【iOS學習筆記】Objective-C中根據函數名調用函數

原文出自：http://blog.csdn.net/hopedark/article/details/7970370

 

Objective-C中調用函數的方法是「消息傳遞」，這個和普通的函數調用的區別是，你能夠隨時對一個對象傳遞任何消息，而不須要在編譯的時候聲明這些方法。因此Objective-C能夠在runtime的時候傳遞消息。

主要用到：SEL和@selector，固然還有performSelector

看例子：

先是三個函數：

 

-(void)CallBack0
{
    NSLog(@"CallBack0");
}

-(void)CallBack1:(int)a
{
    NSLog(@"CallBack1:a=%i",a);
}

-(void)CallBack2:(int)a b:(int)b
{
    NSLog(@"CallBack2:a=%i,b=%i",a,b);
}

performSelector調用：

 

 

[self performSelector:@selector(CallBack0)];
[self performSelector:@selector(CallBack1:) withObject:1];
[self performSelector:@selector(CallBack2:b:) withObject:1 withObject:2];

 

 

根據函數名動態調用：

 

NSString *a=@"CallBack0";
SEL faSelector=NSSelectorFromString(a);
[self performSelector:faSelector];

NSString *b=@"CallBack1:";
SEL fbSelector=NSSelectorFromString(b);
[self performSelector:fbSelector withObject:1];

NSString *c=@"CallBack2:b:";
SEL fcSelector=NSSelectorFromString(c);
[self performSelector:fcSelector withObject:1 withObject:2];

這樣就能夠根據函數名調用函數啦！