objective-c中类似于method_missing的功能（即运行时的动态委派） [英] method_missing-like functionality in objective-c (i.e. dynamic delegation at run time)

问题描述

我正在尝试将一个方法调用动态转换（在运行时）。

I'm trying to transform one method call into another dynamically (at runtime).

例如，我想要如下：

[obj foo]

委托给：

[obj getAttribute: @"foo"]

'我喜欢做这个动态，因为我不提前知道这些方法的名称或属性将是什么）。

(I'd like to do this dynamically as I don't know ahead of time what those method names or attributes are going to be).

我看到有一个钩子：

 - (id) forwardingTargetForSelector: (SEL) aSelector

尽管如此，我只想保持对象为self，并转换方法参数。

That only seems to work for delegation, though, I want to keep the object as "self" and transform the method arguments.

我应该在哪里寻找这种行为？您可以使用方法 -forwardInvocation：

Where should I look for this sort of behavior? Is it even possible in obj-c?

推荐答案

code>为此。它需要一个完整的 NSInvocation 对象，表示方法调用，您可以处理它，但是您希望。如果这样做，您还应该覆盖 -methodSignatureForSelector：以返回正确的 NSMethodSignature （ -forwardInvocation：在未知选择器上工作）。还建议您覆盖 -respondsToSelector：以声明您可以处理相关的选择器。

You can use the method -forwardInvocation: for that. It takes a full NSInvocation object which represents the method call, and you can handle it however you wish. If you do this, you should also override -methodSignatureForSelector: to return the correct NSMethodSignature (required for -forwardInvocation: to work on unknown selectors). It's also recommended that you override -respondsToSelector: to declare that you can handle the selector in question.

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