ios - 自定义过渡动画在关闭时不调用 VC 生命周期方法

Question

所以我构建了一个自定义呈现过渡动画，一切似乎都运行良好，除了 View Controller 生命周期方法没有在关闭时被调用。

在呈现 Controller 之前，我使用 UIModalPresentationCustom 样式将呈现的 VC 保留在 View 层次结构中，但是一旦我关闭呈现的 VC，我的呈现 Controller 就不会调用 viewWillAppear 和 viewDidAppear。我是否缺少需要显式调用才能触发这些方法的步骤？我知道手动调用这些方法不是正确的解决方案。

这是我的解散动画代码。我基本上是在为表单覆盖 View 设置动画，以在关闭时缩小到 Collection View 单元格的大小。

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

    UICollectionView *destinationCollectionView = toCollectionViewController.collectionView;
    UICollectionViewCell *destinationCollectionViewCell = [self _destinationCellFromContext:transitionContext];
    UIView *containerView = transitionContext.containerView;

    // Calculate frames    
    CGRect startFrame = fromEventDetailViewController.detailContainerView.frame;
    CGRect endFrame = [destinationCollectionView convertRect:destinationCollectionViewCell.frame toView:containerView];

    // Add overlay
    UIView *overlayView = [UIView new];
    overlayView.backgroundColor = [UIColor overlayBackground];
    overlayView.frame = containerView.bounds;
    overlayView.alpha = 1.0f;
    [containerView addSubview:overlayView];

    // Add fake detail container view
    UIView *fakeContainerView = [UIView new];
    fakeContainerView.backgroundColor = fromEventDetailViewController.detailContainerView.backgroundColor;
    fakeContainerView.frame = startFrame;
    [containerView addSubview:fakeContainerView];

    // Hide from view controller
    fromEventDetailViewController.view.alpha = 0.0f;

    [UIView animateWithDuration:[self transitionDuration:transitionContext] delay:0.0f usingSpringWithDamping:0.75f initialSpringVelocity:0.2f options:UIViewAnimationOptionCurveEaseOut animations:^{
        fakeContainerView.frame = endFrame;
        fakeContainerView.backgroundColor = [UIColor eventCellBackground];

        overlayView.alpha = 0.0f;
    } completion:^(BOOL finished) {
        [fromEventDetailViewController.view removeFromSuperview];
        [overlayView removeFromSuperview];
        [fakeContainerView removeFromSuperview];

        [transitionContext completeTransition:YES];
    }];
}

Answer 1

另一种解决方案可能是使用beginAppearanceTransition: 和endAppearanceTransition:。根据文档:

If you are implementing a custom container controller, use this method to tell the child that its views are about to appear or disappear. Do not invoke viewWillAppear:, viewWillDisappear:, viewDidAppear:, or viewDidDisappear: directly.

以下是我如何使用它们:

- (void)animationEnded:(BOOL)transitionCompleted
{
    if (!transitionCompleted)
    {
        _toViewController.view.transform = CGAffineTransformIdentity;
    }
    else
    {
        [_toViewController endAppearanceTransition];
    }
}

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

    [toViewController beginAppearanceTransition:YES animated:YES];
    // ... other code
}

但我仍然认为自定义模态展示不这样做很奇怪。