CODEWITHSUNDEEP
objective-cblock
doxsi
doxsi

Reputation: 1024

Objective-c : How method using block can returns object

I have a method that should return a dict:

-(NSDictionary *) searcherMethod: (NSString *) text {

         [ReadService readFromApi:APIURL

                 whenFinish:^(id responseObject) {

                //HERE I have A response from API
                NSDictionary *response = (NSDictionary*)responseObject;

               //HOW  searcherMethod can return the response dict?
              return response;
          }];        
}

How make that searcherMethod can return the response dict?

Upvotes: 2

Views: 241

Answers (1)

MobileMatrix
MobileMatrix

Reputation: 162

The response from the API call return asynchronously, so you have to write block for return the result while you have got the response from API.

The below code help you to achieve your requirements.
This code will return response asynchronously

-(void) searcherMethod: (NSString *) text  responseCompletion:(void (^_Nullable)(NSDictionary *))responseCompletion{

    [ReadService readFromApi:APIURL

                  whenFinish:^(id responseObject) {

                      //HERE I have A response from API
                      NSDictionary *response = (NSDictionary*)responseObject;

                      //HOW  searcherMethod can return the response dict?
                      if (responseCompletion) {
                          responseCompletion(response);
                      }
                  }];
}


This code will return response synchronously

-(NSDictionary *) searcherMethod: (NSString *) text  {

    NSDictionary *response = nil;
    // create the semaphore for synchronously call
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

    [ReadService readFromApi:APIURL

                  whenFinish:^(id responseObject) {

                      //HERE I have A response from API
                      response = (NSDictionary*)responseObject;

                      // fire signal for semaphore so your code will execute further
                      dispatch_semaphore_signal(semaphore);
                  }];
    dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
    return response;
}

Semaphore is blocking the execution until the signal is not received, this will return your method after receiving the response.
you can use below code for the method call.

[self searcherMethod:@"responseText" responseCompletion:^(NSDictionary *responseDict) {
        //result
        NSLog(@"Response : %@",responseDict);
    }];

Now you can call your method synchronously

NSDictinary *response = [self searcherMethod:text]

Hope this will help you.

Upvotes: 2

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