@selector-有多个参数? [英] @selector - With Multiple Arguments?

问题描述

我今天第一次使用@selector，还无法确定如何执行以下操作?如果您有多个参数，您将如何编写@selector?

I have been using @selector today for the first time and have not been able to work out how to do the following? How would you write the @selector if you had more than one argument?

没有参数:

-(void)printText {
    NSLog(@"Fish");
}

[self performSelector:@selector(printText) withObject:nil afterDelay:0.25];

单个参数:

-(void)printText:(NSString *)myText {
    NSLog(@"Text = %@", myText);
}

[self performSelector:@selector(printText:) withObject:@"Cake" afterDelay:0.25];

两个参数:

-(void)printText:(NSString *)myText andMore:(NSString *)extraText {
    NSLog(@"Text = %@ and %@", myText, extraText);
}

[self performSelector:@selector(printText:andMore:) withObject:@"Cake" withObject:@"Chips"];

多个参数:(即大于2个)

Multiple Arguments: (i.e. more than 2)

NSInvocation

推荐答案

 

 - (id)performSelector:(SEL)aSelector
           withObject:(id)anObject  
           withObject:(id)anotherObject

从文档:

此方法与 performSelector相同:，除了可以为aSelector提供两个参数. aSelector应该确定一个可以接受两个类型为id的参数的方法.对于具有其他参数类型和返回值的方法，请使用 NSInvocation .

This method is the same as performSelector: except that you can supply two arguments for aSelector. aSelector should identify a method that can take two arguments of type id. For methods with other argument types and return values, use NSInvocation.

因此，在您的情况下，您将使用:

so in your case you would use:

[self performSelector:@selector(printText:andMore:)
           withObject:@"Cake"
           withObject:@"More Cake"]

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