Ios 如果不使用interactionController之类的辅助对象，如何在自定义pop转换中插入toViewController？

这是一个自定义的弹出式手势，用于

UINavigationController

，它不使用像

interactionController

这样的助手。pop转换完全是手动的，效果很好，只是当手势开始时，我需要在

fromViewController

下面插入

到ViewController

。由于此脚本现在已存在，因此只有在手势成功完成后才会显示

toViewController

这就是快照发挥作用的地方吗？我从来没用过。或者我应该将toViewController放入superview中，然后在手势完成后将其移除

func popPanGestureHandler(_ gesture: UIPanGestureRecognizer) {

    guard let fromViewController = currentViewController,
        let toViewController = previousViewController else {
        return
    }

    let translation: CGPoint = gesture.translation(in: gesture.view)
    let velocity: CGPoint = gesture.velocity(in: gesture.view)

    switch gesture.state {

    case .began:

        // insert toViewController here
        fromViewController.view.center = CGPoint(x: fromViewController.view.center.x + translation.x, y: fromViewController.view.center.y)
        gesture.setTranslation(CGPoint.zero, in: gesture.view)

    case .changed:

        fromViewController.view.center = CGPoint(x: fromViewController.view.center.x + translation.x, y: fromViewController.view.center.y)
        gesture.setTranslation(CGPoint.zero, in: gesture.view)

        // force finish
        if fromViewController.view.frame.origin.x > (fromViewController.view.frame.width / 3) * 2 {

            UIView.animate(withDuration: 0.2, delay: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
                fromViewController.view.frame.origin.x = fromViewController.view.frame.width
            }, completion: {
                (finished: Bool) in
                self.popViewController(animated: false)

            })

            gesture.isEnabled = false
            gesture.isEnabled = true

        }

    case .ended:

        // cancel
        if fromViewController.view.frame.origin.x < fromViewController.view.frame.width / 2 && velocity.x < 750 {

            UIView.animate(withDuration: 0.2, delay: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
                fromViewController.view.frame.origin.x = 0
            }, completion: {
                (finished: Bool) in
                self.dismiss(animated: true, completion: nil)
            })

            gesture.isEnabled = false
            gesture.isEnabled = true

        }

        // finish
        else if fromViewController.view.frame.origin.x >= fromViewController.view.frame.width / 2 {

            UIView.animate(withDuration: 0.2, delay: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
                fromViewController.view.frame.origin.x = fromViewController.view.frame.width
            }, completion: {
                (finished: Bool) in
                self.popViewController(animated: false)
            })

            gesture.isEnabled = false
            gesture.isEnabled = true

        }

        // finish
        else if velocity.x >= 750 {

            UIView.animate(withDuration: 0.2, delay: 0, options: UIViewAnimationOptions.curveEaseOut, animations: {
                fromViewController.view.frame.origin.x = fromViewController.view.frame.width
            }, completion: {
                (finished: Bool) in
                self.popViewController(animated: false)
            })

            gesture.isEnabled = false
            gesture.isEnabled = true

        }

    default:
        break

    }

}

func-popPanGestureHandler（uu手势：uipangestrerecognizer）{
来自ViewController的保护let=currentViewController，
让toViewController=previousViewController-else{
返回
}
let translation:CGPoint=signature.translation（in:signature.view）
让速度：CGPoint=手势.速度（in:手势.视图）
开关状态{
案例.开始：
//在此处插入视图控制器
fromViewController.view.center=CGPoint（x:fromViewController.view.center.x+translation.x，y:fromViewController.view.center.y）
手势.setTranslation（CGPoint.zero，in:手势.view）
案例。更改：
fromViewController.view.center=CGPoint（x:fromViewController.view.center.x+translation.x，y:fromViewController.view.center.y）
手势.setTranslation（CGPoint.zero，in:手势.view）
//强制完成
如果fromViewController.view.frame.origin.x>（fromViewController.view.frame.width/3）*2{
UIView.animate（持续时间：0.2，延迟：0，选项：UIViewAnimationOptions.curveEaseOut，动画：{
fromViewController.view.frame.origin.x=fromViewController.view.frame.width
}，完成日期：{
（完成：Bool）在
self.popViewController（动画：false）
})
signature.isEnabled=false
signature.isEnabled=true
}
案件结束：
//取消
如果fromViewController.view.frame.origin.x=fromViewController.view.frame.width/2，则为else{
UIView.animate（持续时间：0.2，延迟：0，选项：UIViewAnimationOptions.curveEaseOut，动画：{
fromViewController.view.frame.origin.x=fromViewController.view.frame.width
}，完成日期：{
（完成：Bool）在
self.popViewController（动画：false）
})
signature.isEnabled=false
signature.isEnabled=true
}
//完成
否则，如果速度.x>=750{
UIView.animate（持续时间：0.2，延迟：0，选项：UIViewAnimationOptions.curveEaseOut，动画：{
fromViewController.view.frame.origin.x=fromViewController.view.frame.width
}，完成日期：{
（完成：Bool）在
self.popViewController（动画：false）
})
signature.isEnabled=false
signature.isEnabled=true
}
违约：
打破
}
}