isKindOfClass:[NSObject class]
isMemberOfClass:[NSObject class]
conformsToProtocol:@protocol(NSCopying)
respondsToSelector:@selector(showMessage:)
動態生成一個類
NSString *className=@"Person"; Class myClass=NSClassFromString(className)
可以用 myClass 初始化Person對象
Person *person2=[[myClass alloc]init]
NSStringFromClass(myClass),NSStringFromClass([Person class]
NSString *methodName=@"showMessage:" // 方法名字符串
SEL mySelector=NSSelectorFromString(methodName); // 根據方法名字符串 創建SEL對象
NSStringFromSelector(mySelector)