NSNotificationCenter与授权（使用协议）？ [英] NSNotificationCenter vs delegation( using protocols )?

问题描述

解决方案

这里的经验法则是有多少客户希望被通知事件。如果它主要是一个对象（例如，关闭视图或者对点击的按钮进行操作或对失败的下载进行响应），那么您应该使用委托模型。

如果您发出的事件可能会对许多对象立即感兴趣（例如屏幕旋转，内存使用，用户登录/注销），那么您应该使用 NSNotificationCenter 。 / p>

What are the pros and cons of each of them?
Where should I use them specifically?

解决方案

The rule of thumb here is how many clients would like to be notified of an event. If it's mainly one object (e.g. to dismiss a view or to act upon a button clicked, or to react to a failed download) then you should use the delegate model.

If the event you emit may be of an interest to many objects at once (e.g. screen rotated, memory usage, user login/logout), then you should use the NSNotificationCenter.

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