KVO vs NSNotification vs protocol / delegates？ [英] KVO vs NSNotification vs protocol/delegates?

问题描述

虽然我有一些想法可以使用，但确切用法仍然不清楚。有人可以用例子解释......？谢谢。

Though I have some idea which to use when but the exact usage is still not clear to me. Can someone explain with example...? Thanks.

推荐答案

如果只想与一个对象交谈，请使用委托。例如，tableView有一个委托 - 只有一个对象负责处理它。

Use a delegate if you want to talk to only one object. For example, a tableView has a delegate - only one object should be responsible for dealing with it.

如果你想告诉大家发生了什么事情，请使用通知。例如，在内存不足的情况下，会发送通知，告知您的应用程序存在内存警告。由于您应用中的大量对象可能希望降低其内存使用量，因此这是一个通知。

Use notifications if you want to tell everyone that something has happened. For example in low memory situations a notification is sent telling your app that there has been a memory warning. Because lots of objects in your app might want to lower their memory usage it's a notification.

我认为KVO根本不是一个好主意并且尽量不要使用但是，如果你想知道一个房产是否已经改变，你可以听取更改。

I don't think KVO is a good idea at all and try not to use it but, if you want to find out if a property has changed you can listen for changes.

希望有所帮助。

PS 这总结了我认为KVO被打破的原因

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