何时调用searchDisplayController委托方法？

Question

我将我的searchDisplayController和searchBar设置如下：

UISearchBar *aSearchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 150, 44)];
self.reportSearchBar = aSearchBar;
_reportSearchBar.tintColor = DARKGRAY_COLOR;
_reportSearchBar.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
_reportSearchBar.delegate = self;
[aSearchBar release];

UISearchDisplayController *searchDisplayCtlr = [[UISearchDisplayController alloc] initWithSearchBar:self.reportSearchBar contentsController:self];
self.reportSearchDisplayController = searchDisplayCtlr;
self.reportSearchDisplayController.searchResultsDataSource = self;
self.reportSearchDisplayController.searchResultsDelegate = self;
[searchDisplayCtlr release];

UIBarButtonItem *searchBBI = [[UIBarButtonItem alloc] initWithCustomView:_reportSearchBar];
self.reportSearchBBI = searchBBI;
[searchBBI release];

[self.navigationItem setRightBarButtonItem:_reportSearchBBI animated:NO];

我检查了我的ViewController是否符合类，以防万一：

if ([self conformsToProtocol:@protocol(UISearchDisplayDelegate)]) {
    NSLog(@"conform to search display");
}

我的ViewController .h文件包含：

<UITableViewDelegate, UITableViewDataSource, UISearchBarDelegate, UISearchDisplayDelegate>

但是，我将中断点设置为

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
    [self filterContentForSearchText:searchString];

    return YES;
}

它永远不会到达那里。我实现了其中一个UISearBarDelegate方法，它确实到达了那个方法。当我运行苹果的示例代码TableSearch时，上面复制的searchDisplayController委托方法确实会运行。所以对我来说，我试图在搜索栏中输入文本，但我的应用程序崩溃了，因为过滤后的列表中没有对象，因为searchDisplayController委托从未被调用过。

有什么想法？谢谢!

Answer 1

我只是在苹果的参考资料中看到：

searchController = [[UISearchDisplayController alloc]
                     initWithSearchBar:searchBar contentsController:self];
searchController.delegate = self;
searchController.searchResultsDataSource = self;
searchController.searchResultsDelegate = self;

我没有在你的代码中看到searchController.delegate = self，这不是必要的吗？

http://developer.apple.com/library/ios/#DOCUMENTATION/UIKit/Reference/UISearchDisplayController_Class/Reference/Reference.html

Answer 2

确保在头文件中为UISearchDisplayController创建一个iVar。

如果您使用以下命令创建UISearchDisplayController：

UISearchDisplayController* searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchField contentsController:self];

它将由ARC释放，它不会调用任何委托方法，当您将调用self.searchDisplayController (UIViewController的属性)时，它将是nil。

因此，修复方法是:在您的头文件(.h)中：

@interface MenuViewController : UIViewController <UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate, UISearchDisplayDelegate> {
        UISearchDisplayController* searchDisplayController;
        UISearchBar *searchField;
        UITableView* tableView;
        NSArray* searchResults;
}

在实现(.m)文件中：

searchField = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 49)];
searchField.delegate = self;

searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:searchField contentsController:self];
searchDisplayController.delegate = self;
searchDisplayController.searchResultsDataSource = self;
searchDisplayController.searchResultsDelegate = self;

tableView.tableHeaderView = searchField;
tableView.contentOffset = CGPointMake(0, searchField.frame.size.height);

这样实现后，您可以在其余代码中同时调用self.searchDisplayController和searchDisplayController。