如何从Objective-C中的字符串实例化类的对象?

1) what does NSClassFromString return??

它返回一个类,这意味着您可以 [[NSClassFromString(@"MyClass") alloc] init]; 看见 Mac Dev Center Docs 更多信息。

2) what is id?

见 http://www.otierney.net/objective-c.html#idtype

3) How to call method -(void)FunctioninClass which is in MyClass using the instance.

id myclass = [[NSClassFromString(@"MyClass") alloc] init];
[myclass FunctioninClass];