从字符串对类动态调用静态方法

NSString * className = "MyClass";
NSString * methodName = "doSomething";

Class class = NSClassFromString(@"MyClass");
SEL selector = NSSelectorFromString(@"doSomething");
[class performSelector:selector];

这会给你一个警告"PerformSelector可能会导致泄漏，因为它的选择器未知"，你可以这样忽略它（有关详细信息，请参阅此问题）：

Class class = NSClassFromString(@"MyClass");
SEL selector = NSSelectorFromString(@"doSomething");    
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
[class performSelector:selector];
#pragma clang diagnostic pop

[NSClassFromString(className) performSelector:NSSelectorFromString(methodName)];