JSON parsing using NSJSONSerialization in iOS

Question

I am parsing a JSON in my code. But I am getting some unexpected issues while retrieving data of parsed JSON. So let me explain my problem.

I have to parse following JSON data using xcode. This is what data to be parsed looks like while I hit same URL in browser:

{
"RESPONSE":[
    {"id":"20",
    "username":"john",
    "email":"[email protected]",
    "phone":"1234567890",
    "location":"31.000,71.000"}],
"STATUS":"OK",
"MESSAGE":"Here will be message"
}

My code to reach up to this JSON data is as follow:

NSData *data = [NSData dataWithContentsOfURL:finalurl];
NSError *error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

If I print object json using NSLog, i.e. NSLog(@"json: %@", [json description]); it looks like:

json: {
    MESSAGE = "Here will be message";
    RESPONSE =(
                {
            email = "[email protected]";
            id = 20;
            location = "31.000,71.000";
            phone = 1234567890;
            username = john;
        }
    );
    STATUS = OK;
}

So, here I observed two things:

Sequence of keys (or nodes) (MESSAGE, RESPONSE and STATUS) is changed as compared to web response above.
The RESPONSE is get enclosed in '(' & ')' braces.

Now if I separate out values for keys MESSAGE & STATUS and NsLog them, then they get printed as proper string.

Like msgStr:Here will be message & Status:OK

But if I separate out value for RESPONSE as a dictionary and again separating sub values of that dictionary like email and username, then I can't getting those as string.

Here is the code so far I wrote:

NSMutableDictionary *response = [json valueForKey:@"RESPONSE"];
NSString *username = [response valueForKey:@"username"];
NSString *emailId = [response valueForKey:@"email"];

If I print username and emailId, then they are not getting printed as normal string, instead it outputs as:

username:(
    john
)

email:(
    [email protected]
)

So my question is why it's not getting as a normal string? If I tried to use this variables further then they show value enclosed within '(' & ')' braces. Is this happening because of NSJSONSerialization?

Formatting is changed because of now it is NSDictionary instead of formatted JSON string. NSDictionary has own format for printing its description — NeverBe
– NeverBe, Commented Dec 5, 2013 at 11:46

Suryakant Sharma · Accepted Answer · 2013-12-05 12:01:18Z

7

First of all in your JSON response dictionary, under the key 'RESPONSE' you have a array not a dictionary and that array contains dictionary object. So to extract username and email ID so as below

NSMutableDictionary *response = [[[json valueForKey:@"RESPONSE"] objectAtIndex:0]mutableCopy];
 NSString *username = [response valueForKey:@"username"];
 NSString *emailId = [response valueForKey:@"email"];

edited Dec 5, 2013 at 12:01

answered Dec 5, 2013 at 11:52

Suryakant Sharma

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1 Comment

neilco Over a year ago

[[json valueForKey:@"RESPONSE"] objectAtIndex:0]; is not mutable unless you request the mutableCopy like so: [[[json valueForKey:@"RESPONSE"] objectAtIndex:0] mutableCopy];

Chris · Accepted Answer · 2013-12-05 11:52:17Z

When you see braces like that, it represents an array, not a dictionary. Your JSON also shows that by enclosing the data in brackets ('[' and ']'). So:

RESPONSE =(
                {
            email = "[email protected]";
            id = 20;
            location = "31.000,71.000";
            phone = 1234567890;
            username = john;
        }
);

RESPONSE is an Array of Dictionaries. To access the data, iterate through the array:

for (NSDictionary *responseDictionary in [JSONDictionary objectForKey:@"RESPONSE"]) {
        NSString *name = [responseDictionary objectForKey:@"username"];
        .....
}

or grab a dictionary at an index:

NSDictionary *responseDictionary = [[JSONDictionary objectForKey:@"RESPONSE"] objectAtIndex:0];
NSString *name = [responseDictionary objectForKey:@"username"];

Whenever in doubt, log the the class:

NSLog(@"%@", [[dictionary objectForKey:@"key"] class]);

to see what is being returned from the dictionary.

Anoop Vaidya · Accepted Answer · 2013-12-05 11:54:44Z

3

1)Sequence of keys (or nodes) (MESSAGE, RESPONSE and STATUS) is changed as compared to web response above.

The NSLog of NSDictionary is based on the sorted keys.

2)The RESPONSE is get enclosed in '(' & ')' braces.

RESPONSE =(
            {
        email = "[email protected]";
        id = 20;
        location = "31.000,71.000";
        phone = 1234567890;
        username = john;
    }
);

The RESPONSE is a key and the value is an NSArray. The array contains one NSDictionary object with keys as email, id, location, phone and username.

NOTE: () says array. {} says dictionary.

answered Dec 5, 2013 at 11:54

Anoop Vaidya

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1 Comment

Nayan Over a year ago

hey thanks bro, for clearing my theoretical concept. Hence +1, But suryakant's ans worked for me practically.

Midhun MP · Accepted Answer · 2013-12-05 11:52:29Z

2

RESPONSE contains an array not an object.

So try like this:

NSMutableArray *response = [json valueForKey:@"RESPONSE"];
NSString *username = [[response objectAtIndex:0] valueForKey:@"username"];
NSString *emailId  = [[response objectAtIndex:0] valueForKey:@"email"];
NSLog(@"User=>[%@] Pwd=>[%@]",username ,emailId );

answered Dec 5, 2013 at 11:52

Midhun MP

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3 Comments

neilco Over a year ago

[json valueForKey:@"RESPONSE"]; is not mutable unless you request the mutableCopy like so: [[json valueForKey:@"RESPONSE"] mutableCopy];

Midhun MP Over a year ago

@neilco: I just saw your comment (After 3 years). Can you tell me what is the importance of mutableCopy in this context ?

neilco Over a year ago

@midhun: In your answer you specified: NSMutableArray *response = [json valueForKey:@"RESPONSE"]; but valueForKey: only returns immutable objects so response is actually an instance of NSArray, not NSMutableArray. If you want response to be mutable, you need to call mutableCopy on the return value of valueForKey:.

Community · Accepted Answer · 2020-06-20 09:12:55Z

pragma mark - Checking Reachability and Parsing Datas

NSString *urlString = [NSString stringWithFormat: @"https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=11.021459,76.916332&radius=2000&types=atm&sensor=false&key=AIzaSyD7c1IID7zDCdcfpC69fC7CUqLjz50mcls"];
NSURL *url = [NSURL URLWithString: urlString];
NSData *data = [NSData dataWithContentsOfURL:url];
NSDictionary *jsonData = [NSJSONSerialization JSONObjectWithData: data options: 0 error: nil];
array = [[NSMutableArray alloc]init];
array = [[jsonData objectForKey:@"results"] mutableCopy];
[jsonTableview reloadData];}

pragma mark- UITableView Delegate

  - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

return 1;
 }

 - (NSInteger)tableView:(UITableView *)tableView          
 numberOfRowsInSection:(NSInteger)section {

return array.count;
  }

 - (UITableViewCell *)tableView:(UITableView *)tableView    
 cellForRowAtIndexPath:(NSIndexPath *)indexPath {

  static NSString *cellid = @"cell";
UITableViewCell *cell = [tableView       
 dequeueReusableCellWithIdentifier:cellid];
cell = [[UITableViewCell   
 alloc]initWithStyle:UITableViewCellStyleSubtitle    
  reuseIdentifier:cellid];

cell.textLabel.text = [[array    
 valueForKeyPath:@"name"]objectAtIndex:indexPath.row];
cell.detailTextLabel.text = [[array 
valueForKeyPath:@"vicinity"]objectAtIndex:indexPath.row];
NSURL *imgUrl = [NSURL URLWithString:[[array 
valueForKey:@"icon"]objectAtIndex:indexPath.row]];
NSData *imgData = [NSData dataWithContentsOfURL:imgUrl];
cell.imageView.layer.cornerRadius =        
 cell.imageView.frame.size.width/2;
cell.imageView.layer.masksToBounds = YES;
cell.imageView.image = [UIImage imageWithData:imgData];

return cell;
 }

#import.h

@interface JsonViewController :     
UIViewController<UITableViewDelegate,UITableViewDataSource>
@property (weak, nonatomic) IBOutlet UITableView *jsonTableview;
@property (weak, nonatomic) IBOutlet UIBarButtonItem *barButton;
@property (strong,nonatomic)NSArray *array;
@property NSInteger select;

Answering with codes only is not a good reply. Please read this how-to-answer for providing quality answer.

Shob-Z · Accepted Answer · 2013-12-05 11:53:04Z

-2

By serializing the data, u get a json object. Json object and dictionary are different a bit.

Instead of using:

NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

use:

NSDictionary    *json    =   (NSDictionary*) data;

answered Dec 5, 2013 at 11:53

Shob-Z

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2 Comments

neilco Over a year ago

This does not answer the question at all. JSONObjectWithData:options:error: takes the NSData representation of a JSON string and deserialises it into either NSArray or NSDictionary.

gnasher729 Over a year ago

JSON object and NSDictionary are equivalent. The JSON documentation calls it "object", but the JSON documentation applies to all implementations, not just an iOS one. In iOS, "array"s are stored as NSArray*, "object"s are stored as NSDictionary*, "string"s as NSString*, bool, integer and number as NSNumber*. And casting data, which has type NSData*, to NSDictionary* isn't going to do anything useful.

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