JSON parsing using ios

Question

I use the following code

NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:response 
                                                     options:NSJSONReadingAllowFragments                                                           
                                                       error:&err];

first I want to add 2 options NSJSONReadingAllowFragments, and NSJSONReadingMutableContainers

if I used only NSJSONReadingMutableContainers the code will crash

now if the response is just string true or false , how to compare the value of NSArray to string "false" for example

I cannot say for example [jsonArray objectatindex:0]

any idea how to make my code intellegent enough such that if only the response is array of object or only string

You can check length of array for this. If length is 1 then again check value of array at index 0 for true/false. — aks.knit1108, Feb 16 '13 at 13:08
First check if `jsonArray` is nil. If it is check the `err`. Chances are the `response` is invalid, NSLog `response` and insure it is valid json. Basic debugging, check the inputs. — zaph, Feb 16 '13 at 13:16
it's not nil , it's just contain the false string , but am not sure how to check it , I cannot say objectatindexof , or count , .... — AMH, Feb 16 '13 at 13:19
Check `jsonArray` with `NSLog`. To find the class of `jsonArray`: `NSLog(@"class type: %@", NSStringFromClass([jsonArray class]);` — zaph, Feb 16 '13 at 13:22
Take a look on http://stackoverflow.com/questions/8356842/how-to-use-nsjsonserialization — aks.knit1108, Feb 16 '13 at 13:24
As I told in my example first check class type and if it is NSString type, then it means your string is true or false. — aks.knit1108, Feb 16 '13 at 13:27
`NSJSONReadingAllowFragments` is not a valid option for `JSONObjectWithData` when you expect an `NSArray`. Apple docs: NSJSONReadingAllowFragments Specifies that the parser should allow top-level objects that are not an instance of NSArray or NSDictionary. — zaph, Feb 16 '13 at 13:27
@Zaph the class is class type: __NSCFString how to extract the string within it , there is no isequaltostring — AMH, Feb 16 '13 at 13:36
`NSJSONReadingAllowFragments` is not valid for a return type of `NSArray` or `NSDictionary`. — zaph, Feb 16 '13 at 13:48

aks.knit1108 · Accepted Answer · 2013-02-16T13:34:54.127

1

Before working on response check Class type.

id jsonObject = [NSJSONSerialization JSONObjectWithData:response 
                                                 options:NSJSONReadingAllowFragments                                                           
                                                   error:&err];

if ([jsonObject isKindOfClass:[NSArray class]]) {
    // Do stuff for array.
}
else if ([jsonObject isKindOfClass:[NSDictionary class]]) {
   // Do stuff for dictionary
}

else if ([jsonObject isKindOfClass:[NSString class]]) {
   // Do stuff for string
}

edited Feb 16 '13 at 13:34

answered Feb 16 '13 at 13:18

aks.knit1108

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what do u mean by the jsonData , is it the jsonArray , also how to add multiple options – AMH Feb 16 '13 at 13:26
see my edit. jsonArray is like jsonObject and I have change djsonData with response – aks.knit1108 Feb 16 '13 at 13:35
it's type of __NSCFString how to extract the data of it I mean I cannot say isequal to string or any other data – AMH Feb 16 '13 at 13:39
By placing above code in which block your control goes, during debugging check it and tell me – aks.knit1108 Feb 16 '13 at 13:44
thanks a lot it work very well , I will test against dictionary and Nssarray – AMH Feb 16 '13 at 13:55
am sorry but will the option NSJSONReadingAllowFragments will read dictionary or nssarray – AMH Feb 16 '13 at 14:00
If you are facing problem then you can use NilOption for the same. Because I am not sure about NSJSONReadingAllowFragments. Because I never tested it on my end. – aks.knit1108 Feb 16 '13 at 14:19
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/24621/discussion-between-best-coder-and-amh) – aks.knit1108 Feb 16 '13 at 14:23

score 0 · Answer 2 · answered Feb 16 '13 at 13:42

The returned JSON is a fragment that is an NSString, count is not valid for strings. Change the return type:

NSString *jsonString = [NSJSONSerialization JSONObjectWithData:response 
                                                     options:NSJSONReadingAllowFragments                                                           
                                                       error:&err];

NSLog(@"jsonArray: %@, length: %d", jsonString, jsonString.length);

Then do whatever you want with the string.

Generally JSON is an array or a dictionary, in this case it is a string, possibly the JSON is not correctly formatted.

JSON parsing using ios

2 Answers2