Question

当我尝试从UICollectionViewController调用Custom UIPresentationController时，我的应用程序崩溃了

@IBAction func showSettingsMenu(sender: UIBarButtonItem) {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    if let mvc = storyboard.instantiateViewControllerWithIdentifier(Constants.SettingsViewControllerId) as? SettingsViewController {        
    mvc.modalPresentationStyle = .Custom
    mvc.transitioningDelegate = self
    presentViewController(mvc, animated: true, completion: nil)
}

}

这是我的自定义演示文稿视图控制器：

class SpecialSizePresentationController: UIPresentationController {
    override func frameOfPresentedViewInContainerView() -> CGRect {
        guard let height = containerView?.bounds.height else {
            return CGRectZero
        }

        guard let width = containerView?.bounds.width else {
            return CGRectZero
        }
        let y = height * 0.6
        let frameHeight = height * 0.4

        return CGRectMake(8, y - 8 , width - 8 - 8 , frameHeight)
    }
}

这是我的UICollectionViewController中的UIViewControllerTransitioningDelegate协议实现：

func presentationControllerForPresentedViewController(presented:   UIViewController, presentingViewController presenting: UIViewController, sourceViewController source: UIViewController) -> UIPresentationController? {        
     return SpecialSizePresentationController(presentedViewController: presented, presentingViewController: presenting)
}

并且app在错误的返回位置崩溃（由于呈现为零）：

fatal error: unexpectedly found nil while unwrapping an Optional value

是否可以从UICollectionViewController呈现自定义Presentation Controller？

如何实施？

Answer 1

我使用source presenting的{{1}}问题解决了这个问题，错误消失了

应用程序因UICollectionViewController崩溃而无法呈现ViewController

1 个答案: