从SKScene中删除MFMailComposeViewController

我打开了 MFMailComposeViewController 从…起 SKScene 以这种方式:

-(void)sendmail {

if ([MFMailComposeViewController canSendMail]) {

    MFMailComposeViewController *mailer = [[MFMailComposeViewController alloc] init];
    mailer.delegate = self;
    NSArray *recipients = [NSArray arrayWithObjects:@"nothing@gmail.com", nil];
    [mailer setToRecipients:recipients];

    UIViewController *vc = self.view.window.rootViewController;
    [vc presentViewController:mailer animated:YES completion:nil];
 }
}

这是可行的,但当我想回到 SK场景 委托方法未被调用,无法返回。

这是SKScene的.h:

 @interface SettingScene : SKScene <UINavigationControllerDelegate, MFMailComposeViewControllerDelegate>

怎么了?

谢谢