UIViewControllerHierarchyConsistency-一个视图一次最多只能有一个视图控制器

Question

我在更新我的一个旧应用程序时遇到问题，这是因为我更新到Xcode 4.5并尝试iOS6后才出现以下错误；

*** Terminating app due to uncaught exception 'UIViewControllerHierarchyInconsistency', reason: 'A view can only be associated with at most one view controller at a time! View <MainView: 0x1e818620; frame = (0 0; 320 476); autoresize = RM+BM; layer = <CALayer: 0x1e818750>> is associated with <MainViewController: 0x1e811850>. Clear this association before associating this view with <UIViewController: 0x21149860>.'

*第一次抛出调用堆栈：(0x377d82a3 0x35ae897f 0x377d81c5 0x38b0dd7b 0x38b0dc6b 0x1dc25 0x38b940 ad 0x38b9405f 0x38b9303d 0x38b938f3 0x38bc5f9 0x38a9809 0x38aa9123 0x37c5c5a3 0x37c51d3 0x37ad173 0x37ad117 0x37abf99 0x37aebd 0x377ed49 0x37cb2eb 0x38fd301 0x1bf03 0x1bea8)libc++abi.dylib：调用terminate引发异常[切换到进程9219线程0x2403]

我认为正是这里造成了这个问题；

mailComposer = [[UIViewController alloc] init];
[mailComposer setView:self];
[mailComposer setModalTransitionStyle: UIModalTransitionStyleCoverVertical];


MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];   picker.mailComposeDelegate = self;

当我点击该按钮时，我会进入MFMail编辑器，也就是应用程序崩溃的时候。

有什么想法吗？

提前感谢

编辑-如果我删除前3行，应用程序不会崩溃，但邮件视图不会加载。。。以下是整个代码；

// The actual mail window call

mailComposer = [[UIViewController alloc] init];
[mailComposer setView:self];
[mailComposer setModalTransitionStyle: UIModalTransitionStyleCoverVertical];


MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];   picker.mailComposeDelegate = self;
[picker setSubject:@"Hello How are you"];
// Fill out the email body text
NSString *pageLink = @"http://www.apple.com"; 
NSString *iTunesLink = @"http://itunes.apple.com/gb/artist/randomer";
NSString *content = @"blah blah"; 

NSString *emailFileName = [NSString stringWithFormat:@"email_.html"];

NSString *emailFilePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent: emailFileName];
NSString *body = [NSString stringWithContentsOfFile:emailFilePath encoding:NSUTF8StringEncoding error:nil];

body = [body stringByReplacingOccurrencesOfString:@"//TEXT_PLACEHOLDER//" withString:@"replace here"];
body = [body stringByReplacingOccurrencesOfString:@"//FRIENDNAME_PLACEHOLDER//" withString:pageLink];
body = [body stringByReplacingOccurrencesOfString:@"//ITUNES_PLACEHOLDER//" withString:  iTunesLink];
body = [body stringByReplacingOccurrencesOfString:@"//PASSKEY_PLACEHOLDER//" withString:  yourPassword];
body = [body stringByReplacingOccurrencesOfString:@"//PHONETIC_PLACEHOLDER//" withString:  yourPhoneticPassword];


[picker setMessageBody:body isHTML:YES];    
picker.navigationBar.barStyle = UIBarStyleBlack;    
[mailComposer presentModalViewController:picker animated:YES];
[picker release];

}

//HANDLE THE MAIL EVENTS
////////////////////////

• (void)mailComposeController:(MFMailComposeViewController*)控制器didFinishWithResult:(MFMailComposeResult)结果错误：(NSError*)错误｛//通知用户与接口相关的错误开关(结果){case MFMailComposeResultCancelled：打破case MFMailComposeResultSaved:打破case MFMailComposeResultSent:打破case MFMailComposeResultFailed:打破

  default:
  {
  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Email" message:@"Sending Failed - Unknown Error :-("
  delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
  [alert show];
  [alert release];
  }
  break;
  

  }[mailComposer解雇ModalViewControllerAnimated:YES]；//[mailComposer.view.superview removeFromSuperview]；}

Answer 1

让邮件组成视图控制器显示的主要内容是使用当前活动的UIViewController来显示它。你没有分享足够的代码让我清楚，但如果self在这种情况下是UIViewController，你需要做：

[self presentViewController:picker animated: YES completion:nil];

如果self不是UIViewController，请将上面代码中的self替换为引用当前UIViewController的变量。