JSON array for picker view iPhone - iphone

Question

I am getting this data from JSON web services
List ARRAY: (
{
assets = (
{
identity = 34DL3611;
systemId = 544507;
},
{
identity = 34GF0512;
systemId = 5290211;
},
{
identity = 34HH1734;
systemId = 111463609;
},
{
identity = 34HH1736;
systemId = 111463622;
},
{
identity = 34YCJ15;
systemId = 294151155;
}
);
identity = DEMO;
systemId = 4921244;
})
By using this code:
NSArray *list =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSLog(#"Response data: %#", responseString);
NSLog(#"List ARRAY: %#", list);
NSDictionary *dict = [list objectAtIndex: 0];
NSMutableArray *vehicleGroups = [dict objectForKey:#"identity"];
NSLog(#"Vehicle Groups: %#", vehicleGroups);
Here is the picker code I am using:
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent :(NSInteger)component {
return [vehicleGroups count];}
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{return nil;}
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
}
The application crashes at the line
return [vehicleGroups count];
delegate method numberOfRowsInComponent of pickerView. I am not getting that - why I am facing this issue?
//Code////
NSArray *list =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSLog(#"Response data: %#", responseString);
NSLog(#"List ARRAY: %#", list);
NSDictionary *dict = [list objectAtIndex: 0];
vehicleList = [dict objectForKey: #"assets"];
self.vehicleGroups = [[NSMutableArray alloc] init];
vehicleGroups = [dict objectForKey:#"identity"];
NSLog(#"Vehicle Groups: %#", vehicleGroups);
NSString *identity = [dict objectForKey: #"identity"];
NSString *systemid = [dict objectForKey:#"systemId"];
self.listVehicles = [[NSMutableArray alloc] init];
self.listVehiclesID =[[NSMutableArray alloc]init];
NSLog(#"GroupOfVehicles: %#", groupOfVehicles);
for (NSUInteger index = 0; index < [vehicleList count]; index++) {
itemDict = [vehicleList objectAtIndex: index];
[self.listVehicles addObject:[itemDict objectForKey:#"identity"]];
[self.listVehiclesID addObject:[itemDict objectForKey:#"systemId"]];
}
NSLog(#"Group Name: %#", identity);
NSLog(#"Assets: %#", listVehicles);
NSLog(#"Assets System ID: %#", listVehiclesID);
NSLog(#"GroupSystemID: %#", systemid);

Answer 1

You have to initialise your array first
NSDict *list =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSLog(#"List Dict: %#", list);
NSMutableArray *temp = list[#"assets"];
NSMutableArray *vehicleGroups = [NSMutableArry array];
vehicleGroups = temp[0][#"identity"];
NSLog(#"Vehicle Groups: %#", vehicleGroups);

Answer 2

Answering my own question guide others if they face the same problem, Actually what I have done here to get the required array for identity: DEMO is as follows:
vehicleGroups =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSLog(#"Response data: %#", responseString);
NSLog(#"List ARRAY: %#", vehicleGroups);
NSDictionary *dict1 = [vehicleGroups objectAtIndex: 0];
NSString *identity1 = [dict objectForKey: #"identity"];
NSLog(#"dictNEW: %#", dict1);
groupOfVehicles = [[NSMutableArray alloc] init];
for (NSUInteger index = 0; index < [vehicleGroups count]; index++) {
itemDict = [vehicleGroups objectAtIndex: index];
[groupOfVehicles addObject:[itemDict objectForKey:#"identity"]];
}
NSLog(#"Group Name NEW: %#", identity1);
NSLog(#"Groups NEW: %#", groupOfVehicles);
After using that code I have properly got the array for my required data

Answer 3

retain the array as
[vehicleGroups retain] after vehicleGroups = [dict objectForKey:#"identity"];

Answer 4

NSDictionary *dicts = [list objectAtIndex: 0];
NSMutableArray *vehicleGroups = [[NSMutableArray alloc] init];
for (NSDictionary *dict in dicts)
{
NSString* identity = [dict objectForKey:#"identity"];
[vehicleGroups addObject:identity];
}
NSLog("count is %d",[vehicleGroups count]);
have a try :)

Answer 5

Your JSON data is not JSON.
{
"assets" : [
{
"identity" : "34DL3611",
"systemId" : 544507
},
....
{
"identity" = "34YCJ15",
"systemId" = 294151155
}
],
"identity" = "DEMO",
"systemId" = 4921244
}
This is a possible example of your data was it described in JSON.

Answer 6

NSDictionary *dict = [list objectAtIndex: 0];
NSMutableArray *vehicleGroups = [dict objectForKey:#"identity"];
It looks to me like dict here is a dictionary with three entries: assets, identity, and systemId. At this level, the value of identity is just a string, "DEMO", but you're trying to assign it to a mutable array. I think you want something like this instead:
NSDictionary *dict = [list objectAtIndex: 0];
NSArray *assets = [dict objectForKey:#"assets"];
NSArray *vehicleGroups = [assets objectForKey:#"identity"];
(It's okay to send -objectForKey: to an array -- you get back an array of objects corresponding to the given key for each object in the receiver.)