呈现MFMailComposeViewController,但它在可见后立即消失

Question

我的应用程序中的第一个ViewController是UIImagePickerController的子类,然后通过didFinishPickingMediaWithInfo回调,我执行以下操作:

EditViewController *editViewController = [[EditViewController alloc] initWithNibName:@"EditViewController" bundle:nil];
[self pushViewController:editViewController animated:YES];

这个ViewController正确显示...然后,通过IBAction,我执行以下操作:

PreviewViewController *previewViewController = [[PreviewViewController alloc] initWithNibName:@"PreviewViewController" bundle:nil];
previewViewController.tempImage = img;
[self.navigationController pushViewController:previewViewController animated:YES];

此视图也正确显示.在这个VC我试图使用MFMailComposeViewController发送电子邮件.当我试图推动它时,我得到Pushing导航控制器不支持:

MFMailComposeViewController *mailViewController = [[MFMailComposeViewController alloc] init];
mailViewController.mailComposeDelegate = self;
[mailViewController setSubject:@"Subject Goes Here."];
[mailViewController setMessageBody:@"Your message goes here." isHTML:NO];
[self.navigationController pushViewController:mailViewController animated:YES];

但是当我提出它时:

[self presentModalViewController:mailViewController animated:YES];

mailViewController只出现一秒然后消失,我看到一个黑色背景(但不是之前的VC视图),顶部有一个空的导航栏.该应用程序此时仍在运行.

我究竟做错了什么？

Answer 1

如果您仍想推送mailViewController,则可以执行此操作(仅限iOS 7):

UIViewController *theMailViewController = [[mailViewController viewControllers] lastObject];
[self.navigationController pushViewController:theMailViewController animated:YES];

这样,MailViewController的rootViewController将被推送到您的实际navigationController中.

我希望这可以帮助你.