runtime-API

1.遍历类的属性

// 更改类属性值
- (void)sayName
{
 unsigned int count = 0;
 Ivar *ivar = class_copyIvarList([self.person class], &count);
 
 for (int i = 0; i<count; i++) {
 Ivar var = ivar[i];
 const char *varName = ivar_getName(var);
 NSString *proname = [NSString stringWithUTF8String:varName];
 
 if ([proname isEqualToString:@"_name"]) { //这里别忘了给属性加下划线
 object_setIvar(self.person, var, @"daming");
 break;
 }
 }
 NSLog(@"XiaoMing change name is %@",self.person.name);
 self.textfield.text = self.person.name;
}

2.动态创建方法

- (void)sayFrom
{
 
 class_addMethod([self.person class], @selector(guess), (IMP)guessAnswer, "v@:");
 if ([self.person respondsToSelector:@selector(guess)]) {
 //Method method = class_getInstanceMethod([self.xiaoMing class], @selector(guess));
 [self.person performSelector:@selector(guess)];
 
 } else{
 NSLog(@"Sorry,I don't know");
 }
 self.textview.text = @"beijing";
}
void guessAnswer(id self,SEL _cmd){
 
 NSLog(@"i am from beijing");
 
}

3.动态交换两个方法

 Method m1 = class_getInstanceMethod([self.person class], @selector(sayName));
 Method m2 = class_getInstanceMethod([self.person class], @selector(saySex));
 
 method_exchangeImplementations(m1, m2);

4.在一个类运行的时候,动态的替换掉该类的方法

 Method m1 = class_getInstanceMethod([Person class], @selector(sayName));
 Method m2 = class_getInstanceMethod([Tool class], @selector(changeMethod));
 
 method_exchangeImplementations(m1, m2);

5.实现归档和反归档

// 字典转模型
+ (instancetype)objectWithDict:(NSDictionary *)dict
{
 // 创建对应模型对象
 id objc = [[self alloc] init];
 
 
 unsigned int count = 0;
 
 // 1.获取成员属性数组
 Ivar *ivarList = class_copyIvarList(self, &count);
 
 // 2.遍历所有的成员属性名,一个一个去字典中取出对应的value给模型属性赋值
 for (int i = 0; i < count; i++) {
 
 // 2.1 获取成员属性
 Ivar ivar = ivarList[i];
 
 // 2.2 获取成员属性名 C -> OC 字符串
 NSString *ivarName = [NSString stringWithUTF8String:ivar_getName(ivar)];
 
 // 2.3 _成员属性名 => 字典key
 NSString *key = [ivarName substringFromIndex:1];
 
 // 2.4 去字典中取出对应value给模型属性赋值
 id value = dict[key];
 
 
 // 获取成员属性类型
 NSString *ivarType = [NSString stringWithUTF8String:ivar_getTypeEncoding(ivar)];
 
 // 二级转换,字典中还有字典,也需要把对应字典转换成模型
 //
 // 判断下value,是不是字典
 if ([value isKindOfClass:[NSDictionary class]] && ![ivarType containsString:@"NS"]) { // 是字典对象,并且属性名对应类型是自定义类型
 // user User
 
 // 处理类型字符串 @\"User\" -> User
 ivarType = [ivarType stringByReplacingOccurrencesOfString:@"@" withString:@""];
 ivarType = [ivarType stringByReplacingOccurrencesOfString:@"\"" withString:@""];
 // 自定义对象,并且值是字典
 // value:user字典 -> User模型
 // 获取模型(user)类对象
 Class modalClass = NSClassFromString(ivarType);
 
 // 字典转模型
 if (modalClass) {
 // 字典转模型 user
 value = [modalClass objectWithDict:value];
 }
 
 // 字典,user
 // NSLog(@"%@",key);
 }
 
 // 三级转换:NSArray中也是字典,把数组中的字典转换成模型.
 // 判断值是否是数组
 if ([value isKindOfClass:[NSArray class]]) {
 // 判断对应类有没有实现字典数组转模型数组的协议
 if ([self respondsToSelector:@selector(arrayContainModelClass)]) {
 
 // 转换成id类型,就能调用任何对象的方法
 id idSelf = self;
 
 // 获取数组中字典对应的模型
 NSString *type = [idSelf arrayContainModelClass][key];
 
 // 生成模型
 Class classModel = NSClassFromString(type);
 NSMutableArray *arrM = [NSMutableArray array];
 // 遍历字典数组,生成模型数组
 for (NSDictionary *dict in value) {
 // 字典转模型
 id model = [classModel objectWithDict:dict];
 [arrM addObject:model];
 }
 
 // 把模型数组赋值给value
 value = arrM;
 
 }
 }
 
 // 2.5 KVC字典转模型
 if (value) {
 
 [objc setValue:value forKey:key];
 }
 }
 
 
 // 返回对象
 return objc;
 
}
归档
- (void)encodeWithCoder:(NSCoder *)encoder
{
 unsigned int count = 0;
 
 Ivar *ivars = class_copyIvarList([Movie class], &count);
 
 for (int i = 0; i<count; i++) {
 // 取出i位置对应的成员变量
 Ivar ivar = ivars[i];
 // 查看成员变量
 
 const char *name = ivar_getName(ivar);
 // 归档
 NSString *key = [NSString stringWithUTF8String:name];
 id value = [self valueForKey:key];
 [encoder encodeObject:value forKey:key];
 
 }
 
 free(ivars);
 
 
}
反归档
- (id)initWithCoder:(NSCoder *)decoder
{
 if (self = [super init]) {
 unsigned int count = 0;
 Ivar *ivars = class_copyIvarList([Movie class], &count);
 for (int i = 0; i<count; i++) {
 // 取出i位置对应的成员变量
 Ivar ivar = ivars[i];
 // 查看成员变量
 const char *name = ivar_getName(ivar);
 // 归档
 NSString *key = [NSString stringWithUTF8String:name];
 id value = [decoder decodeObjectForKey:key];
 // 设置到成员变量身上
 [self setValue:value forKey:key];
 
 }
 free(ivars);
 
 }
 
 return self;
 
}