更改嵌套的NSMutableDictionary中的值

Question

我有一个NSMutableDictionary，我想要更改元素的值。

//My dictionary: 

{ 
    objectId = 8ED998yWd1; 
    cardInfo =  { 
     state = published; //THIS! 
     price = 40; 
     color = red; 
     } 
}; 

我尝试了好几种方法，但价值不会改变，就像这样：

[dictionary setObject:@"reserved" forKey:@"state"]; //nope 

或本：

[dictionary setValue:@"reserved" forKeyPath:@"cardInfo.state"]; //nope 

，或者：

[[dictionary objectForKey:@"cardInfo"] setObject:@"reserved" forKey:@"state"]; //no 

和这个：

[dictionary setObject:@"reserved" forKey:[[dictionary objectForKey:@"cardInfo"] objectForKey:@"state"]]; 

如何将对象“状态”从“发布”更改为“保留”？

谢谢！

Answer 1

假设都dictionary和cardInfo是NSDictionary实例：

你可以得到嵌套字典的可变复制，修改相应的值，并写入修改后的字典回“顶级”的字典，像这样：

NSMutableDictionary *mutableDict = [dictionary mutableCopy]; 
NSMutableDictionary *innerDict = [dictionary[@"cardInfo"] mutableCopy]; 
innerDict[@"state"] = @"reserved"; 
mutableDict[@"cardInfo"] = innerDict; 
dictionary = [mutableDict copy]; 

我想你可能挤在一条线，但它是一个丑陋的线。

编辑：

如果同时外部和内部字典已经mutable将事情简化了一下，当然：

NSMutableDictionary *innerDict = dictionary[@"cardInfo"]; 
innerDict[@"state"] = @"reserved"; 
dictionary[@"cardInfo"] = innerDict;