iOS - NSURLConnection异步请求一次，然后失败（挂起）第二次尝试

问题描述：

我有一个登录视图，用户将用于登录到我的应用程序。我使用NSURLConnection Asynchrounous请求块连接到我的Web服务并来回传递数据。iOS - NSURLConnection异步请求一次，然后失败（挂起）第二次尝试

我有一个奇怪的问题，如果用户第一次登录，它工作正常。但是，如果他们注销，然后尝试再次登录请求发送，但从来没有响应（我设置所有场景的alertviews;即超时，数据=无，错误！=零等）。它只是与我显示的加载屏幕坐在那里，并从不做任何事情。

我是否错过了什么？

[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) 
    { 
     if ([data length] > 0 && error == nil){ 
      if(data != nil) { 
        //Handle Data Here 
        .............  
      } else { 
       [loadingView removeFromSuperview]; 
       loadingView = nil; 
       BlockAlertView *alert = [BlockAlertView alertWithTitle:@"Network Error" message:@"Network connection was successful, but there was a problem with data transfer.\nPlease try again."]; 
       [alert setCancelButtonWithTitle:@"OK" block:nil]; 
       [alert show];    } 
     } 
     else if ([data length] == 0 && error == nil){ 
      [loadingView removeFromSuperview]; 
      loadingView = nil; 
      BlockAlertView *alert = [BlockAlertView alertWithTitle:@"Network Error" message:@"Network connection was successful, but there was a problem with data transfer.\nPlease try again."]; 
      [alert setCancelButtonWithTitle:@"OK" block:nil]; 
      [alert show]; 
     } 
     else if (error != nil && error.code == NSURLErrorTimedOut){ 
      [loadingView removeFromSuperview]; 
      loadingView = nil; 
      BlockAlertView *alert = [BlockAlertView alertWithTitle:@"Network Error" message:@"The network request timed out.\nPlease check your internet connection and try again."]; 
      [alert setCancelButtonWithTitle:@"OK" block:nil]; 
      [alert show]; 
     } 
     else if (error != nil){ 
      [loadingView removeFromSuperview]; 
      loadingView = nil; 
      BlockAlertView *alert = [BlockAlertView alertWithTitle:@"Network Error" message:@"There was a problem connecting to the network.\nPlease check your internet connection and try again."]; 
      [alert setCancelButtonWithTitle:@"OK" block:nil]; 
      [alert show]; 
     } 
    }];

答

好的解决了这个问题。与我正在使用的委托指派有关的问题是，我通知我的观点，我完成了处理/保存响应数据并执行赛格。由于代理正在viewDidLoad中设置，当下一个视图出现并接管委托时，登录视图失去了委托控制。只需将委托任务移至viewWillAppear（或viewDidAppear）。

iOS - NSURLConnection异步请求一次，然后失败（挂起）第二次尝试

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