iphone 上不显示弹出框

popover doesn't display on iphone

我遵循了这个 但没有在 iphone 上生成弹出窗口。 这是 viewcontroller

的代码
class ViewController:UIViewController,UIPopoverPresentationControllerDelegate{

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if segue.identifier == "second"{

            let secondVC = segue.destination
            let controller : UIPopoverPresentationController = secondVC.popoverPresentationController!
            controller.delegate = self
        }
    }

    /* Popover delegate method */
    func adaptivePresentationStyleForPresentationController(controller: UIPresentationController) -> UIModalPresentationStyle {
        return UIModalPresentationStyle.none
    }
}

我无法在 iphone 中使用 present 作为弹出框来显示新的 viewcontroller。 (ios 10/xcode8)

After clicking on button secondViewController should popover on that button.

使用此委托方法后,它会在 iphone 上生成弹出窗口。

func adaptivePresentationStyle(for controller: UIPresentationController, traitCollection: UITraitCollection) -> UIModalPresentationStyle {

    return UIModalPresentationStyle.none
}