索引到数组字典时无法识别选择器错误 [英] Unrecognized selector error when indexing into a dictionary of arrays

问题描述

我有一个数组字典导致 __ NSCFDictionary objectAtIndex：错误。

I have a dictionary of arrays that is causing __NSCFDictionary objectAtIndex: errors.

有人可以告诉我为什么？字典显然在出错时至少有一个数组。

Can someone tell me why? The dictionary clearly has at least 1 array at the time of the error.

 NSError *error;
 responseString = [[NSString alloc] initWithData:self.responseData2 encoding:NSUTF8StringEncoding];

/* response string contains this:
   {"words":
     {
    "word": {"rowsreturned":0,"id":"-1","date":"","word":"","term":"","definition":"","updated_on":""}
     },
    "status":"",
    "rowsreturned":""
  }
*/

 NSDictionary *json = [NSJSONSerialization JSONObjectWithData:self.responseData2 options:kNilOptions error:&error];

 NSArray *todaysWord = [[json objectForKey:@"words"] objectForKey:@"word"];

 //error here -[__NSCFDictionary objectAtIndex:]: unrecognized selector sent to instance
 NSDictionary *word = [todaysWord objectAtIndex:0];

推荐答案

在您的情况下 [[ json objectForKey：@words] objectForKey：@word]; 返回字典而不是数组。尝试执行以下操作，

In your case [[json objectForKey:@"words"] objectForKey:@"word"]; is returning a dictionary and not an array. Try doing the following,

id wordParam = [[json objectForKey:@"words"] objectForKey:@"word"];

if ([wordParam isKindOfClass:[NSArray class]]) {
  NSDictionary *word = [(NSArray *)wordParam objectAtIndex:0];
} else if ([wordParam isKindOfClass:[NSDictionary class]]) {
  NSDictionary *word = (NSDictionary *)wordParam;
} else {
  NSLog(@"error. %@ is not an array or dictionary", wordParam);
}

您的回复字符串还显示 word <的值/ code>是，

Your response string also shows that value for word is,

{"rowsreturned":0,"id":"-1","date":"","word":"","term":"","definition":"","updated_on":""}

这是一个字典，键值对为 rowsreturned：0 ， id：-1 等..

which is a dictionary with key value pairs as rowsreturned:0, id:-1 etc..

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