如何从NSURLSessionDataTask获取NSDictionary

问题描述

-(NSDictionary *)fetchFromUrl:(NSString *)url{
    NSURLRequest *request = [NSURLRequest  requestWithURL:[NSURL URLWithString:url]];
    NSURLSession *session = [NSURLSession sharedSession];
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request
                                        completionHandler:
                              ^(NSData *data, NSURLResponse *response, NSError *error) {
                                  dataFetched = [NSJSONSerialization JSONObjectWithData:data
                                                                                           options:0
                                                                                             error:NULL];

                              }];
    [task resume];
    NSLog(@"dataFetched, %@", dataFetched);

    return dataFetched;
}

因此，我尝试将dataFetched用作全局变量，以便可以在.m文件中访问它，并使其他.m文件可以访问它，但是当我尝试从其他.m文件中NSLog dataFetched时，它将输出(空).无论如何，我可以在需要数据的其他.m文件中使数据可访问吗?

So I have tried putting the dataFetched as a global variable so I could access it around my .m file and make it accessible to other .m file but when I tried to NSLog the dataFetched from other .m file it outputs (null). Is there anyway I could make the data accessible throughout my other .m files that needed the data?

推荐答案

您需要在您的方法中使用block，而不是返回NSDictionary，因此请像这样更改代码.

You need to use block with your method, instead of returning NSDictionary, So change your code like this.

首先像这样更改您的方法

First Change your method like this

-(void)fetchFromUrl:(NSString *)url withDictionary:(void (^)(NSDictionary* data))dictionary{
    NSURLRequest *request = [NSURLRequest  requestWithURL:[NSURL URLWithString:url]];
    NSURLSession *session = [NSURLSession sharedSession];
    NSURLSessionDataTask *task = [session dataTaskWithRequest:request
                                            completionHandler:
                                  ^(NSData *data, NSURLResponse *response, NSError *error) {
                                      NSDictionary *dicData = [NSJSONSerialization JSONObjectWithData:data
                                                                                    options:0
                                                                                      error:NULL];
                                      dictionary(dicData);
                                  }];
    [task resume];
}

现在像这样调用您的方法

Now call your method like this

[self fetchFromUrl:urlStr withDictionary:^(NSDictionary *data) {
    self.dataFetched = data;
    NSLog(@"data %@",data);
}];

这篇关于如何从NSURLSessionDataTask获取NSDictionary的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！