filterContentForSearchText:scope: 方法从哪里来？

最近，我注意到filterContentForSearchText:scope:出现在有关如何实现搜索栏的多个教程中。

不过，我查阅了两者的参考资料UISearchDisplayDelegate and UISearchBarDelegate。我找到了这个filterContentForSearchText:scope:既不是必需的也不是可选的方法。

我想知道是否filterContentForSearchText:scope:只是一个过滤搜索结果的常规方法名称？

是的，这只是从UISearchDisplayDelegate methods

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString;
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchScope:(NSInteger)searchOption;

目前的“具有状态恢复的简单 UISearchBar” https://developer.apple.com/library/ios/samplecode/TableSearch/Introduction/Intro.htmlApple 的示例项目确实not使用这个约定：

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
    NSString *scope;

    NSInteger selectedScopeButtonIndex = [self.searchDisplayController.searchBar selectedScopeButtonIndex];
    if (selectedScopeButtonIndex > 0)
    {
        scope = [[APLProduct deviceTypeNames] objectAtIndex:(selectedScopeButtonIndex - 1)];
    }

    [self updateFilteredContentForProductName:searchString type:scope];

    // Return YES to cause the search result table view to be reloaded.
    return YES;
}