UICollectionViewCell 中子视图的正确转换答案

【问题标题】：Correct transition of subviews in UICollectionViewCellUICollectionViewCell 中子视图的正确转换
【发布时间】：2014-11-18 01:58:01
【问题描述】：

我正在使用 layoutToLayout 导航过渡 (useLayoutToLayoutNavigationTransitions)，但动画不流畅；在过渡期间，单元格的子视图会奇怪地跳来跳去：

可能出了什么问题？

我的 collectionviewcell 类如下所示：

private class PageCell : UICollectionViewCell {
    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    var viewController : UIViewController? {
        willSet {
            for view in self.contentView.subviews as [UIView] {
                view.removeFromSuperview()
            }
        }

        didSet {
            if let view = viewController?.view {
                view.frame = self.contentView.bounds
                self.contentView.addSubview(view)
                self.contentView.autoresizingMask = .FlexibleHeight | .FlexibleWidth;
                view.autoresizingMask = .FlexibleHeight | .FlexibleWidth;
            }
        }
    }
}

【问题讨论】：

标签： swift uicollectionview uicollectionviewcell

【解决方案1】：

我通过使用TLTransitionLayout 转换到其他布局解决了这个问题。它使动画对于更复杂的单元格看起来更好，因为它没有使用核心动画。

该方法还与useLayoutToLayoutNavigationTransitions 兼容，因此您可以获得所有不错的东西，例如将新导航项推送到导航栏等（不过我只在 iOS8 上测试过）。

以下是我的步骤：

1。有一个从一个 UICollectionViewController 到另一个 UICollectionViewController 的 layoutToLayout 过渡：

DetailViewController *detail = [[DetailViewController alloc] init];
detail.useLayoutToLayoutNavigationTransitions = YES;
[self.navigationController pushViewController:detail animated:YES];

...UICollectionViewController 子类中的其他地方...

- (UICollectionViewTransitionLayout *)collectionView:(UICollectionView *)collectionView transitionLayoutForOldLayout:(UICollectionViewLayout *)fromLayout newLayout:(UICollectionViewLayout *)toLayout
{
    NSArray *supplementaryKinds = @[]; // optional supplementary view kinds
    TLTransitionLayout *layout = [[TLTransitionLayout alloc] initWithCurrentLayout:fromLayout nextLayout:toLayout supplementaryKinds:supplementaryKinds];
    return layout;
}

2。有一个 `UINavigationControllerDelegate` 在某处实现此方法：

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

    if (operation == UINavigationControllerOperationPop) {
        return [[PopLayoutToLayoutAnimator alloc] init];
    }
    
    return nil;
}

3。实现动画师：

#import "TTProfileDetailPushAnimator.h"
#import <TLTransitionLayout.h>

@implementation TTProfileDetailPushAnimator

- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
    return 0.5;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    UICollectionViewController *toViewController;
    toViewController = (UICollectionViewController *)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    NSAssert([toViewController isKindOfClass:[UICollectionViewController class]], @"must be collection view controller");
    NSAssert(toViewController.useLayoutToLayoutNavigationTransitions, @"expecting layoutToLayout transition!");

    [[transitionContext containerView] addSubview:toViewController.view];

    UICollectionViewLayout *toLayout = toViewController.collectionViewLayout;
    UICollectionView *toCollectionView = toViewController.collectionView;
    NSTimeInterval duration = [self transitionDuration:transitionContext];
    
    UICollectionViewLayoutInteractiveTransitionCompletion completionBlock = ^(BOOL completed, BOOL finished) {
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    };

    TLTransitionLayout *layout;
    layout = (TLTransitionLayout *)[toCollectionView transitionToCollectionViewLayout:toLayout
                                                                             duration:duration
                                                                               easing:CubicEaseInOut
                                                                           completion:completionBlock];

    CGPoint toOffset = [toCollectionView toContentOffsetForLayout:layout
                                                       indexPaths:[toCollectionView indexPathsForSelectedItems]
                                                        placement:TLTransitionLayoutIndexPathPlacementCenter];
    
    layout.toContentOffset = toOffset;
}


@end

#import "TTProfileDetailPopAnimator.h"
#import <TLTransitionLayout.h>

@implementation TTProfileDetailPopAnimator

- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
    return 0.5;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    UICollectionViewController* toViewController;
    toViewController = (UICollectionViewController *)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UICollectionViewController* fromViewController;
    fromViewController = (UICollectionViewController *)[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    
    NSAssert([toViewController isKindOfClass:[UICollectionViewController class]], @"toVC must be collection view controller");
    NSAssert([fromViewController isKindOfClass:[UICollectionViewController class]], @"fromVC must be collection view controller");
    NSAssert(fromViewController.useLayoutToLayoutNavigationTransitions, @"expecting layoutToLayout transition!");

    [[transitionContext containerView] insertSubview:toViewController.view aboveSubview:fromViewController.view];
    
    UICollectionViewLayout *toLayout = toViewController.collectionViewLayout;
    UICollectionView *toCollectionView = toViewController.collectionView;
    NSTimeInterval duration = [self transitionDuration:transitionContext];
    
    UICollectionViewLayoutInteractiveTransitionCompletion completionBlock = ^(BOOL completed, BOOL finished) {
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    };
    
    TLTransitionLayout *layout;
    layout = (TLTransitionLayout *)[toCollectionView transitionToCollectionViewLayout:toLayout
                                                                             duration:duration
                                                                               easing:CubicEaseInOut
                                                                           completion:completionBlock];

    CGPoint toOffset = [toCollectionView toContentOffsetForLayout:layout
                                                       indexPaths:[toCollectionView indexPathsForVisibleItems]
                                                        placement:TLTransitionLayoutIndexPathPlacementCenter];
    layout.toContentOffset = toOffset;
}

@end

【讨论】：

这似乎是一个很棒的解决方案。你有一个正在工作的项目吗？你还能对单元格的子视图使用自动布局吗？
@BobdeGraaf 是的，这在我的应用程序“Inkmonkey”itunes.apple.com/us/app/inkmonkey-the-tattoo-network/… 中工作（在用户个人资料屏幕中）。我的单元格包含 UIViewController 视图。
我注意到了两个缺点：TLTransitionLayout 有时（非常罕见）由于某种原因而崩溃，我还不知道为什么。此外，添加一个大的视图层次结构（如 UIViewController 视图作为 UICollectionViewCell 的子视图）对于 UIKit 来说非常繁重，并且会使应用程序在旧设备上感觉非常迟钝。 Iphone6 和 6+ 处理得很好。
是的，我也在使用自动布局
stefreak，使用您的确切代码，push animator 可以完美运行，但 pop 动画代码总是崩溃，知道为什么吗？你还说你使用自动布局。所以我假设你在某个地方为约束设置动画？你能指出我正确的方向（或提供一些代码）我需要在哪里为我的 collectionviewcell 的子视图的自动布局约束设置动画吗？ :)

1。有一个从一个 UICollectionViewController 到另一个 UICollectionViewController 的 layoutToLayout 过渡：

2。有一个 UINavigationControllerDelegate 在某处实现此方法：

3。实现动画师：

2。有一个 `UINavigationControllerDelegate` 在某处实现此方法：