Question

我有一个单例类，我已经实现了一个通过URL解析json数据的方法。代码如下

-(id)parseJsonDataWIthURL:(NSString *)url :(NSString*)datumm
{

    NSMutableDictionary *arrrrr=[[NSMutableDictionary alloc]init];



            NSMutableURLRequest *reqqq=[[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]];

            NSData *dataaa=[datumm dataUsingEncoding:NSUTF8StringEncoding];
            [reqqq setHTTPMethod:@"POST"];
            [reqqq setHTTPBody:dataaa];

            NSURLSessionConfiguration *configg=[NSURLSessionConfiguration defaultSessionConfiguration];
            NSURLSession*sessionn=[NSURLSession sessionWithConfiguration:configg delegate:nil delegateQueue:[NSOperationQueue mainQueue]];

            NSURLSessionDataTask *taskk=[sessionn dataTaskWithRequest:reqqq completionHandler:^(NSData *data,NSURLResponse *responce,NSError *error){
                if(error)
                {
                    NSLog(@"%@", [error localizedDescription]);
                }else{
                    NSMutableDictionary *d = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments|NSJSONReadingMutableContainers error:&error];
                    NSLog(@"data %@",d);
                    [arrrrr setDictionary:d];
                }
            }];
            [taskk resume];


    return arrrrr;
}

该方法不返回任何值，这是因为块在该方法中执行时需要时间才能返回结果。那么有没有办法等到块完成并返回值。

Answer 1

ragul ml，

我建议的最简单的解决方案是使用块：）

以下是如何实现它:)将-(id)parseJsonDataWIthURL:(NSString *)url :(NSString*)datumm修改为，

-(void)parseJsonDataWIthURL:(NSString *)url :(NSString*)datumm withCompletionBlock:(void(^)(NSMutableArray *))completionBlock 
{

    NSMutableDictionary *arrrrr=[[NSMutableDictionary alloc]init];



            NSMutableURLRequest *reqqq=[[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]];

            NSData *dataaa=[datumm dataUsingEncoding:NSUTF8StringEncoding];
            [reqqq setHTTPMethod:@"POST"];
            [reqqq setHTTPBody:dataaa];

            NSURLSessionConfiguration *configg=[NSURLSessionConfiguration defaultSessionConfiguration];
            NSURLSession*sessionn=[NSURLSession sessionWithConfiguration:configg delegate:nil delegateQueue:[NSOperationQueue mainQueue]];

            NSURLSessionDataTask *taskk=[sessionn dataTaskWithRequest:reqqq completionHandler:^(NSData *data,NSURLResponse *responce,NSError *error){
                if(error)
                {
                    NSLog(@"%@", [error localizedDescription]);
                    completionBlock(nil)
                }else{
                    NSMutableDictionary *d = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments|NSJSONReadingMutableContainers error:&error];
                    NSLog(@"data %@",d);
                    [arrrrr setDictionary:d];
                    if (completionBlock) {
                          completionBlock(arrrrr);
                    }
                }
            }];
            [taskk resume];
}

最后修改你的电话，

[[YourSingletonClass sharedInstance] parseJsonDataWIthURL:your_url :datumm withCompletionBlock:^(NSMutableArray *array) {
        if (array){
            //web service is successful
        }
    }];

如何使用单例类

1 个答案: