在表格視圖中按日期排序的單元格項目

Question

我有以下代碼，通過按住然後將項目移動到不同的位置來重新排列表格視圖中的項目，如附圖所示。

該代碼完美適用於按索引路徑排序的對象。

儘管我的模型已更改，但現在按日期排序。關於如何修改代碼以更改以將日期重新分配給交換單元以便將它們保存在覈心數據中的任何想法。

//MARK : - Cell Re-Ordering 
    struct Drag { 
     static var placeholderView: UIView! 
     static var sourceIndexPath: NSIndexPath! 
     static var sourceDate: NSDate! 
    } 

func handleLongPress(gesture: UILongPressGestureRecognizer) { 

    let point = gesture.locationInView(tableView) 
    let indexPath = tableView.indexPathForRowAtPoint(point) 

    switch gesture.state { 
    case .Began: 
     if let indexPath = indexPath { 
      let cell = tableView.cellForRowAtIndexPath(indexPath)! 
      Drag.sourceIndexPath = indexPath 

      var center = cell.center 
      Drag.placeholderView = placeholderFromView(cell) 
      Drag.placeholderView.center = center 
      Drag.placeholderView.alpha = 0 

      tableView.addSubview(Drag.placeholderView) 

      UIView.animateWithDuration(0.25, animations: { 
       center.y = point.y 
       Drag.placeholderView.center = center 
       Drag.placeholderView.transform = CGAffineTransformMakeScale(1.05, 1.05) 
       Drag.placeholderView.alpha = 0.95 

       cell.alpha = 0 
       }, completion: { (_) in 
        cell.hidden = true 
      }) 

     } 
    case .Changed: 
     guard let indexPath = indexPath else { 
      return 
     } 

     var center = Drag.placeholderView.center 
     center.y = point.y 
     Drag.placeholderView.center = center 

     if indexPath != Drag.sourceIndexPath { 

      /////////////// Swap the Index Path /////////////// 
      swap(&self.weekDayModel.exerciseItems[indexPath.row], &self.weekDayModel.exerciseItems[Drag.sourceIndexPath.row]) //Previous Model Swapping 
      tableView.moveRowAtIndexPath(Drag.sourceIndexPath, toIndexPath: indexPath) 
      Drag.sourceIndexPath = indexPath 
     } 
    default: 
     if let cell = tableView.cellForRowAtIndexPath(Drag.sourceIndexPath) { 
      cell.hidden = false 
      cell.alpha = 0 

      UIView.animateWithDuration(0.25, animations: { 
       Drag.placeholderView.center = cell.center 
       Drag.placeholderView.transform = CGAffineTransformIdentity 
       Drag.placeholderView.alpha = 0 
       cell.alpha = 1 
       }, completion: { (_) in 
        Drag.sourceIndexPath = nil 
        Drag.placeholderView.removeFromSuperview() 
        Drag.placeholderView = nil 
      }) 
     } 
    } 
} 

func placeholderFromView(view: UIView) -> UIView { 

    UIGraphicsBeginImageContextWithOptions(view.bounds.size, false, 0.0) 
    view.layer.renderInContext(UIGraphicsGetCurrentContext()!) 
    let image = UIGraphicsGetImageFromCurrentImageContext() as UIImage 
    UIGraphicsEndImageContext() 

    let snapshotView : UIView = UIImageView(image: image) 
    snapshotView.layer.masksToBounds = false 
    snapshotView.layer.cornerRadius = 0.0 
    snapshotView.layer.shadowOffset = CGSizeMake(-5.0, 0.0) 
    snapshotView.layer.shadowRadius = 5.0 
    snapshotView.layer.shadowOpacity = 0.4 
    return snapshotView 
} 

我的核心數據模型：

import CoreData 
@objc(graduationModel) 
class graduationModel: NSManagedObject { 

    // Insert code here to add functionality to your managed object subclass 

} 
extension graduationModel { 

    @NSManaged var Name: String? 
    @NSManaged var graduation: String? 

    @NSManaged var date: NSDate? 

} 

任何想法是極大的讚賞。

Answer 1

排序核心數據對象

• 什麼出來的核心數據是NSSet，即無序對象。假設我爲了速度而折衷。您只能按照您提供給您的屬性進行排序。

• 更改模型並反映UI中的新順序，而不是更改UI並希望傳播到Core Data。使用NSFetchResultController將處理所有UI刷新：您需要注意的是您的Core Data完整性。

型號

只能使用排序關聯到你的對象的屬性。考慮使用遞增的唯一標識符，創建NSDate，修改NSDate，所有這些都將幫助您稍後對您的內容進行排序。

用戶界面

極大地撬動NSFetchedResultsController降低你的工作。

---

同時使用適當的模型和NSFetchedResultsControllerhere排序的一個例子。