UISearchController和SearchResultsTableView之间的额外空间

Question

我在i-9的objective-c中使用UISearchController并面临一个非常不寻常的问题，请参阅下图：

我用self.automaticallyAdjustsScrollViewInsets = NO;尝试了各种各样的事情 并且重新构思视图，但没有任何作用，任何人都可以帮忙解决这个问题吗？

下面是我设置UISearchController的代码

 UITableViewController *searchResultsController = [[self storyboard] instantiateViewControllerWithIdentifier:@"SearchResultsViewController"];

    self.searchController=[[UISearchController alloc]initWithSearchResultsController:searchResultsController];
    self.searchController.searchResultsUpdater=self;
    self.searchController.dimsBackgroundDuringPresentation=NO;
    self.searchController.searchBar.placeholder = @"Enter city";
    self.searchController.searchBar.delegate = self;
    self.searchController.searchBar.tintColor=[UIColor whiteColor];
    self.searchController.searchBar.backgroundColor=[UIColor blackColor];
    self.searchController.searchBar.barTintColor=[UIColor blackColor];
    self.searchTableView.tableHeaderView = self.searchController.searchBar;
    self.searchController.hidesNavigationBarDuringPresentation=YES;