iphone - 使用字符串中的对象运行方法

Question

在我的代码的某一点，我将方法作为字符串引用，并且我有它们的目标。例如，假设我有一个名为 myObject 的对象，并且有一个名为“doSomething:”的方法，如下所示:

- (void)doSomething:(id)sender {
   // do something baby
}

在我的代码的某一点，我存储了对执行此操作的对象和方法的引用:

NSString *myMethod = @"doSomething:";
id myTarget = myObject;

稍后，在代码的另一点我想这样做

[myObject doSomething:self];

但是如何从对象的引用 id 以及表示该方法的 NSString 重建对该对象的方法调用，以及如何将 self 传递给该方法？

谢谢

Answer 1

要将字符串转换为选择器，请使用NSSelectorFromString。相反，请使用 NSStringFromSelector。

转换选择器:

SEL selector = NSSelectorFromString(methodSelectorString);

调用方法:

[myObject performSelector:selector withObject:self afterDelay:0.0];

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来自Foundation reference ;

NSSelectorFromString

返回具有给定名称的选择器。

SEL NSSelectorFromString (
   NSString *aSelectorName
);

参数

aSelectorName

A string of any length, with any characters, that represents the name of a selector. Return Value The selector named by aSelectorName. If aSelectorName is nil, or cannot be converted to UTF-8 (this should be only due to insufficient memory), returns (SEL)0.

Discussion To make a selector, NSSelectorFromString passes a UTF-8 encoded character representation of aSelectorName to sel_registerName and returns the value returned by that function. Note, therefore, that if the selector does not exist it is registered and the newly-registered selector is returned.

Recall that a colon (“:”) is part of a method name; setHeight is not the same as setHeight:. For more about methods names, see “Objects, Classes, and Messaging” in The Objective-C Programming Language.

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NSStringFromSelector

返回给定选择器的字符串表示形式。

NSString *NSStringFromSelector (
   SEL aSelector
);