NSCFString objectAtIndex: unrecognized selector sent to instance Objective C [closed] - objective-c

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Closed 9 years ago.
I am trying to get some json data and show it as text in a UILabel but I keep on getting a app crash with the following error -[__NSCFString objectAtIndex:]: unrecognized selector sent to instance 0x1f8cfff0?
Here is my code and the json response. I see in my log that I am getting the Name from the call but the app bombs out the that error. I have 2 UILabel blocks, one of which shows a text format of the json response and the other the actual json response in text.
I'm trying to pull the name of the person, I can see Bilbo Baggins in the log when the json comes back.
Here is my json output:
{"ProfileID":34,"ProfilePictureID":20,"Name":"Bilbo Baggins","Clients":[{"ClientID":91,"Name":"Fnurky"},{"ClientID":92,"Name":"A different client"},{"ClientID":95,"Name":"Second Community"},{"ClientID":96,"Name":"Britehouse"}]}
and my code to try show it as a uilabel as text.
#define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0) //1
#define kLatestKivaLoansURL [NSURL URLWithString: #"http://www.ddproam.co.za/Central/Profile/JSONGetProfileForUser"] //2
#import "JsonViewController.h"
#interface NSDictionary(JSONCategories)
+(NSDictionary*)dictionaryWithContentsOfJSONURLString:(NSString*)urlAddress;
-(NSData*)toJSON;
#end
#implementation NSDictionary(JSONCategories)
+(NSDictionary*)dictionaryWithContentsOfJSONURLString:(NSString*)urlAddress
{
NSData* data = [NSData dataWithContentsOfURL: [NSURL URLWithString: urlAddress] ];
__autoreleasing NSError* error = nil;
id result = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
if (error != nil) return nil;
return result;
}
-(NSData*)toJSON
{
NSError* error = nil;
id result = [NSJSONSerialization dataWithJSONObject:self options:kNilOptions error:&error];
if (error != nil) return nil;
return result;
}
#end
#implementation JsonViewController
- (void)viewDidLoad
{
[super viewDidLoad];
dispatch_async(kBgQueue, ^{
NSData* data = [NSData dataWithContentsOfURL: kLatestKivaLoansURL];
[self performSelectorOnMainThread:#selector(fetchedData:) withObject:data waitUntilDone:YES];
});
}
- (void)fetchedData:(NSData *)responseData {
//parse out the json data
NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData //1
options:kNilOptions
error:&error];
NSArray* defineJsonData = [json objectForKey:#"Name"]; //2
NSLog(#"Name: %#", defineJsonData); //3
// 1) Get the latest loan
NSDictionary* loan = [defineJsonData objectAtIndex:0];
// 3) Set the label appropriately
humanReadble.text = [NSString stringWithFormat:#"Hello: %#",
[(NSDictionary*)[loan objectForKey:#"Name"] objectForKey:#"Name"]];
//build an info object and convert to json
NSDictionary* info = [NSDictionary dictionaryWithObjectsAndKeys:
[loan objectForKey:#"Name"],
nil];
//convert object to data
NSData* jsonData = [NSJSONSerialization dataWithJSONObject:info
options:NSJSONWritingPrettyPrinted
error:&error];
//print out the data contents
jsonSummary.text = [[NSString alloc] initWithData:jsonData
encoding:NSUTF8StringEncoding];
}
#end

Answer 1

A combination of – sorry – poor var names and lost in a complex structure.
First:
Here you get the complete JSON as Dictionary:
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData //1
options:kNilOptions
error:&error];
According to your Q, this has this structure:
{
"ProfileID":34,
"ProfilePictureID":20,
"Name":"Bilbo Baggins",
"Clients":
[
{
"ClientID":91,
"Name":"Fnurky"
},
{
"ClientID":92,
"Name":"A different client"
},
{
"ClientID":95,
"Name":"Second Community"
},
{
"ClientID":96,
"Name":"Britehouse"
}
]
}
Second:
With the next statement, you simply get the name of obviously something like a person:
NSArray* defineJsonData = [json objectForKey:#"Name"]; //2
There is the root:
what you get – look at your JSON – is:
"Name":"Bilbo Baggins",
You get the object for the key Name. The var, holding the reference to the result should be called expressing this. Let's change this:
NSArray* name = [json objectForKey:#"Name"]; //2
Next – look at your JSON – the object behind that key is an instance of NSString, not NSArray. Let's repair this:
NSString* name = [json objectForKey:#"Name"]; //2
Third:
Doing so will the compiler make throwing out an error. This is because of this statement:
NSDictionary* loan = [defineJsonData objectAtIndex:0];
Changed to the new var name:
NSDictionary* loan = [name objectAtIndex:0];
The compiler is right: You do not have an array, so you cannot send objectAtIndex:.