iOS：使用搜索控制器后重新显示已删除的取消按钮

Question

我在我的应用程序中使用ABPeoplePickerNavigationController，并使用UINavigationControllerDelegate将导航栏按钮覆盖到我自己的按钮。

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    navigationController.topViewController.searchDisplayController.searchBar.barStyle = UIBarStyleBlack;

    navigationController.topViewController.navigationItem.leftBarButtonItem = nil;
    navigationController.topViewController.navigationItem.rightBarButtonItem = nil;

    UIBarButtonItem *cancelButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
                                                                                      target:self
                                                                                      action:@selector(cancel:)];
    navigationController.topViewController.navigationItem.leftBarButtonItem = cancelButtonItem;

    UIBarButtonItem *addButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
                                                                                       target:self
                                                                                       action:@selector(addItem:)];
    navigationController.topViewController.navigationItem.rightBarButtonItem = addButtonItem;

}

这很好用。但是，当我使用搜索控制器退出时，我的右上方按钮突然变为“取消”按钮（见下图）。我怎样才能解决这个问题？提前谢谢。

Answer 1

好的，刚想出如何解决这个问题。我刚刚添加了一个通知，以查看何时隐藏键盘并将按钮添加回导航栏。

1）声明并合成属性mainNavigationController：

@property UINavigationController *mainNavigationController;

2）在（void）navigationController：（UINavigationController *）navigationController didShowViewController：（UIViewController *）viewController animated：（BOOL）animated，add：

mainNavigationController = navigationController;
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(onNotification:) name:UIKeyboardWillHideNotification object:nil];

3）添加onNotification方法：

-(void)onNotification:(NSNotification*)notification
{
    UIBarButtonItem *addButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
                                                                                   target:self
                                                                                   action:@selector(addItem:)];
    mainNavigationController.topViewController.navigationItem.rightBarButtonItem = addButtonItem;
}

Answer 2

要解决此问题，您必须实施<UISearchDisplayDelegate>并在navigationController:willShowViewController:animated:方法中将searchDisplayController的委托设置为自viewController.searchDisplayController.delegate = self;