NSObject可以说是OC类的万物之源了,今天我们就来好好看看他的定义.
/* NSObject.h
Copyright (c) 1994-2012, Apple Inc. All rights reserved.
*/
ifndef OBJC_NSOBJECT_H
define OBJC_NSOBJECT_H
if OBJC
include <objc/objc.h>
include <objc/NSObjCRuntime.h>
@class NSString, NSMethodSignature, NSInvocation;
//定义了一个名为NSObject的协议.
@protocol NSObject
- (BOOL)isEqual:(id)object;
//这个方法很常见,我们经常用来比较一个对象是否相同或者值是否相等.相同返回yes.而它是通过什么比较的呢?就是下面的hash值.
@property (readonly) NSUInteger hash;
@property (readonly) Class superclass;//父类.
- (Class)class OBJC_SWIFT_UNAVAILABLE("use 'anObject.dynamicType' instead");//不知道干啥用的.
- (instancetype)self; //返回自己的对象.
//执行一个包装方法.与普通相比,它可以执行到runtime阶段时候才有的方法.下面的不带参数,带一个参数,带两个参数.
- (id)performSelector:(SEL)aSelector;
- (id)performSelector:(SEL)aSelector withObject:(id)object;
- (id)performSelector:(SEL)aSelector withObject:(id)object1 withObject:(id)object2;
//是否从NSObject继承下来的.
- (BOOL)isProxy;
//是不是某个类或者父类的实例 - (BOOL)isKindOfClass:(Class)aClass;
//是不是某个类的实例. - (BOOL)isMemberOfClass:(Class)aClass;
//是不是遵守某个协议. - (BOOL)conformsToProtocol:(Protocol *)aProtocol;
//是不是接受者实现或者继承了某个方法可以响应这个消息. - (BOOL)respondsToSelector:(SEL)aSelector;
//引用计数器加一
- (instancetype)retain OBJC_ARC_UNAVAILABLE;
//引用计数器减一 - (oneway void)release OBJC_ARC_UNAVAILABLE;
//当当前自动释放池释放时释放. - (instancetype)autorelease OBJC_ARC_UNAVAILABLE;
//返回接收对象的引用计数器.不是很准,因为自动释放池可能会推迟释放. - (NSUInteger)retainCount OBJC_ARC_UNAVAILABLE;
//返回一段结构体--对象被分配的区域,价值不大. - (struct _NSZone *)zone OBJC_ARC_UNAVAILABLE;
//接受者的描述.%@ 打印的东西
@property (readonly, copy) NSString *description;
@optional
//同上,不过是在Debug模式下的.
@property (readonly, copy) NSString *debugDescription;
@end
OBJC_AVAILABLE(10.0, 2.0, 9.0, 1.0)
OBJC_ROOT_CLASS
OBJC_EXPORT
//正式开始定义NSObject了.
@interface NSObject <NSObject> {
//类指针.
Class isa OBJC_ISA_AVAILABILITY;
}
//触发,当类或者分类加入Runtimel的时候.
- (void)load;
//是类接受到的第一个消息. - (void)initialize;
//初始化
- (instancetype)init
if NS_ENFORCE_NSOBJECT_DESIGNATED_INITIALIZER
NS_DESIGNATED_INITIALIZER
endif
;
//不知道
- (instancetype)new OBJC_SWIFT_UNAVAILABLE("use object initializers instead");
//历史遗留方法初始分配内存. - (instancetype)allocWithZone:(struct _NSZone *)zone OBJC_SWIFT_UNAVAILABLE("use object initializers instead");
//.. - (instancetype)alloc OBJC_SWIFT_UNAVAILABLE("use object initializers instead");
- (void)dealloc OBJC_SWIFT_UNAVAILABLE("use 'deinit' to define a de-initializer");
//有垃圾回收机制时候代替dealloc. - (void)finalize OBJC_DEPRECATED("Objective-C garbage collection is no longer supported");
//返回调用copyWithZone的结果 - (id)copy;
//返回调用mutableCopyWithZone的结果 - (id)mutableCopy;
//返回接受者.协议不同
- (id)copyWithZone:(struct _NSZone *)zone OBJC_ARC_UNAVAILABLE;
//返回接受者.协议不同. - (id)mutableCopyWithZone:(struct _NSZone *)zone OBJC_ARC_UNAVAILABLE;
//实例化对象是否响应给定的方法 - (BOOL)instancesRespondToSelector:(SEL)aSelector;
//是否遵守协议. - (BOOL)conformsToProtocol:(Protocol *)protocol;
//找出接受者实现方法地址.
- (IMP)methodForSelector:(SEL)aSelector;
//同上,不过是类方法.
- (IMP)instanceMethodForSelector:(SEL)aSelector;
//runtime不能找不到方法时访问
- (void)doesNotRecognizeSelector:(SEL)aSelector;
//重定向 - (id)forwardingTargetForSelector:(SEL)aSelector OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0);
- (void)forwardInvocation:(NSInvocation *)anInvocation OBJC_SWIFT_UNAVAILABLE("");
//返回一个对象包括方法描述的定义. - (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector OBJC_SWIFT_UNAVAILABLE("");
- (NSMethodSignature *)instanceMethodSignatureForSelector:(SEL)aSelector OBJC_SWIFT_UNAVAILABLE("");
//是否允许弱引用
- (BOOL)allowsWeakReference UNAVAILABLE_ATTRIBUTE;
//是否增加弱引用 - (BOOL)retainWeakReference UNAVAILABLE_ATTRIBUTE;
//是否是给定类的子类或者是相同的.
- (BOOL)isSubclassOfClass:(Class)aClass;
//动态的提供一个方法的实现. - (BOOL)resolveClassMethod:(SEL)sel OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0);
- (BOOL)resolveInstanceMethod:(SEL)sel OBJC_AVAILABLE(10.5, 2.0, 9.0, 1.0);
//获得当前hash值 - (NSUInteger)hash;
//获取父类 - (Class)superclass;
- (Class)class OBJC_SWIFT_UNAVAILABLE("use 'aClass.self' instead");
//描述 - (NSString *)description;
//Debug模式下的描述. - (NSString *)debugDescription;
@end
