Question

我正在使用自定义UIPresentationController模态呈现视图。呈现视图后，呈现的视图中的第一个文本字段将成为第一响应者，并显示键盘。为了确保视图仍然可见，我将其向上移动。但是，当我这样做时，frameOfPresentedViewInContainerView不再与视图的实际框架匹配。因此，当我点击视图时，该视图将被关闭，因为在presentingView顶部的backgroundView上有一个tapGestureRecogziner。如何通知presentingController PresentedView的帧/位置已更改？

在UIPresentationController中：

    override var frameOfPresentedViewInContainerView: CGRect {
        var frame =  CGRect.zero
        let safeAreaBottom = self.presentingViewController.view.safeAreaInsets.bottom
        guard let height = presentedView?.frame.height else { return frame }
        if let containerBounds = containerView?.bounds {
            frame = CGRect(x: 0,
                           y: containerBounds.height - height - safeAreaBottom,
                           width: containerBounds.width,
                           height: height + safeAreaBottom)
        }
        return frame
    }

    override func presentationTransitionWillBegin() {
        if let containerView = self.containerView, let coordinator = presentingViewController.transitionCoordinator {
            containerView.addSubview(self.dimmedBackgroundView)
            self.dimmedBackgroundView.backgroundColor = .black
            self.dimmedBackgroundView.frame = containerView.bounds
            self.dimmedBackgroundView.alpha = 0
            coordinator.animate(alongsideTransition: { _ in
                self.dimmedBackgroundView.alpha = 0.5
            }, completion: nil)
        }
    }

以模态呈现视图：

            let overlayVC = CreateEventViewController()

            overlayVC.transitioningDelegate = self.transitioningDelegate
            overlayVC.modalPresentationStyle = .custom
            self.present(overlayVC, animated: true, completion: nil)

出现键盘时的动画（在显示的视图中）：

    @objc func animateWithKeyboard(notification: NSNotification) {
        let userInfo = notification.userInfo!
        guard let keyboardHeight = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue.height,
            let duration = userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double,
            let curve = userInfo[UIResponder.keyboardAnimationCurveUserInfoKey] as? UInt else {
                return
        }

        // bottomContraint is the constraint that pins content to the bottom of the superview.
        let moveUp = (notification.name == UIResponder.keyboardWillShowNotification)
        bottomConstraint.constant = moveUp ? (keyboardHeight) : originalBottomValue

        let options = UIView.AnimationOptions(rawValue: curve << 16)
        UIView.animate(withDuration: duration, delay: 0,
                       options: options,
                       animations: {
                        self.view.layoutIfNeeded()
        }, completion: nil)
    }

Answer 1

从Apple文档中获取：

UIKit在操作过程中多次调用此方法。演示文稿，因此您的实现应返回相同的框架每次矩形。不要使用此方法来更改您的查看层次结构或执行其他一次性任务。

AFAIK，如果您通过此变量指定框架，建议在整个演示过程中不要更改它。如果您打算使用这些框架，请不要指定此变量，而要在动画师中手动处理所有更改

使用自定义模式演示时如何更新frameOfPresentedViewInContainerView？

1 个答案: