iOS11presentViewController落后于呈现控制器

我有一个奇怪的问题,我只是做一个简单的呈现模态视图控制器.MFMailComposeViewController确切地说.但是,它出现在呈现控制器后面,因此您无法发送任何电子邮件或类型.您可以UINavigationBar在邮件编辑器上看到"取消"按钮,但会弹出UIAlertController显示控制器的后面.这是怎么发生的？这是iOS 11问题吗？对于UIAlertControllers 我也有类似的行为.

此外,如果我按下发送并按下我的按钮以弹出另一个Composer,它将正常工作.这只是第一个.

请参阅我从Xcode获得的附图.

MFMailComposeViewController *mailer = [[MFMailComposeViewController alloc] init];
mailer.mailComposeDelegate = self;
mailer.modalPresentatiOnStyle= UIModalPresentationFormSheet;
[mailer setSubject:@"subject Feedback"];
[mailer setToRecipients:@[@"email address"]];
[mailer setMessageBody:@"" isHTML:NO];
[self presentViewController:mailer animated:YES completion:nil];

编辑:添加控制器以获取更多信息.

#import "AboutViewController.h"
#import 


@interface AboutViewController () 
@property (nonatomic, strong) IBOutlet UIView *contentView;
@end

@implementation AboutViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"About this app";
    _contentView.layer.cornerRadius = 10.;
    _contentView.layer.shadowColor = [UIColor blackColor].CGColor;
    _contentView.layer.shadowRadius = 3.;
    _contentView.layer.shadowOpacity = 0.4;
    _contentView.layer.shadowOffset = CGSizeMake(3., 3.);
    // Do any additional setup after loading the view from its nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)sendFeedbackEmail:(id)sender {
    if ([MFMailComposeViewController canSendMail]){
        dispatch_async(dispatch_get_main_queue(), ^{
            MFMailComposeViewController *mailer = [[MFMailComposeViewController alloc] init];
            mailer.mailComposeDelegate = self;
            mailer.modalPresentatiOnStyle= UIModalPresentationFormSheet;
            [mailer setSubject:@"Feedback"];
            [mailer setToRecipients:@[@"email@email.com"]];
            [mailer setMessageBody:@"" isHTML:NO];
            [self presentViewController:mailer animated:YES completion:nil];

        });
    } else {
        NSLog(@"Nope");
    }
}

- (void)mailComposeController:(MFMailComposeViewController*)controller didFinishWithResult:(MFMailComposeResult)result error:(NSError*)error
{
    [controller dismissViewControllerAnimated:YES completion:nil];
}

编辑2:

我相信我找到了答案.我希望这可以帮助遇到同样问题的人.感谢所有的回复,它帮助我找到了答案.谢谢@Mert Buran代表的想法.这向我展示了它第一次有一个不同的过渡代表,第二次有我想要的那个.

问题是navigationController在解除我在顶部的控制器(菜单控制器)之前推动了新的控制器.一个简单的修复,但因为它在开始时并不明显,没有错误日志,所以很难确定.