Dealing with JSON in IOS

Question

im really new to IOS development. i am developing an application which is getting data from a web service. i am using a method which will call the service and get the response. actually im getting my response as a string. but im converted it into NsData type variable. im referring this code

 NSError* error;
NSDictionary* json = [NSJSONSerialization 
    JSONObjectWithData:responseData //1

    options:kNilOptions 
    error:&error];

NSArray* latestLoans = [json objectForKey:@"loans"]; //2
NSDictionary* loan = [latestLoans objectAtIndex:0];


NSNumber* fundedAmount = [loan objectForKey:@"funded_amount"];
NSNumber* loanAmount = [loan objectForKey:@"loan_amount"];
float outstandingAmount = [loanAmount floatValue] - 
[fundedAmount floatValue];


humanReadble.text = [NSString stringWithFormat:@"Latest loan: %@ 
from %@ needs another $%.2f to pursue their entrepreneural dream",
[loan objectForKey:@"name"],
[(NSDictionary*)[loan objectForKey:@"location"] 
objectForKey:@"country"],
outstandingAmount];

but in my case, my code segment gives me an error in the 3rd line... which is NSDictionary* loan = [latestLoans objectAtIndex:0];

Error is: [__NSCFDictionary objectAtIndex:]: unrecognized selector sent to instance 0xa959a60

my response from the web service is this

{
  "d": {
    "__type": "Paragonsoft.Caregiver.WebUI.Public.Mobile.DTO.ProfileDTO",
    "PersonId": 58,
    "PersonTypeId": 2,
    "FirstName": "Aruna",
    "LastName": "Wanniarrchi",
    "Email": "sudheeraxcvb@paragonsoftlog.net",
    "Title": 0,
    "Gender": 1,
    "Phone": "(343) 123-4324",
    "MobileNo": "(423) 123-4234",
    "ImageURL": " ../images/UploadsTest/ProfileImagesLarge/CG/16/2172014220495482.jpg",
    "Age": 38,
    "MaritalStatus": null,
    "HourlyRateFrom": 25,
    "HourlyRateTo": 35,
    "CaringHours": null,
    "Schedules": "Reliever, On Call, Regular",
    "Languages": "English, Cantonese, Other",
    "MedicalEquips": "Hoyer Lift, Walker, Wheelchair",
    "Street": "Test Streetaa",
    "City": "Los Angeles",
    "Code": "CA",
    "ZipCode": "90078"
  }
}

Below is my code

NSString* user = self.userName.text;
NSString* password = self.passWord.text;

NSArray* values = [NSArray arrayWithObjects:user,password, nil];
NSArray* keys = [NSArray arrayWithObjects:@"username",@"password", nil];
NSString* urls = [NSString stringWithFormat:@"myUrl"];

jsonpaser *jp = [[jsonpaser alloc]init];
NSString* result =  [jp getjsonFromURltest:urls :keys :values];

//convert the result string to nsData
NSData* result_data = [result dataUsingEncoding:NSUTF8StringEncoding];

NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:result_data options:kNilOptions error:&error];
NSArray* jsonrespond = [json objectForKey:@"d"]; //2

NSLog(@"Result: %@", jsonrespond);
NSDictionary* userDetails = [jsonrespond objectAtIndex:0]; // this is the point i got error

// i want to read some specific item from my response
NSString* userId = [userDetails objectForKey:@"PersonId"];

I guess I'm getting dictionary as a array..but i dont know how to fix it.

Answer 1

You are trying to fetch the dictionary data as array. Try this

NSDictionary* json = [NSJSONSerialization JSONObjectWithData:result_data 
                                                     options:kNilOptions 
                                                       error:&error];
NSDictionary* jsonrespond = [json objectForKey:@"d"]; //2
NSLog(@"Result: %@", jsonrespond);

if (jsonrespond) {
    NSString* userId = [jsonrespond objectForKey:@"PersonId"];
}

you are getting error in NSDictionary* loan = [latestLoans objectAtIndex:0]; because you are trying get elements using objectAtIndex from dictionary. Since the latestLoans is dictionary it throws you error. Its not an array.

Answer 2

the "loans" field is not available in web service, so you cant access it...

NSArray* latestLoans = [json objectForKey:@"loans"]

instead of.....

NSArray* latestLoans = [json objectForKey:@"__type"];

You get it.., The "__type" is the field of web service so you can get it...