UISearchController

UISearchBar   http://blog.sina.com.cn/s/blog_7b9d64af0101dfg8.html

UISearchController  

//创建

    self.searchC = [[UISearchController alloc] initWithSearchResultsController:nil];

//设置代理

    self.searchC.searchResultsUpdater = self;

    self.searchC.delegate = self;

    self.searchC.searchBar.delegate = self;    //然后searchbar的代理方法就可以用了

    self.searchController.searchBar.placeholder = NSLocalizedString(@"UISearchController", @"please add string file"); 

//设置UISearchController的显示属性，以下3个属性默认为YES
    //搜索时，背景变暗色
    _searchController.dimsBackgroundDuringPresentation = NO;
    //搜索时，背景变模糊
    _searchController.obscuresBackgroundDuringPresentation = NO;
    //隐藏导航栏
    _searchController.hidesNavigationBarDuringPresentation = NO;

    //设置searchbar自适应位置

    [self.searchC.searchBar sizeToFit];

    //设置背景颜色

    self.searchC.searchBar.barTintColor = [UIColor yellowColor];

//搜索栏的内容发生变化时, 会触发代理方法

- (void)updateSearchResultsForSearchController:(UISearchController *)searchController;