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我正在使用 AFNetworking，并且我读过不鼓励同步响应。但是我需要检查用户是否已经存在于在线数据库中，然后该用户才能进入应用程序的下一阶段。是的，一个典型的注册过程。

我的代码现在返回 NO，因为它是异步的。我需要找到一种方法来检查成功调用并返回YES或NO取决于此回调。

谁能指出我如何编写等待成功调用的应用程序的正确方向，以便我知道尚未设置用户？

-(BOOL)doesTheUserExistAlreadyOnServer:(NSString *)parsedEmail
{
    BOOL *methodResponse = NO;

    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"http://www.myurl.co.uk/"]];
    NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST"
                                                            path:@"http://www.myurl.co.uk/igym.php"
                                                      parameters:@{@"myvar2":@"piggy"}];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    [httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        // Print the response body in text

      //  NSLog(@"Response: %@", [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding]);
        if ([[[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding] isEqualToString:@"piggy"]) {
            __block methodResponse = YES;
            NSLog(@"%@",[[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding]);
        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];
    [operation start];

    return (BOOL)methodResponse;

}

编辑：

我使用以下逻辑解决了这个问题。

用户点击注册按钮。main 方法执行所有初步的非 Web 检查，然后调用[self doesTheUserExistAlreadyOnServer:_email.text];

该方法代码现在是

-(void)doesTheUserExistAlreadyOnServer:(NSString *)parsedEmail
{ 
    if(![_spinner isAnimating])
    {
        [_spinner startAnimating];
    }

    __block RegistrationViewController* me = self;
    AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:[NSURL URLWithString:@"http://www.myurl.co.uk/"]];
    NSMutableURLRequest *request = [httpClient requestWithMethod:@"POST"
                                                            path:@"http://www.myurl.co.uk/igym.php"
                                                      parameters:@{@"myvar2":@"piggy"}];
    AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc] initWithRequest:request];
    [httpClient registerHTTPOperationClass:[AFHTTPRequestOperation class]];
    [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
        // Print the response body in text

        if ([[[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding] isEqualToString:@"piggy"]) {

            NSLog(@"%@",[[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding]);
            [me registrationPartTwo:YES];
        } else
        {
            [me registrationPartTwo:NO];
        }
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];

    [operation start];

}

然后，一旦该块/回调成功，它就会调用

-(void)registrationPartTwo:(BOOL)doesItExistOnServer
{
    [_spinner stopAnimating];
    NSString *emailAlreadyInUseMessage = [NSString stringWithFormat:@"This email is already in use"];
    if (doesItExistOnServer)
    {
        self.screenMsg.text = emailAlreadyInUseMessage;
//here more code to send the user the the next step
    }
}

基本上我使用依赖于回调的 2method 注册过程解决了这个问题，不知道那是最好还是最有效的方法。但这就是我可以自己解决的方法。

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1 回答 1

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使用委托回调来通知操作何时完成。如果需要，在开始操作之前，放置一个UIActivityIndicatorView（微调器）以防止用户与应用程序交互。

于 2013-04-15T22:25:58.247 回答