ViewBrowler动画前Tabbar点击

Question

我有一个TabBarController有3个navigationController，其中每个都有一个相应的viewController：AViewController，BViewController和CViewController。首先一个有我想用viewDisappears时针对它运行的动画一个UIView元素：

UIView.animateWithDuration(duration, delay: 0.0, options: .CurveEaseOut, animations: { 

期间

...

override func viewWillDisappear(animated: Bool) { 

如果用户点击中的TabBar项目2或3，我想该动画首先发生，然后将用户带到项目＃2或＃3。

问题是，当用户点击一个不同的项目，在TabBarController此代码首先触发在我的ViewController一个

override func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem) { 

的viewwillDisappears前，然后我的动画不运行。

我应该在哪里放置我的动画，以便在用户转到tabbar中的其他项目之前运行它？

Answer 1

您可以从UITabBarControllerDelegate实现tabBarController:shouldSelectViewController:，返回false，播放您的动画，然后以编程方式更改选项卡。

Answer 2

你需要编写自己的UIViewControllerAnimatedTransitioning（https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewControllerAnimatedTransitioning_Protocol/）

试试这个代码：

TabBarController.swift

import UIKit 
class TabBarController: UITabBarController, UITabBarControllerDelegate { 

var buttons = [UIButton]() 

override func viewDidLoad() { 
    super.viewDidLoad() 
    self.delegate = self 

    var newViewControllers = [UIViewController]() 

    for index in 0..<2 { 
     let viewController = ViewController() 
     var tabBarItem = UITabBarItem() 

     switch index { 
     case 0: 
      viewController.view.backgroundColor = UIColor.blueColor() 
      viewController.label.textColor = UIColor.whiteColor() 
      tabBarItem = UITabBarItem(tabBarSystemItem: .More, tag: index) 
     case 1: 
      viewController.view.backgroundColor = UIColor.greenColor() 
      viewController.label.textColor = UIColor.blackColor() 
      tabBarItem = UITabBarItem(tabBarSystemItem: .Favorites, tag: index) 
     default: 
      break 
     } 

     viewController.label.text = "Text \(index)" 
     viewController.tabBarItem = tabBarItem 
     newViewControllers.append(viewController) 
     //tabBar.items![index] = tabBarItem 

    } 

    selectedIndex = 0 
    // = newViewControllers 
    setViewControllers(newViewControllers, animated: false) 
    // Do any additional setup after loading the view, typically from a nib. 
} 

func tabBarController(tabBarController: UITabBarController, animationControllerForTransitionFromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? { 
    let fromIndex = tabBarController.viewControllers!.indexOf(fromVC)! 
    let toIndex = tabBarController.viewControllers!.indexOf(toVC)! 

    let tabChangeDirection: TabOperationDirection = toIndex < fromIndex ? .Left : .Right 
    let transitionType = SDETransitionType.TabTransition(tabChangeDirection) 
    let slideAnimationController = SlideAnimationController(type: transitionType) 
    return slideAnimationController 

} 
} 

ViewController.swift

import UIKit 
class ViewController: UIViewController { 

let label = UILabel(frame: CGRect(x: 40, y: 60, width: 80, height: 40)) 

override func viewDidLoad() { 
    super.viewDidLoad() 
    view.addSubview(label) 
} 

var labelHidden = false { 
    willSet(value) { 
     if value { 
      self.label.frame.origin.y = -40 
     } else { 
      self.label.frame.origin.y = 60 
     } 
    } 
} 
} 

SlideAnimationController.swift（资源：https://github.com/seedante/iOS-ViewController-Transition-Demo）

import UIKit 

enum SDETransitionType{ 
case NavigationTransition(UINavigationControllerOperation) 
case TabTransition(TabOperationDirection) 
case ModalTransition(ModalOperation) 
} 

enum TabOperationDirection{ 
case Left, Right 
} 

enum ModalOperation{ 
case Presentation, Dismissal 
} 

class SlideAnimationController: NSObject, UIViewControllerAnimatedTransitioning { 

private var transitionType: SDETransitionType 

init(type: SDETransitionType) { 
    transitionType = type 
    super.init() 
} 

func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval { 
    return 0.3 
} 

func animateTransition(transitionContext: UIViewControllerContextTransitioning) { 

    guard let containerView = transitionContext.containerView(), fromVC = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey), toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey) else{ 
     return 
    } 

    let fromView = fromVC.view 
    let toView = toVC.view 

    var translation = containerView.frame.width 
    var toViewTransform = CGAffineTransformIdentity 
    var fromViewTransform = CGAffineTransformIdentity 

    switch transitionType{ 
    case .NavigationTransition(let operation): 
     translation = operation == .Push ? translation : -translation 
     toViewTransform = CGAffineTransformMakeTranslation(translation, 0) 
     fromViewTransform = CGAffineTransformMakeTranslation(-translation, 0) 
    case .TabTransition(let direction): 
     translation = direction == .Left ? translation : -translation 
     fromViewTransform = CGAffineTransformMakeTranslation(translation, 0) 
     toViewTransform = CGAffineTransformMakeTranslation(-translation, 0) 
    case .ModalTransition(let operation): 
     translation = containerView.frame.height 
     toViewTransform = CGAffineTransformMakeTranslation(0, (operation == .Presentation ? translation : 0)) 
     fromViewTransform = CGAffineTransformMakeTranslation(0, (operation == .Presentation ? 0 : translation)) 
    } 

    switch transitionType{ 
    case .ModalTransition(let operation): 
     switch operation{ 
     case .Presentation: containerView.addSubview(toView) 
     case .Dismissal: break 
     } 
    default: containerView.addSubview(toView) 
    } 

    toView.transform = toViewTransform 

    if let fromVC = fromVC as? ViewController { 
     UIView.animateWithDuration(0.3, delay: 0.0, options: .CurveEaseOut, animations: { 
      fromVC.labelHidden = true 
      }, completion: { 
       bool in 
       UIView.animateWithDuration(self.transitionDuration(transitionContext), animations: { 
        fromView.transform = fromViewTransform 
        toView.transform = CGAffineTransformIdentity 
        }, completion: { finished in 
         fromView.transform = CGAffineTransformIdentity 
         toView.transform = CGAffineTransformIdentity 

         let isCancelled = transitionContext.transitionWasCancelled() 
         transitionContext.completeTransition(!isCancelled) 

         fromVC.labelHidden = false 
       }) 
     }) 
    } 
} 
}