我一直在按照一些教程创建自定义动画，同时从一个 View 过渡到另一个 View 。

我的测试项目使用来自 here 的自定义 segue工作正常，但有人告诉我不再鼓励在自定义 segue 中制作自定义动画，我应该使用 UIViewControllerAnimatedTransitioning。

我遵循了几个使用此协议(protocol)的教程，但它们都是关于模态表示的(例如 this tutorial)。

我正在尝试做的是在导航 Controller 树中推送 segue，但是当我尝试用 show(推送)segue 做同样的事情时，它不再起作用了。

请告诉我在导航 Controller 中执行从一个 View 到另一个 View 的自定义过渡动画的正确方法。

无论如何我可以对所有过渡动画使用一种方法吗？如果有一天我想做同样的动画，但最终不得不将代码复制两次以处理模态与 Controller 的转换，那会很尴尬。

最佳答案

要使用导航 Controller (UINavigationController) 进行自定义转换，您应该:

• 定义您的 View Controller 以符合 UINavigationControllerDelegate 协议(protocol)。例如，您可以在 View Controller 的 .m 文件中有一个私有(private)类扩展，指定遵守此协议(protocol):

  @interface ViewController () <UINavigationControllerDelegate>
  
  @end
  

• 确保您确实将 View Controller 指定为导航 Controller 的委托(delegate):

  - (void)viewDidLoad {
      [super viewDidLoad];
  
      self.navigationController.delegate = self;
  }
  

• 在您的 View Controller 中实现 animationControllerForOperation:

  - (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
                                    animationControllerForOperation:(UINavigationControllerOperation)operation
                                                 fromViewController:(UIViewController*)fromVC
                                                   toViewController:(UIViewController*)toVC
  {
      if (operation == UINavigationControllerOperationPush)
          return [[PushAnimator alloc] init];
  
      if (operation == UINavigationControllerOperationPop)
          return [[PopAnimator alloc] init];
  
      return nil;
  }
  

• 为推送和弹出动画实现动画师，例如:

  @interface PushAnimator : NSObject <UIViewControllerAnimatedTransitioning>
  
  @end
  
  @interface PopAnimator : NSObject <UIViewControllerAnimatedTransitioning>
  
  @end
  
  @implementation PushAnimator
  
  - (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
  {
      return 0.5;
  }
  
  - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
  {
      UIViewController* toViewController   = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
  
      [[transitionContext containerView] addSubview:toViewController.view];
  
      toViewController.view.alpha = 0.0;
  
      [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
          toViewController.view.alpha = 1.0;
      } completion:^(BOOL finished) {
          [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
      }];
  }
  
  @end
  
  @implementation PopAnimator
  
  - (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
  {
      return 0.5;
  }
  
  - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
  {
      UIViewController* toViewController   = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
      UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
  
      [[transitionContext containerView] insertSubview:toViewController.view belowSubview:fromViewController.view];
  
      [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
          fromViewController.view.alpha = 0.0;
      } completion:^(BOOL finished) {
          [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
      }];
  }
  
  @end
  

  这确实是淡入淡出过渡，但您可以根据需要随意自定义动画。

• 如果您想处理交互式手势(例如，从左向右滑动以弹出的原生手势)，您必须实现一个交互 Controller :

  • 为交互 Controller (符合 UIViewControllerInteractiveTransitioning 的对象)定义一个属性:

    @property (nonatomic, strong) UIPercentDrivenInteractiveTransition *interactionController;
    

    这个 UIPercentDrivenInteractiveTransition 是一个很好的对象，它根据手势的完成程度完成更新自定义动画的繁重工作。

  • 将手势识别器添加到您的 View 中。在这里，我只是实现左手势识别器来模拟弹出:

    UIScreenEdgePanGestureRecognizer *edge = [[UIScreenEdgePanGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipeFromLeftEdge:)];
    edge.edges = UIRectEdgeLeft;
    [view addGestureRecognizer:edge];
    

  • 实现手势识别处理程序:

    /** Handle swipe from left edge
     *
     * This is the "action" selector that is called when a left screen edge gesture recognizer starts.
     *
     * This will instantiate a UIPercentDrivenInteractiveTransition when the gesture starts,
     * update it as the gesture is "changed", and will finish and release it when the gesture
     * ends.
     *
     * @param   gesture       The screen edge pan gesture recognizer.
     */
    
    - (void)handleSwipeFromLeftEdge:(UIScreenEdgePanGestureRecognizer *)gesture {
        CGPoint translate = [gesture translationInView:gesture.view];
        CGFloat percent   = translate.x / gesture.view.bounds.size.width;
    
        if (gesture.state == UIGestureRecognizerStateBegan) {
            self.interactionController = [[UIPercentDrivenInteractiveTransition alloc] init];
            [self popViewControllerAnimated:TRUE];
        } else if (gesture.state == UIGestureRecognizerStateChanged) {
            [self.interactionController updateInteractiveTransition:percent];
        } else if (gesture.state == UIGestureRecognizerStateEnded) {
            CGPoint velocity = [gesture velocityInView:gesture.view];
            if (percent > 0.5 || velocity.x > 0) {
                [self.interactionController finishInteractiveTransition];
            } else {
                [self.interactionController cancelInteractiveTransition];
            }
            self.interactionController = nil;
        }
    }
    

  • 在您的导航 Controller 委托(delegate)中，您还必须实现 interactionControllerForAnimationController 委托(delegate)方法

    - (id<UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController
                             interactionControllerForAnimationController:(id<UIViewControllerAnimatedTransitioning>)animationController {
        return self.interactionController;
    }
    

如果你用谷歌搜索“UINavigationController 自定义转换教程”，你会得到很多结果。或查看 WWDC 2013 Custom Transitions video .

关于ios - 导航 Controller 自定义过渡动画，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26569488/