Objective c 无法在iOS8上的UIAlertController内显示UIPickerView

之前我使用的是UIactionSheet，但由于它已被弃用，所以我尝试使用UIAlertController来显示UIPicker。 下面是我用来将选择器添加到UIAlertController的代码

        UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"some_title"
                                                                             message:nil
                                                                      preferredStyle:UIAlertControllerStyleActionSheet];
    [alertController setModalPresentationStyle:UIModalPresentationPopover];
    [alertController.view addSubview:_formatPickerView];
    UIPopoverPresentationController *popPresenter = [alertController
                                                     popoverPresentationController];
    // cell is a cell from a tableview
    popPresenter.sourceView = cell;
    popPresenter.sourceRect = cellRect;
    [self presentViewController:alertController animated:NO completion:nil];

这将调出AlertController，但不带拾取器

一个有趣的观察结果是，如果我在中更改

preferredStyle

[UIAlertController alertControllerWithTitle:@“一些标题”
消息：无首选样式：UIAlertControllerStyleActionSheet]

从
UIAlertControllerStyleActionSheet
到
UIAlertControllerStyleAlert
然后我开始获取选择器，但我失去了对UIAlertController位置的控制

        UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"some_title"
                                                                             message:nil
                                                                      preferredStyle:UIAlertControllerStyleActionSheet];
    [alertController setModalPresentationStyle:UIModalPresentationPopover];
    [alertController.view addSubview:_formatPickerView];
    UIPopoverPresentationController *popPresenter = [alertController
                                                     popoverPresentationController];
    // cell is a cell from a tableview
    popPresenter.sourceView = cell;
    popPresenter.sourceRect = cellRect;
    [self presentViewController:alertController animated:NO completion:nil];

我想要控制UIAlertController的位置，因此我使用的是
UIAlertControllerStyleActionSheet

以前有人见过这个问题吗？感谢您的帮助。谢谢
 我通过在
UIActionSheet
中显示
UIPickerView
解决了这个问题

UIActionSheet* actionSheet = [[UIActionSheet alloc] initWithTitle:@"\n\n\n\n\n\n\n\n\n\n"
                                                             delegate:nil
                                                    cancelButtonTitle:nil
                                               destructiveButtonTitle:nil
                                                    otherButtonTitles:nil];
    actionSheet.delegate = self;
    [actionSheet addSubview:_formatPickerView];
    UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
    CGRect cellRect = cell.bounds;
    cellRect.size.width = cell.frame.size.width * 2;
    cellRect.origin.x = -(cell.frame.size.width/2);

    [actionSheet showFromRect:cellRect inView:cell animated:YES];