iSearchDisplayController结果表在iOS7中的位置问题

试图在UINavigationBar中实现UISearchBar我的结果表视图位置出错图2：

我花了几天时间来解决这个问题，但没有成功

谢谢

编辑

在我的视图中：

[self.searchDisplayController.searchBar setPlaceholder:NSLocalizedString(@"SEARCH_PLACEHOLDER", nil)];
[self.searchDisplayController setDisplaysSearchBarInNavigationBar:YES];

我的SearchDisplayController委托方法：

-(void)filterContentForSearchText:(NSString*)searchText scope:(NSString*)scope
{
     //filter work repfectly
}

-(BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
     [self filterContentForSearchText:searchString
                           scope:[[self.searchDisplayController.searchBar scopeButtonTitles]
                                  objectAtIndex:[self.searchDisplayController.searchBar selectedScopeButtonIndex]]];

     return YES;
}

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar
{
    NSPredicate *resultPredicate = [NSPredicate predicateWithFormat:@"not (isFav == 100)"];

    [_fetchedResultsController.fetchRequest setPredicate:resultPredicate];
    [self performFetch];
}