iPhone:@selector语法不同 [英] iPhone: Difference in @selector syntax

问题描述

最有可能是一个愚蠢的问题，但是两者之间有什么区别?

Most likely a dumb question, but what's the difference between:

UIBarButtonItem *anotherButton = [[UIBarButtonItem alloc] initWithTitle:@"Join" style:UIBarButtonItemStylePlain
                                target:self action:@selector(pressJoinButton)];

和

UIBarButtonItem *anotherButton = [[UIBarButtonItem alloc] initWithTitle:@"Join" style:UIBarButtonItemStylePlain
                                target:self action:@selector(pressJoinButton:)];

请注意一个是pressJoinButton，另一个是pressJoinButton:

Notice how one is pressJoinButton, and the other is pressJoinButton:

推荐答案

冒号用于向要调用的方法添加参数，因此，如果pressJoinButton的参数为零，则为:

The colon is used to add arguments to the method you are calling, so if pressJoinButton had zero arguments, it would be:

pressJoinButton

如果有一个参数，则为:

If it had one argument, it would be:

pressJoinButton:

如果有2个参数，则为:

if it had 2 arguments, it would be:

pressJoinButton:withArg1:

如果有3个参数，则为:

if it had 3 arguments it would be:

pressJoinButton:withArg1:withArg2:

等

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