iOS 13 modalPresentationStyle = UIModalPresentationFullScreen 不适用于 MFMessageComposeViewController答案

【问题标题】：iOS 13 modalPresentationStyle = UIModalPresentationFullScreen not working for MFMessageComposeViewControlleriOS 13 modalPresentationStyle = UIModalPresentationFullScreen 不适用于 MFMessageComposeViewController
【发布时间】：2019-11-25 11:51:37
【问题描述】：

从 iOS 13+ 的模态显示样式中我们都知道，普通 UIViewController 将默认为 .pageSheet。如果您想更改它，您可以在展示时将其更改为您想要的样式。我在我的应用程序中使用 MFMailComposeViewController 和 MFMessageComposeViewController 来共享内容。在 MFMailComposeViewController 的情况下，当我选择 modalPresentationStyle = .fullScreen 时，它工作得非常好...... 但对于 MFMessageComposeViewController 则不然。请在下面找到代码sn-p

        if (MFMessageComposeViewController.canSendText()) {
            let controller = MFMessageComposeViewController()
            controller.body = “Message Body”
            controller.messageComposeDelegate = self
            controller.modalPresentationStyle = .fullScreen
            self.present(controller, animated: true, completion: nil)
            self.trackEvent(shareType: "SMS")
        }
    }

【问题讨论】：

我的回答对你没有帮助？
@Alex.Pinhasov 这很有帮助，但我不是在寻找自定义实现，我只是在检查我是否以错误的方式进行操作。但它似乎与MFMailComposeViewController 本身有问题。
@iGauravK 你能告诉我，你解决了这个问题吗？以及如何？
@UsamaAzam 由于模态演示样式在这种情况下不起作用，而且我不想要任何自定义转换，所以答案是否定的。

标签： swift ios13 mfmailcomposeviewcontroller xcode11 uimodalpresentationstyle

【解决方案1】：

虽然我无法回答您关于 *为什么不能将 .fullScreen 用于 MFMessageComposeViewController 的问题，但我可以告诉您，如果您实现自己的自定义转换，您将获得所需的行为。

这是您为视图控制器设置自定义转换的方式：

var customTransitionDelegate = CustomTransition(presentAnimation: CustomActionSheetPresentationTransition(), dismissAnimation: CustomActionSheetDismissalTransition())

 if (MFMessageComposeViewController.canSendText()) {
     let controller = MFMessageComposeViewController()
     controller.body = "Message Body"
     controller.messageComposeDelegate = self
     controller.modalPresentationStyle = .custom
     controller.transitioningDelegate = customTransitionDelegate
     self.present(controller, animated: true, completion: nil)
 }

您还应该遵守委托并检查结果以在用户单击取消后将其关闭：

    func messageComposeViewController(_ controller: MFMessageComposeViewController, didFinishWith result: MessageComposeResult) {
    switch result {
    case .cancelled:
        self.presentedViewController?.dismiss(animated: true, completion: nil)
    default: break
    }
}

表示逻辑

class CustomActionSheetPresentationTransition: NSObject, UIViewControllerAnimatedTransitioning {
private let duration = 0.6

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    guard let fromView = transitionContext.viewController(forKey: .from) else { return }
    guard let toView   = transitionContext.viewController(forKey: .to) else { return }

    var screenOffUp = CGAffineTransform()
    let container = transitionContext.containerView

    screenOffUp = CGAffineTransform(translationX: 0, y: -fromView.view.frame.height)
    toView.view.frame = CGRect(x: 0, y: UIScreen.main.bounds.height, width: fromView.view.frame.width, height: fromView.view.frame.height)

    toView.view.center.x = container.center.x
    container.addSubview(toView.view)

    UIView.animate(withDuration: duration, delay: 0.0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0.8, options: [], animations: {
        toView.view.transform = screenOffUp
    }, completion: { (success) in
        transitionContext.completeTransition(success)
    })
}

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
    return duration
}
}

解雇逻辑

class CustomActionSheetDismissalTransition: NSObject, UIViewControllerAnimatedTransitioning {
private let duration = 0.8

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
    return duration
}

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    guard let fromView = transitionContext.viewController(forKey: .from) else { return }
    let screenOffDown = CGAffineTransform(translationX: 0, y: fromView.view.frame.height)

    UIView.animate(withDuration: duration, delay: 0.0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0.8, options: [], animations: {
        fromView.view.transform = screenOffDown
    }, completion: { (success) in
        transitionContext.completeTransition(success)
    })
}

}

【讨论】：