ipad – 在iOS8中更改Action Sheet popover箭头

我正在使用UIAlertController。但是在iPad与iOS 8，actionSheet显示与popover箭头。任何想法隐藏的箭头？

这是我的代码：

UIAlertController *alertController = [UIAlertController alertControllerWithtitle:@"this is alert controller" message:@"yeah" preferredStyle:UIAlertControllerStyleActionSheet];

            UIAlertAction *cancelAction = [UIAlertAction
                                           actionWithtitle:NSLocalizedString(@"Cancel",@"Cancel action")
                                           style:UIAlertActionStyleCancel
                                           handler:^(UIAlertAction *action)
                                           {
                                               NSLog(@"Cancel action");
                                           }];

            UIAlertAction *okAction = [UIAlertAction
                                       actionWithtitle:NSLocalizedString(@"OK",@"OK action")
                                       style:UIAlertActionStyleDefault
                                       handler:^(UIAlertAction *action)
                                       {
                                           NSLog(@"OK action");
                                       }];

            UIAlertAction *deleteAction = [UIAlertAction
                                           actionWithtitle:NSLocalizedString(@"delete",@"delete action")
                                           style:UIAlertActionStyleDestructive
                                           handler:^(UIAlertAction *action) {
                                               NSLog(@"delete action");
                                           }];

            [alertController addAction:cancelAction];
            [alertController addAction:okAction];
            [alertController addAction:deleteAction];

            UIPopoverPresentationController *popover = alertController.popoverPresentationController;
            if (popover) {
                popover.sourceView = self.view;
                popover.sourceRect = self.view.bounds;
                popover.permittedArrowDirections = UIPopoverArrowDirectionUnkNown;
            }
            [self presentViewController:alertController animated:YES completion:nil];

[yourAlertController.popoverPresentationController setPermittedArrowDirections:0];

UIAlertController *alertController = [UIAlertController alertControllerWithtitle:@"Test Action Sheet" message:@"message" preferredStyle:UIAlertControllerStyleActionSheet];

    UIAlertAction *cancelAction = [UIAlertAction
                                   actionWithtitle:@"Cancel"
                                   style:UIAlertActionStyleDestructive
                                   handler:^(UIAlertAction *action)
                                   {
                                       NSLog(@"Cancel action");
                                   }];

    UIAlertAction *okAction = [UIAlertAction
                               actionWithtitle:@"Ok"
                               style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction *action)
                               {
                                   NSLog(@"OK action");
                               }];
    UIAlertAction *otherAction = [UIAlertAction
                               actionWithtitle:@"Other"
                               style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction *action)
                               {
                                   NSLog(@"Otheraction");
                               }];

    [alertController addAction:okAction];
    [alertController addAction:otherAction];
    [alertController addAction:cancelAction];


    // Remove arrow from action sheet.
    [alertController.popoverPresentationController setPermittedArrowDirections:0];

    //For set action sheet to middle of view.
    alertController.popoverPresentationController.sourceView = self.view;
    alertController.popoverPresentationController.sourceRect = self.view.bounds;

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