Swift OSX - 通过拖放重新排列 NSCollectionView 无效

Question

我正在尝试重新排列 NSCollectionView 中的项目，但它不起作用。它不会将某些委托方法调用为 validate drop 和 accept drop。它调用 func collectionView(_ collectionView: NSCollectionView, pasteboardWriterForItemAt indexPath: IndexPath) -> NSPasteboardWriting? 或 func collectionView(_ collectionView: NSCollectionView, writeItemsAt indexPaths: Set<IndexPath>, to pasteboard: NSPasteboard) -> Bool，但之后不会调用其他方法。

我认为问题是我的机器人能够为拖放注册正确的类型，因为当我在集合视图中移动项目时，它没有显示可以放置项目的地方并且在我放下它之后，物品会弹回原来的位置。

代码如下：

FotoProdutoLojaCollectionViewItem.swift 导入 Cocoa

class FotoProdutoLojaCollectionViewItem: NSCollectionViewItem {

    @IBOutlet weak var fotoProdutoLojaImageView: NSImageView!
    @IBOutlet weak var fotoCapaImageView: NSImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        fotoCapaImageView.isHidden = true
    }

}

CollectionView 的项目

func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {

        var item = NSCollectionViewItem()

        item = collectionView.makeItem(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "FotoProdutoLojaCollectionViewItem"), for: indexPath)

        let fotosProdutoLojaCollectionViewItem = item as! FotoProdutoLojaCollectionViewItem

        produtoLoja?.fotos[indexPath.item].foto?.getDataInBackground(block: {
            (data: Data?, error: Error?) -> Void in

            if error == nil {
                fotosProdutoLojaCollectionViewItem.fotoProdutoLojaImageView.image = NSImage(data: data!)
            }
        })

        if produtoLoja!.fotos[indexPath.item].imagemCapa {
            fotosProdutoLojaCollectionViewItem.fotoCapaImageView.isHidden = false
        }else {
            fotosProdutoLojaCollectionViewItem.fotoCapaImageView.isHidden = true
        }

        return item
    }


override func viewDidLoad() {
        super.viewDidLoad()

        fotosProdutoLojaCollectionView.delegate = self
        fotosProdutoLojaCollectionView.dataSource = self
        fotosProdutoLojaCollectionView.registerForDraggedTypes([NSPasteboard.PasteboardType(kUTTypeData as String)])

        fotosProdutoLojaCollectionView.setDraggingSourceOperationMask(.move, forLocal: true)
    }

这里是pasteboardWriterForItemAt indexPath。我已经尝试了所有注释行。

func collectionView(_ collectionView: NSCollectionView, pasteboardWriterForItemAt indexPath: IndexPath) -> NSPasteboardWriting? {

    let pb = NSPasteboardItem()

    var data: Data?
    do {
        try data = produtoLoja?.fotos[indexPath.item].foto?.getData()
    } catch {

    }
    pb.setData(data!, forType: NSPasteboard.PasteboardType.string)

    return pb

    //return NSPasteboardItem()
    //return data as? NSPasteboardWriting
}

这里是 writeItemsAt indexPaths。

func collectionView(_ collectionView: NSCollectionView, writeItemsAt indexPaths: Set<IndexPath>, to pasteboard: NSPasteboard) -> Bool {

    return true
}

Answer 1

很多方法都错了。这是更正后的代码（只是与集合视图委托和拖放项目的数据源相关的部分）：

ViewDidLoad

var indiceItensMovidosDrag: Set<IndexPath> = []

override func viewDidLoad() {
        super.viewDidLoad()

        fotosProdutoLojaCollectionView.delegate = self
        fotosProdutoLojaCollectionView.dataSource = self
        fotosProdutoLojaCollectionView.registerForDraggedTypes([NSPasteboard.PasteboardType(kUTTypeItem as String)])

        fotosProdutoLojaCollectionView.setDraggingSourceOperationMask(.move, forLocal: true)

        if produtoLoja == nil {
            produtoLoja = ProdutoLoja()
        }
}

现在委托和数据源方法

func numberOfSections(in collectionView: NSCollectionView) -> Int {

        return 1
    }

    func collectionView(_ collectionView: NSCollectionView, numberOfItemsInSection section: Int) -> Int {

        return produtoLoja!.fotos.count
    }

    func collectionView(_ collectionView: NSCollectionView, itemForRepresentedObjectAt indexPath: IndexPath) -> NSCollectionViewItem {

        var item = NSCollectionViewItem()

        item = collectionView.makeItem(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "FotoProdutoLojaCollectionViewItem"), for: indexPath)

        let fotosProdutoLojaCollectionViewItem = item as! FotoProdutoLojaCollectionViewItem

        produtoLoja?.fotos[indexPath.item].foto?.getDataInBackground(block: {
            (data: Data?, error: Error?) -> Void in

            if error == nil {
                fotosProdutoLojaCollectionViewItem.fotoProdutoLojaImageView.image = NSImage(data: data!)
            }
        })

        if produtoLoja!.fotos[indexPath.item].imagemCapa {
            fotosProdutoLojaCollectionViewItem.fotoCapaImageView.isHidden = false
        }else {
            fotosProdutoLojaCollectionViewItem.fotoCapaImageView.isHidden = true
        }

        return item
    }

func collectionView(_ collectionView: NSCollectionView, canDragItemsAt indexPaths: Set<IndexPath>, with event: NSEvent) -> Bool {

        return true
    }

    func collectionView(_ collectionView: NSCollectionView, pasteboardWriterForItemAt indexPath: IndexPath) -> NSPasteboardWriting? {

        let retorno = NSPasteboardItem()

        var data: Data?
        do {
            try data = produtoLoja?.fotos[indexPath.item].foto?.getData()
        } catch {

        }

        retorno.setData(data!, forType: NSPasteboard.PasteboardType(kUTTypeItem as String))

        return retorno
    }

    func collectionView(_ collectionView: NSCollectionView, draggingSession session: NSDraggingSession, willBeginAt screenPoint: NSPoint, forItemsAt indexPaths: Set<IndexPath>) {

        indiceItensMovidosDrag = indexPaths
    }

    func collectionView(_ collectionView: NSCollectionView, draggingSession session: NSDraggingSession, endedAt screenPoint: NSPoint, dragOperation operation: NSDragOperation) {

        indiceItensMovidosDrag = []
    }

    func collectionView(_ collectionView: NSCollectionView, validateDrop draggingInfo: NSDraggingInfo, proposedIndexPath proposedDropIndexPath: AutoreleasingUnsafeMutablePointer<NSIndexPath>, dropOperation proposedDropOperation: UnsafeMutablePointer<NSCollectionView.DropOperation>) -> NSDragOperation {

        if proposedDropOperation.pointee == NSCollectionView.DropOperation.on {
            proposedDropOperation.pointee = NSCollectionView.DropOperation.before
        }

        return NSDragOperation.move
    }

    func collectionView(_ collectionView: NSCollectionView, acceptDrop draggingInfo: NSDraggingInfo, indexPath: IndexPath, dropOperation: NSCollectionView.DropOperation) -> Bool {

        var retorno = true

        if indiceItensMovidosDrag.count == 1 {
            for indice in indiceItensMovidosDrag {
                collectionView.animator().moveItem(at: indice, to: (indexPath.item <= indice.item) ? indexPath : (IndexPath(item: indexPath.item - 1, section: 0)))

            }
        } else {
            mostrarErro(mensagem: "Erro", informativo: "Só é possível mover uma imagem por vez")
            retorno = false
        }

        //fotosProdutoLojaCollectionView.reloadData()

        return retorno
    }

Swift OSX - 通过拖放重新排列 NSCollectionView 无效

Swift OSX - Rearrange NSCollectionView with drag and drop not working

macos

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swift