How to integrate NSUrlsession in ios - ios

Question

Hi I am very new to ios and in my app I am using NSUrlSession for integrating services.
Here my main problem is when I get a response from the server, I can't handle them properly.
When I get a correct response, then see the below json stucture:-
responseObject = {
{
Name = Broad;
DeptNo = A00;
BatchNo = 23;
DeptId = 120;
},
{
Name = James;
DeptNo = B00;
BatchNo = 23;
DeptId = 123;
},
}
when I get a wrong response, see the below json stucture:-
responseObject = {
error = 1;
message = "Invalid Code";
}
when I get a correct response from the server, I am getting an exception in my below if block(like __NSCFArray objectForKey:]: unrecognized selector sent to instance 0x1611c200') and when I get a wrong response then T get exception in my else block
Please help me how to handle them
my code:-
(void) GetCallService1: (id)MainResponse{
dispatch_async(dispatch_get_main_queue(), ^{
NameArray = [[NSMutableArray alloc]init];
IdArray = [[NSMutableArray alloc]init];
if([MainResponse objectForKey:#"error"] != nil)
{
NSLog(#"No data available");
}
else{
for (NSDictionary *obj in MainResponse) {
if([obj objectForKey:#"Name"] && [obj objectForKey:#"DeptNo"]) {
NSString * Name = [obj objectForKey:#"Name"];
[NameArray addObject:Name];
NSString * Id = [obj objectForKey:#"id"];
[IdArray addObject:Id];
}
}
}
});
}

Answer 1

1)Change Your implementation like below
2)I checked is it dictionary type & error key has some value
3)Earlier you were calling objectForKey on Array, therefore it was crashing
-(void) GetCallService1: (id)MainResponse{
dispatch_async(dispatch_get_main_queue(), ^{
NameArray = [[NSMutableArray alloc]init];
IdArray = [[NSMutableArray alloc]init];
//here I checked is it dictionary type & error key has some value
if ([MainResponse isKindOfClass:[NSDictionary class ]] &&[MainResponse objectForKey:#"error"])
{
NSLog(#"No data available");
}
else{
for (NSDictionary *obj in MainResponse) {
if([obj objectForKey:#"Name"] && [obj objectForKey:#"DeptNo"]) {
NSString * Name = [obj objectForKey:#"Name"];
[NameArray addObject:Name];
NSString * Id = [obj objectForKey:#"id"];
[IdArray addObject:Id];
}
}
}
});
}

Answer 2

Try this:
//Result Block
typedef void (^ResultBlock)(id, NSError*);
//URL request
-(void)requestURL:(NSURLRequest *)request withResult:(ResultBlock)resultHandler{
//URLSession
NSURLSession *session = [NSURLSession sharedSession];
NSURLSessionDataTask *task = [session dataTaskWithRequest:request completionHandler:^(NSData * data, NSURLResponse * response, NSError * error) {
if(!error){
NSError *jsonError = nil;
id result = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&jsonError];
if([result isKindOfClass:[NSArray class]]){
//Success
resultHandler(result,nil);
}
else if([result isKindOfClass:[NSDictionary class]]){
if([[result objectForKey:#"error"] integerValue]){
//Failure.
NSMutableDictionary *errorDetail = [NSMutableDictionary dictionary];
[errorDetail setValue:[result objectForKey:#"message"] forKey:NSLocalizedDescriptionKey];
NSError *error = [NSError errorWithDomain:#"Error" code:100 userInfo:errorDetail];
resultHandler(nil, errorDetail);
}
}
}
}];
[task resume];
}
//Call your requestURL method:
[self requestURL:request withResult:^(id result, NSError *error){
if(!error){
//Success, Read & update your list
}
else{
//Error
// NSLog(error.localizedDescription());
}
}];