title: Cells insight UICollectionView do not load until there are visible?
body: <p>I have a <code>UITableView</code> with <code>UICollectionView</code> insight every table view cell. I use the <code>UICollectionView</code> view as a gallery (collection view with paging). My logic is like this:
  Insight the method </p>
  
  <pre><code>func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -&gt; UITableViewCell {
  
      // This is a dictionary with an index (for the table view row),
      // and an array with the url's of the images
      self.allImagesSlideshow[indexPath.row] = allImages
  
      // Calling reloadData so all the collection view cells insight
      // this table view cell start downloading there images               
      myCell.collectionView.reloadData() 
  }
  </code></pre>
  
  <p>I call <code>collectionView.reloadData()</code> and in the</p>
  
  <pre><code>func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -&gt; UICollectionViewCell {
      // This method is called from the cellForRowAtIndexPath of the Table
      // view but only once for the visible cell, not for the all cells,
      // so I cannot start downloading the images
  
  
    let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! PhotoCollectionCell
  
      if self.allImagesSlideshow[collectionView.tag] != nil {
  
          var arr:[String]? = self.allImagesSlideshow[collectionView.tag]!
  
          if let arr = arr {
  
              if indexPath.item &lt; arr.count {
  
                  var imageName:String? = arr[indexPath.item]
  
                  if let imageName = imageName {
  
                      var escapedAddress:String? = imageName.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
  
                      if let escapedAddress = escapedAddress {
  
                          var url:NSURL? = NSURL(string: escapedAddress)
  
                          if let url = url {
  
                              cell.imageOutlet.contentMode = UIViewContentMode.ScaleAspectFill
  
                              cell.imageOutlet.hnk_setImageFromURL(url, placeholder: UIImage(named: "placeholderImage.png"), format: nil, failure: nil, success: nil)
  
                          }
                      }
                  }
              }
          }
      }
  
      return cell
  }
  
  func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -&gt; Int {
  
          if self.allImagesSlideshow[collectionView.tag] != nil {
  
              var arr:[String]? = self.allImagesSlideshow[collectionView.tag]!
  
              if let arr = arr {
  
                   println("collection row: \(collectionView.tag), items:\(arr.count)")
  
                  return arr.count
              }
          }
  
          return 0
      }
  </code></pre>
  
  <p>I set the right image for the cell. The problem is that the above method is called only for the first collection view cell. So when the user swipe to the next collection view cell the above method is called again but and there is a delay while the image is downloaded. I would like all the collection view cells to be loaded insight every visible table view cell, not only the first one. </p>
  
  <p>Using the image I have posted, "Collection View Cell (number 0)" is loaded every time but "Collection View Cell (number 1)" is loaded only when the user swipe to it. How I can force calling the above method for every cell of the collection view, not only for the visible one? I would like to start the downloading process before swiping of the user.</p>
  
  <p>Thank you!</p>
  
  <p><img src="https://i.stack.imgur.com/BtJhC.png" alt="enter image description here"></p>