NSObject学习

- (id)copy
//Returns the object returned by copyWithZone:.调用copyWithZone方法实现复制功能，若是自己的类

//则需要实现copyWithZone方法

如：NSString *str2 = [str1 copy];

+ (id)copyWithZone:(struct _NSZone *)zone//copy方法的实现者

-(id)
copyWithZone:(NSZone *)zone

{

Engine * engineCopy;

copyWithZone = [[[self class]allocWithZone:zone]init];

Return(engineCopy)

}

- (id)mutableCopy//同copy,这里获得的是可变的对象

如：NSMutableString
* mutableStr1= [str1 mutableCopy];

+ (id)mutableCopyWithZone:(struct _NSZone *)zone//不关注

+ (Class)class//Returns
the class object. 返回类对象

BOOL
test
= [self
isKindOfClass:[SomeClass
class]];

+ (Class)superclass//Returns
the class object for the receiver’s superclass.
返回父类的类对象

+
(BOOL)isSubclassOfClass:(Class)aClass//判断消息接收者所属的类是不是aClass的子类

+ (BOOL)instancesRespondToSelector:(SEL)aSelector//判断对象能否相应给定的选择器（方法）

+ (BOOL)conformsToProtocol:(Protocol
*)aProtocol//判断对象是否实现给定的协议

……

+ (NSString *)description//描述

- (void)performSelector:(SEL)aSelectorwithObject:(id)anArgumentafterDelay:(NSTimeInterval)delay

Invokes a method of the receiver on the current thread using the default mode after a delay.

- (BOOL)isKindOfClass:(Class)aClass

Returns a Boolean value that indicates whether the receiver is an instance of given class or an instance of any class that inherits from that class. (required)

- (BOOL)isMemberOfClass:(Class)aClass

Returns a Boolean value that indicates whether the receiver is an instance of a given class. (required)

是不是给定类的子类

- (BOOL)respondsToSelector:(SEL)aSelector

Returns a Boolean value that indicates whether the receiver implements or inherits a method that can respond to a specified message. (required)

- (BOOL)conformsToProtocol:(Protocol
*)aProtocol

Returns a Boolean value that indicates whether the receiver conforms to a given protocol. (required)

- (id)performSelector:(SEL)aSelector

Sends a specified message to the receiver and returns the result of the message. (required)

- (id)performSelector:(SEL)aSelector
withObject:(id)anObject//同上，object是传入的参数可为nil

……