How to solve warning message: Sending 'viewController const __strong to parameter of incompatible type 'id<nsurlsessiondelegate>

Question

The following code gave a warning of :

Sending 'viewController const __strong to parameter of incompatible type 'id

Here is my code:

- (void)postRequestWithParam: (NSDictionary *)param onCompletion: (CompletionHandler)completionHandler

{
NSError *error;


NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

configuration.timeoutIntervalForRequest = 30.0;

NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil];



NSURL *url = [NSURL URLWithString: @"http://test.demo.net/demoapp/index.php"];

NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                   timeoutInterval:60.0];

[request setHTTPMethod:@"POST"];

if(param == nil)

    param = [NSDictionary dictionary];


NSData *postData = [NSJSONSerialization dataWithJSONObject:param options:0 error:&error];

NSString *postLength = [NSString stringWithFormat:@"%lu", (unsigned long)[postData length]];


[request setValue:postLength forHTTPHeaderField:@"Content-Length"];

[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];


[request setHTTPBody:postData];


NSURLSessionDataTask *postDataTask = [session dataTaskWithRequest:request
                                                completionHandler:^(NSData *data, NSURLResponse *response, NSError *error)
                                      {
                                          if (!error)
                                          {
                                              completionHandler(YES, [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error], nil);

                                              NSString *responseStr = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
                                              NSLog(@"res...%@",responseStr);

                                              NSLog(@"RESPONSE:  %@", [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error]);
                                          }

                                          else
                                          {
                                              completionHandler(NO, nil, error);
                                          }
                                      }];

[postDataTask resume];
}

Answer 1

Confirm <NSURLSessionDelegate> in your header file and it will solve the issue i think,

  @interface ViewController : UIViewController <NSURLSessionDataDelegate>

It is because you are setting delegate to self in NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil]; So it's requires to confirm NSURLSessionDataDelegate protocol.