// OC代碼:
[Person coding];

//運(yùn)行時(shí) runtime 會(huì)將它轉(zhuǎn)化成 C 語言的代碼:
objc_msgSend(Person, @selector(coding));

// 遍歷某個(gè)類所有的成員變量
class_copyIvarList

// 遍歷某個(gè)類所有的方法
class_copyMethodList

// 獲取指定名稱的成員變量
class_getInstanceVariable

// 獲取成員變量名
ivar_getName

// 獲取成員變量類型編碼
ivar_getTypeEncoding

// 獲取某個(gè)對象成員變量的值
object_getIvar

// 設(shè)置某個(gè)對象成員變量的值
object_setIvar

// 給對象發(fā)送消息
objc_msgSend

 unsigned int count = 0;
 // 動(dòng)態(tài)獲取類中的所有屬性(包括私有)
 Ivar *ivar = class_copyIvarList(_person.class, &count);
 // 遍歷屬性找到對應(yīng)字段
 for (int i = 0; i < count; i ++) {
  Ivar tempIvar = ivar[i];
  const char *varChar = ivar_getName(tempIvar);
  NSString *varString = [NSString stringWithUTF8String:varChar];
  if ([varString isEqualToString:@"_name"]) {
   // 修改對應(yīng)的字段值
   object_setIvar(_person, tempIvar, @"更改屬性值成功");
   break;
  }
 }

- (void)setName:(NSString *)name {
 objc_setAssociatedObject(self, @"name", name, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (NSString *)name {
 return objc_getAssociatedObject(self, @"name");
}

 NSObject *person = [NSObject new];
 person.name = @"以夢為馬";

- (void)buttonClick:(UIButton *)sender {
 /*
  動(dòng)態(tài)添加 coding 方法
  (IMP)codingOC 意思是 codingOC 的地址指針;
  "v@:" 意思是，v 代表無返回值 void，如果是 i 則代表 int；@代表 id sel; : 代表 SEL _cmd;
  “v@:@@” 意思是，兩個(gè)參數(shù)的沒有返回值。
  */
 class_addMethod([_person class], @selector(coding), (IMP)codingOC, "v@:");
 // 調(diào)用 coding 方法響應(yīng)事件
 if ([_person respondsToSelector:@selector(coding)]) {
  [_person performSelector:@selector(coding)];
  self.testLabelText = @"添加方法成功";
 } else {
  self.testLabelText = @"添加方法失敗";
 }
}

 
// 編寫 codingOC 的實(shí)現(xiàn)
void codingOC(id self,SEL _cmd) {
 NSLog(@"添加方法成功");
}

 Method oriMethod = class_getInstanceMethod(_person.class, @selector(coding));
 Method curMethod = class_getInstanceMethod(_person.class, @selector(eating));
 method_exchangeImplementations(oriMethod, curMethod);

 _person = [NNPerson new];
 _library = [NNLibrary new];
 self.testLabelText = [_library libraryMethod];
 Method oriMethod = class_getInstanceMethod(_person.class, @selector(changeMethod));
 Method curMethod = class_getInstanceMethod(_library.class, @selector(libraryMethod));
 method_exchangeImplementations(oriMethod, curMethod);

+ (void)load {
 static dispatch_once_t onceToken;
 dispatch_once(&onceToken, ^{
  Method oriMethod = class_getInstanceMethod(self.class, @selector(sendAction:to:forEvent:));
  Method cusMethod = class_getInstanceMethod(self.class, @selector(customSendAction:to:forEvent:));
  // 判斷自定義的方法是否實(shí)現(xiàn), 避免崩潰
  BOOL addSuccess = class_addMethod(self.class, @selector(sendAction:to:forEvent:), method_getImplementation(cusMethod), method_getTypeEncoding(cusMethod));
  if (addSuccess) {
   // 沒有實(shí)現(xiàn), 將源方法的實(shí)現(xiàn)替換到交換方法的實(shí)現(xiàn)
   class_replaceMethod(self.class, @selector(customSendAction:to:forEvent:), method_getImplementation(oriMethod), method_getTypeEncoding(oriMethod));
  } else {
   // 已經(jīng)實(shí)現(xiàn), 直接交換方法
   method_exchangeImplementations(oriMethod, cusMethod);
  }
 });
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
 unsigned int count = 0;
 // 獲取類中所有屬性
 Ivar *ivars = class_copyIvarList(self.class, &count);
 // 遍歷屬性
 for (int i = 0; i < count; i ++) {
  // 取出 i 位置對應(yīng)的屬性
  Ivar ivar = ivars[i];
  // 查看屬性
  const char *name = ivar_getName(ivar);
  NSString *key = [NSString stringWithUTF8String:name];
  // 利用 KVC 進(jìn)行取值，根據(jù)屬性名稱獲取對應(yīng)的值
  id value = [self valueForKey:key];
  [aCoder encodeObject:value forKey:key];
 }
 free(ivars);
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {
 if (self = [super init]) {
  unsigned int count = 0;
  // 獲取類中所有屬性
  Ivar *ivars = class_copyIvarList(self.class, &count);
  // 遍歷屬性
  for (int i = 0; i < count; i ++) {
   // 取出 i 位置對應(yīng)的屬性
   Ivar ivar = ivars[i];
   // 查看屬性
   const char *name = ivar_getName(ivar);
   NSString *key = [NSString stringWithUTF8String:name];
   // 進(jìn)行解檔取值
   id value = [aDecoder decodeObjectForKey:key];
   // 利用 KVC 對屬性賦值
   [self setValue:value forKey:key];
  }
 }
 return self;
}

/** 字典轉(zhuǎn)模型 **/
+ (instancetype)modelWithDict:(NSDictionary *)dict {
 id objc = [[self alloc] init];
 unsigned int count = 0;
 // 獲取成員屬性數(shù)組
 Ivar *ivarList = class_copyIvarList(self, &count);
 // 遍歷所有的成員屬性名
 for (int i = 0; i < count; i ++) {
  // 獲取成員屬性
  Ivar ivar = ivarList[i];
  // 獲取成員屬性名
  NSString *ivarName = [NSString stringWithUTF8String:ivar_getName(ivar)];
  NSString *key = [ivarName substringFromIndex:1];
  // 從字典中取出對應(yīng) value 給模型屬性賦值
  id value = dict[key];
  // 獲取成員屬性類型
  NSString *ivarType = [NSString stringWithUTF8String:ivar_getTypeEncoding(ivar)];
  // 判斷 value 是不是字典
  if ([value isKindOfClass:[NSDictionary class]]) {
   ivarType = [ivarType stringByReplacingOccurrencesOfString:@"@" withString:@""];
   ivarType = [ivarType stringByReplacingOccurrencesOfString:@"\"" withString:@""];
   Class modalClass = NSClassFromString(ivarType);
   // 字典轉(zhuǎn)模型
   if (modalClass) {
    // 字典轉(zhuǎn)模型
    value = [modalClass modelWithDict:value];
   }
  }
  if ([value isKindOfClass:[NSArray class]]) {
   // 判斷對應(yīng)類有沒有實(shí)現(xiàn)字典數(shù)組轉(zhuǎn)模型數(shù)組的協(xié)議
   if ([self respondsToSelector:@selector(arrayContainModelClass)]) {
    // 轉(zhuǎn)換成id類型，就能調(diào)用任何對象的方法
    id idSelf = self;
    // 獲取數(shù)組中字典對應(yīng)的模型
    NSString *type = [idSelf arrayContainModelClass][key];
    // 生成模型
    Class classModel = NSClassFromString(type);
    NSMutableArray *arrM = [NSMutableArray array];
    // 遍歷字典數(shù)組，生成模型數(shù)組
    for (NSDictionary *dict in value) {
     // 字典轉(zhuǎn)模型
     id model = [classModel modelWithDict:dict];
     [arrM addObject:model];
    }
    // 把模型數(shù)組賦值給value
    value = arrM;
   }
  }
  // KVC 字典轉(zhuǎn)模型
  if (value) {
   [objc setValue:value forKey:key];
  }
 }
 return objc;
}