如何摆脱“未声明选择器"警告

问题描述

我想在NSObject实例上使用选择器，而无需实现协议.例如，如果要调用的NSObject实例支持它，则有一个category方法应该设置一个error属性.这是代码，并且代码按预期工作:

I want to use a selector on an NSObject instance without the need for an implemented protocol. For example, there's a category method that should set an error property if the NSObject instance it's called on supports it. This is the code, and the code works as intended:

if ([self respondsToSelector:@selector(setError:)])
{
    [self performSelector:@selector(setError:) withObject:[NSError errorWithDomain:@"SomeDomain" code:1 userInfo:nil]];
}

但是，编译器在setError:签名周围看不到任何方法，因此对于包含@selector(setError:)代码段的每一行，它都会向我发出警告:

However, the compiler doesn't see any method around with the setError: signature, so it gives me a warning, for each line that contains the @selector(setError:) snippet:

Undeclared selector 'setError:'

我不想声明一个协议来摆脱此警告，因为我不希望所有可能使用该类的类来实现任何特殊的东西.按照约定，我希望它们具有setError:方法或属性.

I don't want to have to declare a protocol to get rid of this warning, because I don't want all classes that may use this to implement anything special. Just by convention I want them to have a setError: method or property.

这可行吗?怎么样?

干杯，
EP

Cheers,
EP

推荐答案

另一种选择是通过以下方式禁用警告:

Another option would be to disable the warning with:

#pragma GCC diagnostic ignored "-Wundeclared-selector"

您可以将此行放置在发生警告的.m文件中.

You can place this line in the .m file where the warning occurs.

更新:

它也可以像这样与LLVM一起使用:

It works also with LLVM like this:

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wundeclared-selector"

... your code here ...

#pragma clang diagnostic pop

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