xcode 如何在另一个视图控制器中调用 NSNotificationCenter 函数？
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How to call a NSNotificationCenter function in another view controller?
提问by pixelbitlabs
Possible Duplicate:
Can I watch an NSNotification from another class?
I am currently using this code below in my appDelegate.m file:
我目前在我的 appDelegate.m 文件中使用以下代码：
- (void)applicationDidEnterBackground:(UIApplication *)application
{
[[NSNotificationCenter defaultCenter] addObserver: self
selector: @selector(handleEnteredBackground:)
name: UIApplicationDidEnterBackgroundNotification
object: nil];
}
However, I want it to call a selector in my viewController.m file. How can I do this?
但是，我希望它在我的 viewController.m 文件中调用一个选择器。我怎样才能做到这一点？
Thanks!
谢谢！
回答by Alan Zeino
Generally, you register the notification first, in your viewController.m initmethod (or somewhere else appropriate):
通常，您首先在 viewController.minit方法（或其他适当的地方）中注册通知：
[[NSNotificationCenter defaultCenter] addObserver: self
selector: @selector(someMethod:)
name: @"NotificationNameHere"
object: nil];
In your App Delegate, fire the notification:
在您的 App Delegate 中，触发通知：
- (void)applicationDidEnterBackground:(UIApplication *)application
{
[[NSNotificationCenter defaultCenter] postNotification: @"NotificationNameHere"];
}
回答by Kevin
in your viewController.m
在你的 viewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
[[NSNotificationCenter defaultCenter] addObserver: self
selector: @selector(handleEnteredBackground:)
name: UIApplicationDidEnterBackgroundNotification
object: nil];
}
回答by krafter
just add this:
只需添加这个：
[[NSNotificationCenter defaultCenter] addObserver: self
selector: @selector(handleEnteredBackground:)
name: UIApplicationDidEnterBackgroundNotification
object: nil];
in your viewController.m viewDidLoad method. (don't forget to create handleEnteredBackground: method)
在您的 viewController.m viewDidLoad 方法中。（不要忘记创建 handleEnteredBackground: 方法）
回答by jbat100
You don't want to register your app delegate for entering background notifications, you already get callbacks for that. It makes even less sense to register your app delegate for these notifications in that callback. You can just, as other posters have suggested add your viewController object as an observer on init (and don't forget to remove yourself on dealloc or you will get bad accesses).
你不想注册你的应用程序委托来输入后台通知，你已经得到了回调。在该回调中为这些通知注册您的应用程序委托更没有意义。您可以像其他海报建议的那样将您的 viewController 对象添加为 init 上的观察者（不要忘记在 dealloc 上删除自己，否则您将获得错误的访问权限）。
回答by daveoncode
If the problem is to access to the delegate from a viewController, you can do:
如果问题是从 viewController 访问委托，您可以执行以下操作：
MYAppDelegate *delegate = (MYAppDelegate *)[[UIApplication sharedApplication] delegate];
[delegate selectorName];
...otherwise clarify your question :P
...否则澄清你的问题：P
