Ios DiffableDataSource-是否有办法限制只能在同一节中执行重新排序？

在中，苹果展示了一个关于如何使用

DiffableDataSource

ReorderableListViewController.swift

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是否有办法限制只能在同一区段内执行重新排序？

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在

reorderingHandlers.canReorderItem

中我们做不了什么，因为闭包参数

item

指的是我们正在拖动的当前源项。没有关于目标项的信息，我们可以将其与进行比较以决定是否返回true或false。

对于您的数据源来说，这种行为不是问题。这是你的代表的问题

你可以用 确定是否允许移动

func collectionView(_ collectionView: UICollectionView, 
targetIndexPathForMoveFromItemAt originalIndexPath: IndexPath, 
         toProposedIndexPath proposedIndexPath: IndexPath) -> IndexPath {

    let sourceSection = sourceIndexPath.section
    let destSection = proposedDestinationIndexPath.section

    var destination = proposedDestinationIndexPath

    if destSection < sourceSection {
        destination = IndexPath(item: 0, section: sourceSection)
    } else if destSection > sourceSection {
        destination = IndexPath(item: self.backingStore[sourceSection].count-1, section: sourceSection)
    }

    return destination
}

func collectionView（collectionView:UICollectionView，
targetIndexPathForMoveFromItemAt originalIndexPath:IndexPath，
toProposedIndexPath proposedIndexPath:IndexPath）->IndexPath{
让sourceSection=sourceIndexPath.section
设destSection=proposedDestinationIndexPath.section
var destination=proposedDestinationIndexPath
如果destSectionsourceSection，则为else{
destination=IndexPath（项：self.backingStore[sourceSection].count-1，section:sourceSection）
}
返回目的地
}

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这会将项目的移动限制到其自己的部分。

您也可以在委托方法collectionView（\uU9:targetIndexPathForMoveFromItemAt:TopProposedIndexPath:）中使用此类记录

我在Matt Neuburg的《编程iOS 14》一书中读到了这一点，效果很好：）

func collectionView(_ collectionView: UICollectionView, 
targetIndexPathForMoveFromItemAt originalIndexPath: IndexPath, 
         toProposedIndexPath proposedIndexPath: IndexPath) -> IndexPath {

    let sourceSection = sourceIndexPath.section
    let destSection = proposedDestinationIndexPath.section

    var destination = proposedDestinationIndexPath

    if destSection < sourceSection {
        destination = IndexPath(item: 0, section: sourceSection)
    } else if destSection > sourceSection {
        destination = IndexPath(item: self.backingStore[sourceSection].count-1, section: sourceSection)
    }

    return destination
}

func collectionView(_ collectionView: UICollectionView, targetIndexPathForMoveFromItemAt originalIndexPath: IndexPath, toProposedIndexPath proposedIndexPath: IndexPath) -> IndexPath {
        if originalIndexPath.section != proposedIndexPath.section {
            return originalIndexPath
        }
        return proposedIndexPath
}