How to fetch elements from NSArray in Objective C - ios

Question

I'm using a bus timetable API and want to display the nearby bus stop according to user current location. I've already got the the JSON response through url and parsed JSON to NSArray. The NSArray looks like this.
{
result = {
distance = "0.00003292029";
lat = "-37.92091";
"location_name" = "Monash Medical Centre/Clayton Rd ";
lon = "145.120682";
"route_type" = 2;
"stop_id" = 16518;
suburb = Clayton;
"transport_type" = bus;
};
type = stop;
},
{
result = {
distance = "0.00003728643";
lat = "-37.92227";
"location_name" = "Monash Surgical Private Hospital/291 Clayton Rd ";
lon = "145.1202";
"route_type" = 2;
"stop_id" = 24348;
suburb = Clayton;
"transport_type" = bus;
};
type = stop;
},
{
result = {
distance = "0.00003804303";
lat = "-37.9230766";
"location_name" = "Clayton Railway Station/Clayton Rd ";
lon = "145.120209";
"route_type" = 2;
"stop_id" = 22809;
suburb = Clayton;
"transport_type" = bus;
};
type = stop;
},
{
result = {
distance = "0.00003976311";
lat = "-37.9186172";
"location_name" = "Monash Specialist Centre/Clayton Rd ";
lon = "145.121033";
"route_type" = 2;
"stop_id" = 22807;
suburb = Clayton;
"transport_type" = bus;
};
type = stop;
},
{
result = {
distance = "0.00004085229";
lat = "-37.9186478";
"location_name" = "Dixon St/Clayton Rd ";
lon = "145.120911";
"route_type" = 2;
"stop_id" = 13889;
suburb = Clayton;
"transport_type" = bus;
};
type = stop;
}
)
My question is how to get the latitude and longitude from this NSArray. I wrote these code but it returns nil.
NSMutableArray *coordinateLatit = [[NSMutableArray alloc]init];
for (int i = 0; i<nearbyStop.count; i++) {
NSString *latit = [[nearbyStop objectAtIndex:1] objectForKey:#"lat"];
if(latit == nil)
{
NSLog(#"there is no data");
}
else
{
[coordinateLatit addObject:latit];
}
}
And also i want to display the stops(use longitude&latitude from NSArray) on MKMapView, how should i manage to implement the MKLocalSearchRequest
Appreciate it if anyone can help me!

Answer 1

Your code overlooked the extra nested result level.
NSMutableArray *coordinateLatit=[[NSMutableArray alloc]init];
for(NSDictionary *d in nearbyStop)
{
NSString *latit=d[#"result"][#"lat"];
if(lat) [coordinateLatit addObject:latit];
}

Answer 2

-(id) doApiCall:(NSString*)apiCall useCache:(BOOL)useCache
{
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:#"%#%#", mBaseURL, [MapViewController signApiCall:apiCall]]];
id response = [self httpWrapper:url];
NSLog( #"%#", response );
return response;
}
-(id) httpWrapper:(NSURL*)url
{
__block id response = nil;
void (^doStuff)() = ^void()
{
int retry = 3;
NSError * error;
while( retry > 0) {
NSData * data = [NSURLConnection sendSynchronousRequest:[NSURLRequest requestWithURL:url
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:600] returningResponse:nil error:&error ];
if( data != nil )
{
response = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
if( response != nil)
retry = 0;
}
if(data == nil || response == nil)
{
NSLog(#"Bad response %#", url);
NSLog(#"%#", error);
--retry;
}
}
};
doStuff();
return response;
}
-(NSArray*) nearby:(CLLocation*)location
{
return [self doApiCall:[NSString stringWithFormat:#"/v2/nearme/latitude/%f/longitude/%f?limit=5", location.coordinate.latitude, location.coordinate.longitude]];
}
Here is the code i'm using to call the API. I use id for the response from url request. so does nearby method returns NSArray type?

Answer 3

you miss a level of the json response, it should be
for (Stop *stop in nearbyStop) {
NSString *latit = [[stop objectForKey:#"result"] objectForKey:#"lat"];
if(latit == nil)
{
NSLog(#"there is no data");
}
else
{
[coordinateLatit addObject:latit];
}
}