KVC

KVC
概念:Key Value Coding
作用:
1.KVC可以给对象的私有变量赋值(UIPageControl)
2.用于字典转模型(MJExtension)
3.通过KVC取出私有变量的值
4.模型对象转字典(了解)

使用注意:
1.设置key/keyPath位置的字符串必须保证有对应的属性(或者_属性)
2.字典转模型的使用注意:
1> 必须保证字典中对应key在模型中能找到对应的属性
2> 模型中的属性可以在字典中没有对应的Key

setValue:forKey:和setValue:forKeyPath区别
keyPath可以根据内部点语法,进一步查找对应的key

int main(int argc, const char * argv[]) {
@autoreleasepool {

/*
// 1.创建Person对象
Person *p = [[Person alloc] init];
p.book = [[Book alloc] init];

[p setValue:@"18" forKey:@"age"];
[p setValue:@"20" forKeyPath:@"age"];

// [p.book setValue:@"100" forKey:@"price"];
// [p.book setValue:@"200" forKeyPath:@"price"];

// [p setValue:@"300" forKey:@"book.price"];
[p setValue:@"300" forKeyPath:@"book.price"];
*/

// MJExtension
NSDictionary *dict = @{
@"name" : @"why",
@"height" : @"1.89",
@"age" : @"18",
@"weight" : @"60",
@"book" : @{@"price" : @"200"}
};

Person *p = [Person personWithDict:dict];

NSLog(@"%@", p.book);
}
return 0;
}

void notice()
{
// 1.注意一
/*
// 1.创建Person对象
Person *p = [[Person alloc] init];

// 2.给p对象的属性赋值
// [p setValue:@"20" forKeyPath:@"aga"];
*/

// 2.注意二
NSDictionary *dict = @{
@"name" : @"why",
@"height" : @"1.89",
@"age" : @"18",
@"weight" : @"60"
};
Person *p = [Person personWithDict:dict];

NSLog(@"age:%ld", p.age);
}

void getValue()
{
// 1.创建Person对象
Person *p = [[Person alloc] init];

// 2.给属性赋值
p.name = @"xiaobai";
p.age = 1;

// NSLog(@"name:%@ age:%ld height:%@", p.name, p.age, [p valueForKeyPath:@"height"]);
/*
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[dict setObject:p.name forKey:@"name"];
*/
NSDictionary *dict = [p dictionaryWithValuesForKeys:@[@"name", @"age", @"height"]];
NSLog(@"%@", dict);

// NSArray<NSString *> *array = nil;
// NSDictionary<NSString *, id> 泛型
}

void setValue()
{
/*
// 1.创建Person对象
Person *p = [[Person alloc] init];

// 2.给p属性赋值
// p.name = @"why";
[p setValue:@"lmj" forKey:@"name"];
// [p setValue:@"1.88" forKey:@"_height"];
[p setValue:@"1.88" forKeyPath:@"height"];

NSDictionary *dict = @{
@"name" : @"why",
@"height" : @"1.89",
@"age" : @"18"
};
p.name = dict[@"name"];
[p setValue:dict[@"height"] forKeyPath:@"height"];
p.age = [dict[@"age"] integerValue];
*/
// 1.定义字典
NSDictionary *dict = @{
@"name" : @"why",
@"height" : @"1.89",
@"age" : @"18"
};

// 2.字典转模型
Person *p = [Person personWithDict:dict];

NSLog(@"%@", p);
}