为什么我的 UISearchController 委托方法没有被调用？

Question

我在课堂上加入了以下内容：

@interface DiscoverNew() <UISearchResultsUpdating, UISearchBarDelegate, UISearchControllerDelegate>

我在这里设置了UISearchController：

-(void)viewDidLoad {

       [self configureSearchController];

}  

-(void)configureSearchController{

        // Initialize and perform a minimum configuration to the search controller.
        UISearchController *searchController = self.searchController;
        searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
        searchController.searchResultsUpdater = self;
        searchController.dimsBackgroundDuringPresentation = NO;
        searchController.searchBar.placeholder = @"Search for friends...";
        searchController.delegate = self;
        searchController.searchBar.delegate = self;
        [searchController.searchBar sizeToFit];

        [searchController.searchBar setBarStyle:UIBarStyleBlack];
        [searchController.searchBar setSearchBarStyle:UISearchBarStyleMinimal];
        searchController.searchBar.tintColor = [GBColor accentGray];
        searchController.searchBar.backgroundColor = [GBColor darkGray];
        searchController.searchBar.barTintColor = [GBColor accentGray];
        searchController.searchBar.searchTextPositionAdjustment = UIOffsetMake(18.0f, 0.0f);

        // Place searchbar above TableView
        self.tableView.tableHeaderView = searchController.searchBar;

}

如您所见，我调用了searchController.searchBar.delegate = self; searchController 确实出现在它应该出现的位置，并且在点击搜索栏时会显示键盘，但没有调用我的委托方法。怎么回事？

Answer 1

您有一个名为searchController 的属性。但随后您在 configureSearchController 方法中创建了一个同名的局部变量。所以最后你永远不会设置 searchController 属性。结果，您在本地创建的搜索控制器超出范围，没有更多引用，并被释放。

解决方法是稍微更新您的代码。

UISearchController *searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
searchController.searchResultsUpdater = self;
searchController.dimsBackgroundDuringPresentation = NO;
searchController.searchBar.placeholder = @"Search for friends...";
searchController.delegate = self;
searchController.searchBar.delegate = self;
[searchController.searchBar sizeToFit];

[searchController.searchBar setBarStyle:UIBarStyleBlack];
[searchController.searchBar setSearchBarStyle:UISearchBarStyleMinimal];
searchController.searchBar.tintColor = [GBColor accentGray];
searchController.searchBar.backgroundColor = [GBColor darkGray];
searchController.searchBar.barTintColor = [GBColor accentGray];
searchController.searchBar.searchTextPositionAdjustment = UIOffsetMake(18.0f, 0.0f);

self.searchController = searchController;