NSOutlineView拖线卡住+蓝色边框

Question

我想要蓝色拖动条的正确行为，并且拖动时没有蓝色矩形。

你知道我的错误在哪里吗？

（如您所见，蓝色条卡在顶部，如本主题所示： Little circle-line bar stuck at top of NSOutlineView when rearranging using drag and drop)

import Cocoa

class ViewController: NSViewController, NSOutlineViewDataSource, NSOutlineViewDelegate, NSPasteboardItemDataProvider {

    @IBOutlet weak var outlineView: NSOutlineView!

    let REORDER_PASTEBOARD_TYPE = "com.test.calques.item"

    override func viewDidLoad() {
        super.viewDidLoad()

        //Register for the dropped object types we can accept.
        outlineView.register(forDraggedTypes: [REORDER_PASTEBOARD_TYPE])

        //Disable dragging items from our view to other applications.
        outlineView.setDraggingSourceOperationMask(NSDragOperation(), forLocal: false)

        //Enable dragging items within and into our view.
        outlineView.setDraggingSourceOperationMask(NSDragOperation.every, forLocal: true)

        outlineView.delegate = self;
        outlineView.dataSource = self;
    }

    override var representedObject: Any? {
        didSet {
            // Update the view, if already loaded.
        }
    }

    var items: [(String, NSColor)] = [
        ("Item 1",  NSColor.black),
        ("Item 2",  NSColor.red),
        ("Item 3",  NSColor.red),
        ("Item 4",  NSColor.red),
        ("Item 5",  NSColor.red),
        ("Item 6",  NSColor.red)];

    //NSOutlineViewDataSource
    func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
        return items.count;
    }

    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        return false
    }

    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        return items[index];
    }

    func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
        let image: NSImage = NSImage(size: NSSize(width: 17, height: 17));
        let calquesItem: (String, NSColor) = item as! (String, NSColor);
        let path = NSBezierPath(ovalIn: CGRect(x: 2, y: 2, width: 17 - 4, height: 17 - 4));

        image.lockFocus();
        calquesItem.1.setFill();
        path.fill();
        image.unlockFocus();

        let cell = outlineView.make(withIdentifier: "DataCell", owner: nil) as! NSTableCellView;
        cell.textField!.stringValue = calquesItem.0;
        cell.imageView!.image = image;

        return cell;
    }

    //Drag - NSOutlineViewDataSource
    var fromIndex: Int? = nil;

    func outlineView(_ outlineView: NSOutlineView, pasteboardWriterForItem item: Any) -> NSPasteboardWriting? {
        let pastBoardItem: NSPasteboardItem = NSPasteboardItem();

        pastBoardItem.setDataProvider(self, forTypes: [REORDER_PASTEBOARD_TYPE]);

        return pastBoardItem;
    }

    func outlineView(_ outlineView: NSOutlineView, draggingSession session: NSDraggingSession, willBeginAt screenPoint: NSPoint, forItems draggedItems: [Any]) {

        Swift.print("willBeginAt")

        let item = draggedItems[0] as! (String, NSColor);

        fromIndex = items.index(where: { (_item: (String, NSColor)) -> Bool in
            return _item.0 == item.0
        });

        session.draggingPasteboard.setData(Data(), forType: REORDER_PASTEBOARD_TYPE)
    }

    func outlineView(_ outlineView: NSOutlineView, acceptDrop info: NSDraggingInfo, item: Any?, childIndex index: Int) -> Bool {
        Swift.print("acceptDrop")

        if(fromIndex! != index && index != -1) {
            let toIndex: Int = fromIndex! < index ? index - 1 : index;

            outlineView.moveItem(at: fromIndex!, inParent: nil, to: toIndex, inParent: nil);

            items.insert(items.remove(at: fromIndex!), at: toIndex);

            return true;
        }

        return false;
    }

    func outlineView(_ outlineView: NSOutlineView, validateDrop info: NSDraggingInfo, proposedItem item: Any?, proposedChildIndex index: Int) -> NSDragOperation {
        if(item == nil) {
            return NSDragOperation.generic;
        }

        return [];
    }

    func outlineView(_ outlineView: NSOutlineView, draggingSession session: NSDraggingSession, endedAt screenPoint: NSPoint, operation: NSDragOperation) {
        Swift.print("Drag session ended")
        fromIndex = nil;
    }

    //NSPasteboardItemDataProvider
    func pasteboard(_ pasteboard: NSPasteboard?, item: NSPasteboardItem, provideDataForType type: String)
    {
        item.setString("Outline Pasteboard Item", forType: type)
    }

}

Answer 1

来自 https://developer.apple.com/reference/appkit/nsoutlineview :

Each item in the outline view must be unique. In order for the collapsed state to remain consistent between reloads the item's pointer must remain the same and the item must maintain isEqual(_:) sameness.

我使用的是元组（字符串、NSColor）。并且元组不符合 hashable 协议！

从 Tuples 项目切换到 MyClass 项目后，一切正常！（蓝色拖动条的正确行为，拖动时没有蓝色矩形）

class MyClass {
    var name: String!
    var color: NSColor!

    init(_ _name: String, _ _color: NSColor) {
        name = _name
        color = _color
    }
}

NSOutlineView拖线卡住+蓝色边框

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