完了ブロックの空の配列を渡す

Question

私はいくつかの汎用コードを使用して複数のコレクションビューの配列を作成し、コレクションビューがあるviewcontrollerにデータの配列を渡そうとしているクラスを持っています。

私が今問題にしたのは、クエリが完了する前に結果が完了ハンドラに渡されているということです。

私はここで間違っていますか？理論的には私はうまくいくはずです。

import UIKit 
import Parse 

class BuildArray: UICollectionViewController { 
    class func buildArrayFromQuery(queryForCollection: String, sender: UIViewController, completeBlock: (_ result: Any) -> Void) { 
     struct collectionStruct { 
      var name : String 
      var description : String 
      var title : String 
      var image : PFFile 
      var id: String 
     } 

     var collectionArray = [collectionStruct]() 

     //var queryFromSource = 
     var fromClass = "" 
     var fromName = "" 
     var fromDescription = "" 
     var fromTitle = "" 
     var fromImage = "" 

     //------------------------------------------------------------- set the class to query based off the collection 

     if queryForCollection == "Pack" { 
      fromClass = "Pack" 
      fromName = "packName" 
      fromDescription = "packDescription" 
      fromTitle = "packTitle" 
      fromImage = "packImage" 
     } else if queryForCollection == "Part" { 
      fromClass = "Part" 
      fromName = "partName" 
      fromDescription = "partDescription" 
      fromTitle = "partTitle" 
      fromImage = "partImage" 
     } 

     //------------------------------------------------------------- check reachability and set LDS if required 

     var query = PFQuery(className: fromClass) 
     query.order(byAscending: fromName) 

     CheckReachability.setupReachability(hostName: nil) { (block) in 
      if (block) { 
       //var connected = true 
      } else { 
       //var connected = false 
       query.fromLocalDatastore() 
      } 
     } 

     //------------------------------------------------------------- find the objects 

     query.findObjectsInBackground(block: { (objects, error) in 
      if error != nil { 
       print(error!) 
      } else if let packs = objects { 
       //------------------------------------------------------------- if we have objects and were reachable unpin everthing so it can be updated 
       CheckReachability.setupReachability(hostName: nil) { (block) in 
        if (block) { 
         PFObject.unpinAllObjectsInBackground(withName: "packDataLDS") 
        } 
       } 

       //------------------------------------------------------------- if there are objects loop through 

       for object in packs { 
        print(fromName) 
        print(object) 

        let arrayName = object.object(forKey: fromName) as! String 
        let arrayDescription = object.object(forKey: fromDescription) as! String 
        let arrayTitle = object.object(forKey: fromTitle) as! String 
        let arrayImage = object.object(forKey: fromImage) as! PFFile 
        let arrayID = object.objectId as String! 

        collectionArray.append(collectionStruct(name: arrayName, description: arrayDescription, title: arrayTitle, image: arrayImage, id: arrayID!)) 
       } 

       //    DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { 
       //     sender.collectionView?.reloadData() 
       //     sender.collectionView?.layoutIfNeeded() 
       //     sender.collectionView?.setScaledDesginParam(scaledPattern: .verticalCenter, maxScale: 1.0, minScale: 0.8, maxAlpha: 1.0, minAlpha: 0.5) 
       //     sender.collectionView?.scaledVisibleCells() 
       // 
       ////     if sender.collectionView?.dataSource?.collectionView(sender.collectionView!, cellForItemAt: IndexPath(item: 0, section: 0)) != nil { 
       ////      //self.collectionView?.scrollToItem(at: IndexPath(item: self.packIndexLDS, section: 0), at: .centeredVertically, animated: true) 
       ////      let rect = sender.collectionView.layoutAttributesForItem(at: IndexPath(item: sender.packIndexLDS, section: 0))?.frame 
       ////      self.collectionView.scrollRectToVisible(rect!, animated: false) 
       ////     } 
       //    } 
      } 

      //------------------------------------------------------------- if we are reachable pin everthing 

      CheckReachability.setupReachability(hostName: nil) { (block) in 
       if (block) { 
        PFObject.pinAll(inBackground: objects, withName: "packDataLDS") 
       } 
      } 

     }) 

     completeBlock(result: collectionArray) 
    } 
} 

Answer 1

completeBlock(result: collectionArray)は、クエリの完了ブロックの外に呼び出しています。クエリーの完了ブロック内ではなく、クエリーの完了ブロック内に移動します。

あなたが持っている：

query.findObjectsInBackground(block: { (objects, error) in 
     // lots of stuff removed for clarity 
    }) 

    completeBlock(result: collectionArray) 

が、それはする必要があります：

query.findObjectsInBackground(block: { (objects, error) in 
     // lots of stuff removed for clarity 

     completeBlock(result: collectionArray) 
    })