如何防止使用popViewController自定义过渡时关闭键盘

Question

要以全视图提供交互弹出手势，我在控制器中有一个UIPanGestureRecognizer，通过它我们可以在视图控制器中的任意位置从左向右滑动以弹出控制器，而不是使用默认的NavigationController弹出手势。

[当我在视图中打开键盘的状态下使用手势时，键盘也因交互而关闭（在默认的NavigationController弹出手势下不发生），这看起来很奇怪。

   func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
     if operation == .pop {
        return PopControllerTransition()//My transition
    }
    return nil
}

如何通过自定义弹出过渡在弹出viewController时防止键盘消失。

  //transition code
  func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    let containerView = transitionContext.containerView
    let fromController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from)!
    let toController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)!

    toController.view.transform = CGAffineTransform(translationX: -(toController.view.bounds.width/3), y: 0)
    containerView.insertSubview(toController.view, belowSubview: fromController.view)

    let view = GradientView(frame: containerView.frame)
    view.horizontal = true
    view.backgroundColor = UIColor.clear
    view.transform = CGAffineTransform(translationX: -toController.view.bounds.width, y: 0)
    view.gradientLayer.colors = [UIColor(white: 0.0, alpha: 0.2).cgColor, UIColor(white: 0.0, alpha: 0.5).cgColor]
    containerView.insertSubview(view, belowSubview: fromController.view)

    let duration = transitionDuration(using: transitionContext)

    UIView.animate(withDuration: duration, animations: {
        toController.view.transform = .identity
        fromController.view.transform = CGAffineTransform(translationX: fromController.view.bounds.width, y: 0)
        view.transform = .identity
        view.alpha = 0.0
    }) { (finish) in
        if !transitionContext.transitionWasCancelled {
            fromController.view.removeFromSuperview()
        }
        view.removeFromSuperview()
        transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
    }
}

Answer 1

所以我注意到，iOS 13上的键盘转换与iOS 12上的键盘转换不同，所以我不得不像这样手动进行：

    let animations: () -> Void = {
        fromView.frame.origin.x += fromView.bounds.width
        toView.frame.origin.x += fromView.bounds.width

        // Keyboard behavior changed on iOS 13. It dismisses ignoring transition
        // so need to fix that manually.
        if #available(iOS 13.0, *) {
            let keyboardWindow = UIApplication.shared.windows
                .first { String(describing: type(of: $0)) == "UIRemoteKeyboardWindow" }

            if let keyboardWindow = keyboardWindow, let keyboardImage = keyboardWindow.getImage() {
                let imageView = UIImageView(image: keyboardImage)
                keyboardWindow.addSubview(imageView)
                keyboardWindow.frame.origin.x += keyboardWindow.frame.width
            }
        }
    }

您可以检查我的执行情况-https://github.com/APUtils/Animators/blob/master/Animators/Classes/Right%20Slide%20Animation/RightSlideOutAnimator.swift