“-(void)encodeWithCoder:(NSCoder *)aCoder{

unsigned int outCount;

Ivar *ivarList = class_copyIvarList([Person class], &outCount);

for (NSInteger i = 0; i < outCount; i++) {

const char *cName = ivar_getName(ivarList[i]);

NSString *name = [NSString stringWithUTF8String:cName];

[aCoder encodeObject:[self valueForKey:name] forKey:name];

}

}

-(instancetype)initWithCoder:(NSCoder *)aDecoder

{

self = [super init];

if (self) {

unsigned int outCount;

Ivar *ivarList = class_copyIvarList([Person class], &outCount);

for (NSInteger i = 0; i < outCount; i++) {

const char *cName = ivar_getName(ivarList[i]);

NSString *name = [NSString stringWithUTF8String:cName];

[self setValue:[aDecoder decodeObjectForKey:name] forKey:name];

}

}

return self;

}

/*

Ivar *class_copyIvarList(Class cls, unsigned int *outCount)      //获取所有成员变量

const char *ivar_getName(Ivar v)            //获取某个成员变量的名字

const char *ivar_getTypeEncoding(Ivar v)  //获取某个成员变量的类型编码

Ivar class_getInstanceVariable(Class cls, const char *name)    //获取某个类中指定名称的成员变量

id object_getIvar(id obj, Ivar ivar)    //获取某个对象中的某个成员变量的值

void object_setIvar(id obj, Ivar ivar, id value)    //设置某个对象的某个成员变量的值

TypeEncoding：https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtTypeEncodings.html#//apple_ref/doc/uid/TP40008048-CH100-SW1

*/

-(NSString *)description{

/** class:要获取的某个类， outCount:通过一个函数执行之后会将成员变量的数值赋值到此 */

unsigned int outCount;

Ivar *ivarList = class_copyIvarList([Person class], &outCount);

for (NSInteger i = 0; i < outCount; i++) {

//每次获取一个成员变量

Ivar ivar = ivarList[i];

//打印成员变量的名字和类型编码

NSLog(@"name = %s, type = %s", ivar_getName(ivar),ivar_getTypeEncoding(ivar));

}

return nil;

}

+(Person *)personWithName:(NSString *)name gender:(NSString *)gender age:(NSNumber *)age weight:(NSInteger)weight

{

Person *person = [Person new];

unsigned int outCount;

Ivar *ivarList = class_copyIvarList(self, &outCount);

// obj:要设置的对象 ivar：要设置的对象的某一个属性 value:value

object_setIvar(person, ivarList[0], name);

object_setIvar(person, ivarList[1], gender);

object_setIvar(person, ivarList[2], age);

object_setIvar(person, ivarList[3], @(weight));

return person;

}

-(void)getPersonMessage

{

unsigned int outCount;

Ivar *ivarList = class_copyIvarList([Person class], &outCount);

for (NSInteger i = 0; i < outCount; i++) {

NSLog(@"name = %s, value = %@", ivar_getName(ivarList[i]), object_getIvar(self, ivarList[i]));

}

}

/*

1    + resolveInstanceMethod:(SEL)sel      // 为一个实例方法动态添加实现

+ resolveClassMethod:(SEL)sel      //  为一个类方法动态添加实现

2    - (id)forwardingTargetForSelector:(SEL)aSelector

//为没有实现的方法指定一个对象

3    - (void)forwardInvocation:(NSInvocation *)anInvocation

//子类重载这个方法为消息指定其他对象

*/

//消息转化1：为一个实例方法动态添加实现

+ (BOOL)resolveInstanceMethod:(SEL)sel{

NSString *selString = NSStringFromSelector(sel);

if ([selString isEqualToString:@"wolkOnTheStreet:"]) {

// 为一个没有实现的方法添加实现

/** cls:类

name:没有实现的方法

IMP:要添加的方法

types:动态添加的实现的类型编码

*/

class_addMethod(self, @selector(wolkOnTheStreet:), (IMP)wolkFunc, "V@:@");

}

return [super resolveInstanceMethod:sel];

}

void wolkFunc(id self,SEL sel, NSString *str){

NSLog(@"Person---%s---%@",  __func__,str);

}

- (id)forwardingTargetForSelector:(SEL)aSelector

{

NSString *selString = NSStringFromSelector(aSelector);

if ([selString isEqualToString:@"wolkOnTheStreet:"]) {

self.dog = [Dog new];

return self.dog;

}

return [super forwardingTargetForSelector:aSelector];

}

//切换消息转化对象：二

- (void)forwardInvocation:(NSInvocation *)anInvocation

{

if ([Dog instancesRespondToSelector:anInvocation.selector]) {

self.dog = [Dog new];

[anInvocation invokeWithTarget:self.dog];

}

}

//给方法制定一个有效的签名

-(NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector

{

NSMethodSignature *methodSignature = [super methodSignatureForSelector:aSelector];

if (!methodSignature) {

methodSignature = [Dog instanceMethodSignatureForSelector:aSelector];

}

return methodSignature;

}”