iOS method reuse (pass parameters)

Question

I have an url request method, because each page will be used, I want to make it public. （Poor standard of English, forgive me） here is my class method:

- (void)httpRequest :(NSString *)url :(NSMutableArray *)array;

{

    NSURL *myUrl = [NSURL URLWithString:url];

    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:myUrl cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10];

    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];

    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject)

     {

         NSLog(@"请求完成");

         NSArray *arr;

         arr = [NSJSerialization JSONObjectWithData:operation.responseData options:NSJSONReadingAllowFragments error:NULL];

         [array addObjectsFromArray:arr];

            ？？？？？？？

     }failure:^(AFHTTPRequestOperation *operation, NSError *error){

         NSLog(@"请求失败: %@", error);
            ？？？？？？
     }];
    [operation start];
}

I know how to pass simple parameters,like array and url.But when I use this method,code in the question mark will be different everytime.What can I do to make it can be passed,like parameters.

Like: [myApple httpRequest :myurl :myarray : (susucess .....) : (failure......)]; the question mark can be filled in: mytableView reloadData or nslog...
I'm not sure if i explained my question clearly,i don't know if block can solve this,thanks,waiting for your help.

Answer 1

Firstly, note that all method parameters in Objective-C should be named. So instead of - (void)httpRequest :(NSString *)url :(NSMutableArray *)array;, you should have something like:

- (void)performHttpRequestWithURL:(NSString *)url resultsArray:(NSMutableArray *)array; 

To answer your question, you could pass your own completion block into your method. You can then call this block once AFNetworking has completed its HTTP request.

- (void)performHTTPRequestWithURL:(NSString *)urlString completion:(void (^)(NSArray *results, NSError *error))completion
{
    NSURL *url = [NSURL URLWithString:urlString];

    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url 
                                                  cachePolicy:NSURLRequestUseProtocolCachePolicy 
                                              timeoutInterval:10];

    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];

    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject)
    {
        NSLog(@"请求完成");

        NSArray *results = [NSJSerialization JSONObjectWithData:operation.responseData options:NSJSONReadingAllowFragments error:nil];

        if (completion)
            completion(results, nil);
    }
    failure:^(AFHTTPRequestOperation *operation, NSError *error)
    {
        NSLog(@"请求失败: %@", error);

        if (completion)
            completion(nil, error);
    }];

    [operation start];
}

You could then call your method and pass in a block:

[self performHTTPRequestWithURL:@"http://www.example.com" completion:^(NSArray *results, NSError *error) {
    if (error) 
    {
          // handle error
    }
    else
    {
        // reload tableview or similar
    }
 }];

Take a look at Apple's Blocks Programming Guide for more information on blocks.