Question

我的应用包含一个带有两个标签的tabBarController。标签号0包含SearchViewController，标签号1包含MatchCenterViewController。我想要做的是在切换到该选项卡之前设置MatchCenterViewController s didAddNewItem属性的值。我知道，如果我用segue做了这个，那就这样做了：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"ShowMatchCenterSegue"]) {
        MatchCenterViewController *controller = (MatchCenterViewController *) segue.destinationViewController;

        self.didAddNewItem = 1;
        controller.didAddNewItem = self.didAddNewItem;
    }
}

但是我不想用segue执行此操作，我希望在调用didAddNewItem之前设置MatchCenterViewController [self.tabBarController setSelectedIndex:1];。是否有可能做到这一点？

Answer 1

您应该可以从[self.tabBarController viewControllers]

中提取视图控制器

一些伪代码供你尝试和搞乱：

UIViewController *toViewController = [self.tabBarController viewControllers][1];
if ([toViewController isKindOfClass:[MatchCenterViewController class]]) { // This is just for the sake of safety. Good practice to get into type checking before you cast.
    MatchCenterViewController *matchViewController = (MatchCenterViewController *)toViewController;
    matchViewController.didAddNewItem = true; // Really this should be a Bool!
}
[self.tabBarController setSelectedIndex:1];

Answer 2

最好使用协议和委托，这是将此数据传递给另一个视图控制器的最简洁方法。它还将您的代码分离，以便以后更容易管理。例如，您构建的iPad版本没有UITabbarController。

Define a protocol in SearchViewController.h:

//under the #import
@protocol SearchViewControllerDelegate

//define a property to send delegate messages to
@property (nonatomic,strong) id <SearchViewControllerDelegate> delegate;

//after @end
@protocol SearchViewControllerDelegate <NSObject>
- (void)searchViewControllerDidSearchWithResult:(NSArray *)result;

Then when you are setting up the view controllers assign MatchViewController to be the SearchViewControllers delegate.

//in SearchViewController.m send the delegate message
[self.delegate searchViewControllerDidSearchWithResult:arr];

Then in MatchViewController adopt the protocol to get messages.

在切换tabBarController索引而不是segueing时，将数据从一个ViewController传递到另一个ViewController

2 个答案: