消除模态视图层次结构——一个优雅的解决方案
我有一个像这样的视图层次结构：
- 从应用程序委托中显示的自定义视图控制器（例如视图控制器 1）。
- 另一个视图控制器（比如视图控制器 2）从视图控制器 1 模态显示。
- 另一个视图控制器（比如视图控制器 3）从视图控制器 2 模态显示。
- 还有一个视图控制器（比如视图控制器 4）我需要遵循步骤2& 3.
现在，在某些活动中，我需要取消整个模式视图层次结构。所以我正在做的是，我从视图控制器 3 发送有关该事件的通知，并在视图控制器中侦听该通知，然后执行：
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"cancelViews" object:nil];
这可行，但有一个问题。根据我的应用程序流程，我最终在视图控制器 1 和视图控制器 4 上注册此通知。现在，当视图控制器 1 的整个模式层次结构启动并且通知由 VC1 注册，然后在另一个视图层次结构之上注册时显示了视图控制器 4，最后当引发通知时，我的视图层次结构都消失了。
我只希望最顶层的视图层次结构消失。任何解决方案都会真正有帮助。
I have a view hierarchy like this:
- A custom view controller (Say view controller 1) shown from app delegate.
- Another view controller (Say view controller 2) shown modally from view controller 1.
- Another view controller (Say view controller 3) shown modally from view controller 2.
- There is one more view controller (Say view controller 4) from which I need to follow step 2 & 3.
Now on some activity I need to cancel the whole modal view hierarchy. So what I am doing is, I am sending a notification on that event from view controller 3 and listeneing to that notification in view controller and then executing:
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"cancelViews" object:nil];
This works but there is one problem. As per my app flow I am ending up registering for this notification at both view controller 1 and view controller 4. Now, when whole modal hierarchy for view controller 1 was up and notification was registered by VC1 and then on top of that another view hierarchy for view controller 4 is shown and finally when notification is thrown both my view hierarchy disappears.
I want only my top most view hierarchy to be disappeared. Any solution for this will really help.
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使用 代表！
如果这不是您想要采取的路线（尽管我强烈鼓励您这样做），您可以设置 1 和 4 视图控制器来发布根视图控制器将侦听的不同事件。
Use delegates!
If that isn't a route you want to take (even though I strongly encourage you to do so) you can setup your 1 and 4 view controller to publish different events for which your root view controller will listen.