albincr / collectionviewanimation

Animation for insert, delete and move item.

Animating insert/delete/move item in UICollectionView

After I create UIView refactor/destruct extension, I think here is a good scene. Thanks for Animating Collection Views, I get a lot of help from this article.

Installation and Usage

Drag SDEFlowLayoutWithAnimation.swift and UIViewRefactorAndDestructExtension.swift into your project.

Set UICollectionView's collectionViewLayout to SDEFlowLayoutWithAnimation in your storyboard or in your code.

Insert Animation:

In CollectionView's delegate, override the follow method, assume that animationLayout is collectionView's layout.

override func collectionView(collectionView: UICollectionView, willDisplayCell cell: UICollectionViewCell, forItemAtIndexPath indexPath: NSIndexPath) {
    if animationLayout != nil{
        let filteredItems = animationLayout!.insertedItemsToAnimate.filter({
            element in
            return element.section == indexPath.section && element.item == indexPath.item
        })
        if filteredItems.count > 0{
            cell.refactor()
        }
    }
}

Delete Animation:

......//update the data source.
let deletedIndexPath = ...
let deletedCell = self.collectionView?.cellForItemAtIndexPath(deletedIndexPath)
let animationTime: NSTimeInterval = 0.5
deletedCell?.destructWithTime(animationTime)
self.collectionView?.performSelector("deleteItemsAtIndexPaths:", withObject: [deletedIndexPath], afterDelay: animationTime)

Move Animation:

Just move, the rest work is done automatically. If you don't like this animation, I like default animation actually, go to SDEFlowLayoutWithAnimation.swift and delete the relative code, there are comments to tell you how do it.

Issue:

Insert animation is interrupted always. It should be like this:

Move animation have the same problem. I don't known why. I guess because of layout animation behind it. I try to use Core Animation instead of UIView block animation. It works. But when you insert several cells, it's also interrupted, at last, animation is totally removed. I try to put refactor method in main queue, it works fine also. But it bring a little trouble: before refactor animation, cells behind it shake, I don't want this. There is no prefect way for now. If you find the way, please pull a request or email me, [email protected].

Multiple Cells Action

In the sample, I just test for single cell action, test for multiple cells action is not completed. There may be something wrong for multiple cells action.

Requirements

• Swift 2.0+

UICollectionView 插入/删除/移动项目动画

在 UIView refacot/destruct 动画扩展完成之后，我想这个场景是比较合适的。感谢 Collection View 动画，我最初的想法是从这篇文章得到的，虽然我这里的手法其实和文章里的不同，但帮助我解决了一半问题。

安装和使用

把 SDEFlowLayoutWithAnimation.swift 和 UIViewRefactorAndDestructExtension.swift 这两个文件拖进你的项目里就好了。

设置collectionViewLayout: 在你的 storyboard 里或代码里设置都行。不会的话，示例工程里是通过代码设置的，还不会不要问我，先去学习吧。

Insert Animaton:

在 CollectionView 的代理里，重写下面的方法，假设animationLayout是这个 CollectionView 的 layout:

override func collectionView(collectionView: UICollectionView, willDisplayCell cell: UICollectionViewCell, forItemAtIndexPath indexPath: NSIndexPath) {
    if animationLayout != nil{
        let filteredItems = animationLayout!.insertedItemsToAnimate.filter({
            element in
            return element.section == indexPath.section && element.item == indexPath.item
        })
        if filteredItems.count > 0{
            cell.refactor()
        }
    }
}

Delete Animation:

当 cell 不在屏幕上的时候就没必要执行删除动画了，示例里是这么写的。

......//记得先更新数据源
let deletedIndexPath = ...
let deletedCell = self.collectionView?.cellForItemAtIndexPath(deletedIndexPath)
let animationTime: NSTimeInterval = 0.5
deletedCell?.destructWithTime(animationTime)
self.collectionView?.performSelector("deleteItemsAtIndexPaths:", withObject: [deletedIndexPath], afterDelay: animationTime)

Move Animation:

移动就好了，剩下的事情会自动完成。如果你不喜欢这个效果，实际上我更喜欢默认的效果，你可以去 SDEFlowLayoutWithAnimation.swift 里删除相关代码，我写了注释告诉你删除哪些代码。

缺陷：

目前的插入动画有点问题，这个动画总是被打断，没有按照预期的方式完成，移动动画也有相同的问题。我不知道为什么，猜测是由于后续的布局动画造成的。本来是用 UIView block animation 实现的，我尝试用 Core Animation 来实现，不会被打断，但是在添加几个 cell 后发现，动画也开始被打断，到最后动画根本就不会出现。我后来意识到是不是没有放在主线程里，尝试后发现再也不会被打断了，但是也带来一点点副作用，在重组动画开始前，后面位置的 cells 会晃动，我不是我想要的，当然主要是因为晃动的样子像卡壳了，目前没找到完美的解决办法。如果你找到了方法，麻烦提个请求，或者来介绍这个动画的博客下留言。

多 cell 操作

示例里我只针对单个 cell 进行了测试，多个 cells 的操作的测试并不完整，只稍微测试了删除多个 cell，目前工作正常。还有涉及 section 操作时没有测试。如果有这方面的需求，自己尝试下吧。

使用条件

• Swift 2.0+