iOS 7 - 带有 UIViewcontrollerAnimatedTransitioning 的模态弹出窗口

Question

我正在尝试使用 UIViewcontrollerAnimatedTransitioning 呈现带有动画的 PopUp ViewController。我已经创建了一个从 TableViewCell 到我的 Viewcontroller 的 Modal Segue

在 PopupPresentAnimationController（实现 UIViewcontrollerAnimatedTransitioning）中我有

-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];

    [fromViewController addChildViewController:toViewController];
    toViewController.view.frame = fromViewController.view.frame;
    [fromViewController.view addSubview:toViewController.view];

    [toViewController didMoveToParentViewController:fromViewController];

    NSTimeInterval duration = [self transitionDuration:transitionContext];

    [UIView animateWithDuration:duration delay:0.0 usingSpringWithDamping:0.6 initialSpringVelocity:0.0 options:UIViewAnimationOptionCurveLinear animations:^{
        fromViewController.view.alpha = 0.5;
    } completion:^(BOOL finished) {
        fromViewController.view.alpha = 1.0;
        [transitionContext completeTransition:YES];
    }];
}

PopUpViewController 的背景为黑色，不透明度为 50%，当它出现所有“工作”但动画结束后，屏幕变黑。

更新 1：

UIViewController *fromViewController =[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIView *container = [transitionContext containerView];

    CGRect initialFrame = toViewController.view.frame;
    initialFrame.origin.y = toViewController.view.frame.size.height;

    toViewController.view.frame = initialFrame;
    [container insertSubview:toViewController.view aboveSubview:fromViewController.view];

    NSTimeInterval duration = [self transitionDuration:transitionContext];

    [UIView animateWithDuration:duration delay:0 options:0 animations:^{
        CGRect newFrame = toViewController.view.frame;
        newFrame.origin.y = 0;
        toViewController.view.frame = newFrame;
    } completion:^(BOOL finished) {
        [transitionContext completeTransition:YES];
    }];

更新 2 在 prepareForSegue 我添加了以下行

controller.modalPresentationStyle = UIModalPresentationCustom; // controller is the destination

有了这条线，黑色就不再是黑色了！

Answer 1

您遇到的问题是将toViewController 添加到fromViewController。当动画结束时，toViewController 被删除，而你的 fromViewController 也被删除。处理这个问题的正确方法是使用上下文提供的容器视图：

UIView *container = [transitionContext containerView];

这是一个如何进行弹出转换的示例：

-(void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
  UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
  UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
  UIView *container = [transitionContext containerView];

  if (!self.beingDismissed) {
    //Make controller hidden so it can slide in
    CGRect initialFrame = toViewController.view.frame;
    initialFrame.origin.y = toViewController.view.frame.size.height;

    toViewController.view.frame = initialFrame;
    [container insertSubview:toViewController.view aboveSubview:fromViewController.view];
  }
  [UIView animateKeyframesWithDuration:0.5 delay:0 options:0 animations:^{
    if (!self.beingDismissed) {
        //Show view controller
        CGRect newFrame = toViewController.view.frame;
        newFrame.origin.y = 0;
        toViewController.view.frame = newFrame;
    } else {
        //Hide view controller
        CGRect newFrame = fromViewController.view.frame;
        newFrame.origin.y = fromViewController.view.frame.size.height;
        fromViewController.view.frame = newFrame;
    }
  } completion:^(BOOL finished) {
    [transitionContext completeTransition:finished];
  }];
}