I am using AFNetworking to get data from a server:
-(NSArray)some function {
AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
success: ^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
NSArray *jsonArray =[JSON valueForKey:@"posts"];
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {}
}
So what I am trying to do here is to return the jsonArray to the function. Obviously return is not working.
You can't use the completion Block to create a return value for your method. The AFJSONRequestOperation
does its work asynchronously. someFunction
is going to return while the operation is still working. The success and failure Blocks are how you get resulting values where they need to go.
One option here is to pass in the caller as an argument to your wrapper method so that the completion Block can hand the array off.
- (void)goFetch:(id)caller
{
AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
success: ^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
[caller takeThisArrayAndShoveIt:[JSON valueForKey:@"posts"]];
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {}
}
You could also make your caller create and pass a Block to be run on success. Then goFetch:
no longer needs to know what properties exist on the caller.
- (void)goFetch:(void(^)(NSArray *))completion
{
AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
success: ^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
if( completion ) completion([JSON valueForKey:@"posts"]);
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {}
}
As others have said, you can't do that when dealing with async call. Instead of returning the expected Array, you could pass a completion block as a parameter
typedef void (^Completion)(NSArray* array, NSError *error);
-(void)someFunctionWithBlock:(Completion)block {
AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request
success: ^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
NSArray *jsonArray =[JSON valueForKey:@"posts"];
if (block) block(jsonArray, nil);
}
failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {
if (block) block(nil, error);
}
}
Then where you call that someFunction. This code will also do proper error handling for you.
[yourClassInstance someFunctionWithBlock:^(NSArray* array, NSError *error) {
if (error) {
NSLog(%@"Oops error: %@",error.localizedDescription);
} else {
//do what you want with the returned array here.
}
}];
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With