Question

我在网上等其他地方闲逛了，还没有找到解决方案。我在一个视图控制器上有一个UILongPressGestureRecognizer，它在UIView上执行动画，然后显示另一个视图控制器（如果用户在动画过程中没有移动手指）。当用户抬起手指时，我想关闭第二个视图控制器，但是我遇到了麻烦。

我当前的方法是将另一个UILongPressGestureRecognizer添加到第二个视图控制器，并在状态结束时关闭视图控制器；但是我不知道如何将两个手势识别器绑在一起，这样我才能在一个视图控制器中开始触摸，而在另一个视图控制器中结束。

我在下面附上了相关代码

在第一个View Controller中

   @objc private func pinAnimation(sender: UILongPressGestureRecognizer) {
    if let headerView = projectView.projectCollectionView.supplementaryView(forElementKind: UICollectionElementKindSectionHeader, at: IndexPath(row: 0, section: 0)) as? ProjectHeaderView {

        switch sender.state {
        case .began:
            let frame = headerView.pinButton.frame
            UIView.setAnimationCurve(.linear)

            UIView.animate(withDuration: 1, animations: {
                headerView.pinProgressView.frame = frame
            }, completion: { (_) in
                if (headerView.pinProgressView.frame == headerView.pinButton.frame) {
                    let notification = UINotificationFeedbackGenerator()
                    notification.notificationOccurred(.success)
                    let homeVC = HomeViewController()
                    self.present(homeVC, animated: true, completion: {

                        homeVC.longPress(sender)

                        let height = headerView.pinButton.frame.height
                        let minX = headerView.pinButton.frame.minX
                        let minY = headerView.pinButton.frame.minY
                        headerView.pinProgressView.frame = CGRect(x: minX, y: minY, width: 0, height: height)
                    })
                }
            })

        case .ended:
            //cancel current animation
            let height = headerView.pinProgressView.frame.height
            let minX = headerView.pinProgressView.frame.minX
            let minY = headerView.pinProgressView.frame.minY
            UIView.setAnimationCurve(.linear)
            UIView.animate(withDuration: 0.5) {
                headerView.pinProgressView.frame = CGRect(x: minX, y: minY, width: 0, height: height)
            }
        default:
            break
        }
    }
}

在第二个View Controller中

override func viewDidLoad() {
    super.viewDidLoad()
    let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(longPress(_:)))
    view.addGestureRecognizer(longPressRecognizer)
}

@objc func longPress(_ sender: UILongPressGestureRecognizer) {
    switch sender.state {
    case .ended:
        self.dismiss(animated: true, completion: nil)
    default:
        break
    }
}

任何帮助/指导将不胜感激！

Answer 1

我建议您使用委托模式：

为您的第一个ViewController创建委托

protocol FirstViewControllerDelegate {
    func longPressEnded() 
}

然后将delegate变量添加到您的第一个ViewController

class FirstViewController {
    var delegate: FirstViewControllerDelegate?
    ...
}

长按结束时代表的下一步呼叫方法

@objc private func pinAnimation(sender: UILongPressGestureRecognizer) {
    ...
    switch sender.state {
    case .began:
        ...
    case .ended:
        ...
        delegate?.longPressEnded()
    default:
        break
    }
}

之后，当您展示第二个ViewController时，将第一个ViewController的delegate设置为homeVC

let homeVC = HomeViewController()
self.delegate = homeVC

然后将该委托实现到第二个ViewController并定义长按结束时应该发生的情况

class HomeViewController: UIViewController, FirstViewControllerDelegate {
    ...
    func longPressEnded() {
        dismiss(animated: true, completion: nil)
    }
}

在UIViewControllers之间传递UILongPressGestureRecognizer

1 个答案: