Перетаскивание представлений в NSStackView для изменения последовательности

Question

Можно ли изменить порядок просмотров в NSStackView, перетащив подзоны, как мы это делаем в NSTableView?

Answer 1

Нет встроенной поддержки для переопределения подпрограмм NSStackView.

Answer 2

Вот реализация подкласса NSStackView, содержимое которого может быть заказана с помощью перетаскивания:

// 
// DraggingStackView.swift 
// Analysis 
// 
// Created by Mark Onyschuk on 2017-02-02. 
// Copyright © 2017 Mark Onyschuk. All rights reserved. 
// 
import Cocoa 

class DraggingStackView: NSStackView { 

    var isEnabled = true 

    // MARK: - 
    // MARK: Update Function 
    var update: (NSStackView, Array<NSView>)->Void = { stack, views in 
     stack.views.forEach { 
      stack.removeView($0) 
     } 

     views.forEach { 
      stack.addView($0, in: .leading) 

      switch stack.orientation { 
      case .horizontal: 
       $0.topAnchor.constraint(equalTo: stack.topAnchor).isActive = true 
       $0.bottomAnchor.constraint(equalTo: stack.bottomAnchor).isActive = true 

      case .vertical: 
       $0.leadingAnchor.constraint(equalTo: stack.leadingAnchor).isActive = true 
       $0.trailingAnchor.constraint(equalTo: stack.trailingAnchor).isActive = true 
      } 
     } 
    } 


    // MARK: - 
    // MARK: Event Handling 
    override func mouseDragged(with event: NSEvent) { 
     if isEnabled { 
      let location = convert(event.locationInWindow, from: nil) 
      if let dragged = views.first(where: { $0.hitTest(location) != nil }) { 
       reorder(view: dragged, event: event) 
      } 
     } else { 
      super.mouseDragged(with: event) 
     } 

    } 

    private func reorder(view: NSView, event: NSEvent) { 
     guard let layer = self.layer else { return } 
     guard let cached = try? self.cacheViews() else { return } 

     let container = CALayer() 
     container.frame = layer.bounds 
     container.zPosition = 1 
     container.backgroundColor = NSColor.underPageBackgroundColor.cgColor 

     cached 
      .filter { $0.view !== view } 
      .forEach { container.addSublayer($0) } 

     layer.addSublayer(container) 
     defer { container.removeFromSuperlayer() } 

     let dragged = cached.first(where: { $0.view === view })! 

     dragged.zPosition = 2 
     layer.addSublayer(dragged) 
     defer { dragged.removeFromSuperlayer() } 

     let d0 = view.frame.origin 
     let p0 = convert(event.locationInWindow, from: nil) 

     window!.trackEvents(matching: [.leftMouseDragged, .leftMouseUp], timeout: 1e6, mode: .eventTrackingRunLoopMode) { event, stop in 
      if event.type == .leftMouseDragged { 
       let p1 = self.convert(event.locationInWindow, from: nil) 

       let dx = (self.orientation == .horizontal) ? p1.x - p0.x : 0 
       let dy = (self.orientation == .vertical) ? p1.y - p0.y : 0 

       CATransaction.begin() 
       CATransaction.setDisableActions(true) 
       dragged.frame.origin.x = d0.x + dx 
       dragged.frame.origin.y = d0.y + dy 
       CATransaction.commit() 

       let reordered = self.views.map { 
        (view: $0, 
        position: $0 !== view 
         ? NSPoint(x: $0.frame.midX, y: $0.frame.midY) 
         : NSPoint(x: dragged.frame.midX, y: dragged.frame.midY)) 
        } 
        .sorted { 
         switch self.orientation { 
         case .vertical: return $0.position.y < $1.position.y 
         case .horizontal: return $0.position.x < $1.position.x 
         } 
        } 
        .map { $0.view } 

       let nextIndex = reordered.index(of: view)! 
       let prevIndex = self.views.index(of: view)! 

       if nextIndex != prevIndex { 
        self.update(self, reordered) 
        self.layoutSubtreeIfNeeded() 

        CATransaction.begin() 
        CATransaction.setAnimationDuration(0.15) 
        CATransaction.setAnimationTimingFunction(CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)) 

        for layer in cached { 
         layer.position = NSPoint(x: layer.view.frame.midX, y: layer.view.frame.midY) 
        } 

        CATransaction.commit() 
       } 

      } else { 
       view.mouseUp(with: event)      
       stop.pointee = true 
      } 
     } 
    } 

    // MARK: - 
    // MARK: View Caching 
    private class CachedViewLayer: CALayer { 
     let view: NSView! 

     enum CacheError: Error { 
      case bitmapCreationFailed 
     } 

     override init(layer: Any) { 
      self.view = (layer as! CachedViewLayer).view 
      super.init(layer: layer) 
     } 

     init(view: NSView) throws { 
      self.view = view 

      super.init() 

      guard let bitmap = view.bitmapImageRepForCachingDisplay(in: view.bounds) else { throw CacheError.bitmapCreationFailed } 
      view.cacheDisplay(in: view.bounds, to: bitmap) 

      frame = view.frame 
      contents = bitmap.cgImage 
     } 

     required init?(coder aDecoder: NSCoder) { 
      fatalError("init(coder:) has not been implemented") 
     } 
    } 

    private func cacheViews() throws -> [CachedViewLayer] { 
     return try views.map { try cacheView(view: $0) } 
    } 

    private func cacheView(view: NSView) throws -> CachedViewLayer { 
     return try CachedViewLayer(view: view) 
    } 
} 

код требует вашего стека, чтобы быть слой поддерживается, и использует подслоя для моделирования и анимации свои взгляды контента во время обработки перетаскивания. Перетаскивание определяется переопределением mouseDragged (с :), поэтому не будет инициировано, если содержимое стека потребляет это событие.