调整PopOver视图控制器的大小

Question

我有一个视图控制器，我想将其作为弹出窗口呈现。我该如何改变它的大小？

    let carsViewController = CarsViewController()
    carsViewController.modalPresentationStyle = .Popover

    if let popoverPresentationController = a carsViewController.popoverPresentationController {
        popoverPresentationController.permittedArrowDirections = .Up
        popoverPresentationController.sourceView = carsButton
        presentViewController(alertsViewController, animated: true, completion: nil)
    }

Answer 1

花了我一些时间，但我终于找到了答案。它就像初始化视图控制器后添加以下行一样简单。

carsViewController.preferredContentSize = CGSize(width: 220,height:90)