works when I put it hear, but then the user can see it which is not desired    
}

-(void)viewWillAppear:(BOOL)animated
{
    [self performSelector:@selector(updateContentOffset) withObject:nil afterDelay:0.0];
}

- (void)updateContentOffset
{
    self.tableView.contentOffset = CGPointMake(0, savedContentOffsetY);
}

viewWillDisappear

savedContentOffsetY = self.tableView.contentOffset.y;

viewDidLoad

savedContentOffsetY = self.tableView.tableHeaderView.frame.size.height;

self.edgesForExtendedLayout = UIRectEdgeNone;