Question

是否有人对未知结构的NSDictionary进行了递归有序遍历？我想采用任何NSDictionary并按层次顺序处理每个级别。

1）此数据来自经过验证的JSON。可以肯定地说，从SBJSON（JSON Framework）这样的框架创建的NSDictionary只会导致嵌套字典，数组和任意叶子的组合吗？

2）如何使用适用于数组和字典的快速枚举来完成泛型遍历？使用下面的代码，一旦我到达数组中的字典，它就会停止遍历。但是，如果我继续数组条件中的递归（以检查数组中的字典），它会在id value = [dict valueForKey:key];的下一次迭代中使用-[__NSCFDictionary length]: unrecognized selector sent to instance SIGABRT进行barfs。我不知道为什么这会成为一个问题，因为我已经通过一个顶级字典（其中找到了子级字典数组）超过了该行。

-(void)processParsedObject:(id)dict counter:(int)i parent:(NSString *)parent
{
    for (id key in dict) {
        id value = [dict valueForKey:key];
        NSLog(@"%i : %@ : %@ -> %@", i, [value class], parent, key);

        if ([value isKindOfClass:[NSDictionary class]])
        {
            i++;
            NSDictionary* newDict = (NSDictionary*)value;
            [self processParsedObject:newDict counter:i parent:(NSString*)key];
            i--;
        }
        else if ([value isKindOfClass:[NSArray class]])
        {
            for (id obj in value) {
                NSLog(@"Obj Type: %@", [obj class]);
            }
        }
    }
}

非常感谢

Answer 1

我做了类似的事情，我将遍历来自Web服务的JSON结构化对象，并将每个元素转换为可变版本。

- (void)processParsedObject:(id)object
{
    [self processParsedObject:object depth:0 parent:nil];
}

- (void)processParsedObject:(id)object depth:(int)depth parent:(id)parent
{      
    if ([object isKindOfClass:[NSDictionary class]])
    {
        for (NSString* key in [object allKeys])
        {
            id child = [object objectForKey:key];
            [self processParsedObject:child depth:(depth + 1) parent:object];
        }
    }
    else if ([object isKindOfClass:[NSArray class]])
    {
        for (id child in object)
        {
            [self processParsedObject:child depth:(depth + 1) parent:object];
        }   
    }
    else
    {
        // This object is not a container you might be interested in it's value
        NSLog(@"Node: %@  depth: %d", [object description], depth);
    }
}

Answer 2

我需要知道这些值的关键名称，所以我重新写了Joel的内容并想出了这个：

- (void)enumerateJSONToFindKeys:(id)object forKeyNamed:(NSString *)keyName
{
    if ([object isKindOfClass:[NSDictionary class]])
    {
        // If it's a dictionary, enumerate it and pass in each key value to check
        [object enumerateKeysAndObjectsUsingBlock:^(id key, id value, BOOL *stop) {
            [self enumerateJSONToFindKeys:value forKeyNamed:key];
        }];
    }
    else if ([object isKindOfClass:[NSArray class]])
    {
        // If it's an array, pass in the objects of the array to check
        [object enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
            [self enumerateJSONToFindKeys:obj forKeyNamed:nil];
        }];
    }
    else
    {
        // If we got here (i.e. it's not a dictionary or array) so its a key/value that we needed 
        NSLog(@"We found key %@ with value %@", keyName, object);
    }
}

然后你会这样称呼：

[self enumerateJSONToFindKeys:JSON forKeyNamed:nil];

或者，如果您想使给定的密钥路径可变（因此您可以使用setValue:forKeyPath:回写它），您可以执行以下操作：

- (void)makeDictionariesMutableForKeyPath:(NSString *)keyPath {
    NSArray *keys = [keyPath componentsSeparatedByString:@"."];

    NSString *currentKeyPath = nil;
    for (NSString *key in keys) {
        if (currentKeyPath) {
            NSString *nextKeyPathAddition = [NSString stringWithFormat:@".%@", key];
            currentKeyPath = [currentKeyPath stringByAppendingString:nextKeyPathAddition];
        } else {
            currentKeyPath = key;
        }

        id value = [self.mutableDictionary valueForKeyPath:currentKeyPath];
        if ([value isKindOfClass:NSDictionary.class]) {
            NSMutableDictionary *mutableCopy = [(NSDictionary *)value mutableCopy];
            [self.mutableDictionary setValue:mutableCopy forKeyPath:currentKeyPath];
        }
    }

}

递归遍历未知结构的NSDictionary

2 个答案: