UIViewControllerAnimatedTransitioning只能在其他時間運行？

Question

我一直在這個小時，不能理解我做錯了什麼。我已經按照我之前的Swift: Problems with custom UIView.transition?

所述符合UITabBarControllerDelegate來裝配自定義標籤欄控制器轉換。我沒有使用正常情節串聯板標籤欄按鈕，我通過編程方式切換了selectedIndex。我的問題是，只有這樣實現：

func tabBarController(_ tabBarController: UITabBarController, animationControllerForTransitionFrom fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? { 
     let animator = ModalTransition() 
     animator.fromView = fromVC.view 
     animator.toView = toVC.view 
     return animator 

    } 

指數的動畫和切換隻發生在隔一段時間。我有自定義按鈕來切換索引和其他時間，當我單擊切換按鈕時沒有任何反應。這是我的動畫：

// 
// ModalTransition.swift 
// Adventures In Design 
// 
// Created by Skylar Thomas on 8/28/17. 
// 

import UIKit 

class ModalTransition: NSObject, UIViewControllerAnimatedTransitioning { 

    weak var transitionContext: UIViewControllerContextTransitioning? 
    var fromView = UIView() 
    var toView = UIView() 
    var duration = 1.1 


    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval { 
     return 1 
    } 

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) { 

     let containerView = transitionContext.containerView 
     containerView.addSubview(toView) 
     containerView.sendSubview(toBack: toView) 

     print("ANIMATING") 

     UIView.animate(withDuration: duration, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 0.0, options: .curveLinear, animations: { 
      self.fromView.center.y += 900 

     }, completion: { 
      finished in 

      //only works every OTHER click 
      transitionContext.completeTransition(!transitionContext.transitionWasCancelled) 
      self.fromView.center.y -= 900 
     }) 


    } 
} 

這是什麼原因造成的？這是什麼

Answer 1

我認爲你不是分配你的toView和FromView。嘗試類似這樣的

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) { 
      let fromViewController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from)! 
      let toViewController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)! 

      let fromView = fromViewController.view 
      let toView = toViewController.view 
      let container = transitionContext.containerView 
      container.addSubview(toView!) 
      // Replace your animations here 
toView?.frame = transitionContext.finalFrame(for: toViewController) 
     toView?.alpha = 0 
     let duration = self.transitionDuration(using: transitionContext) 
     UIView.animate(withDuration: duration, delay: 0, options: .curveEaseInOut, animations: { 
      toView?.alpha = 1 
      fromView?.alpha = 0 
     }, completion: { finished in 
      toView?.alpha = 1.0 
      fromView?.alpha = 1 
      fromView?.removeFromSuperview() 
      transitionContext.completeTransition(true) 

     }) 

     }