图像中带有复选框的 UICollectionView 单元格答案

【问题标题】：UICollectionView Cell with tick box in the image图像中带有复选框的 UICollectionView 单元格
【发布时间】：2015-07-30 00:22:58
【问题描述】：

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell
    {

        var cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! CollectionViewCell
        println(indexPath)
        cell.imageView.contentMode = .ScaleAspectFill
        cell.backgroundColor = UIColor.whiteColor()
        cell.layer.borderColor = UIColor.blackColor().CGColor
        cell.layer.borderWidth = 0.1
        cell.frame.size.width = self.screenWidth / 3
        cell.frame.size.height = self.screenWidth / 3


        let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
        let documentsDirectory = paths[0] as! String
        cell.imageView.image = UIImage(contentsOfFile: self.getMediaFilePath(self.mediaModels[indexPath.row].pathToMedia))
        cell.imageTicked.hidden = true

        return cell

    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAtIndex section: Int) -> CGFloat {
        return 1
    }

    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath){

        var cell : UICollectionViewCell = collectionView.cellForItemAtIndexPath(indexPath)!
        //cell.backgroundColor = UIColor.magentaColor()
        self.mediaModels[indexPath.row].isSelected  = true
        cell.selected = true
    }
    func collectionView(collectionView: UICollectionView, didDeselectItemAtIndexPath indexPath: NSIndexPath){

        var cell : UICollectionViewCell = collectionView.cellForItemAtIndexPath(indexPath)!
        //cell.backgroundColor = UIColor.whiteColor()
        self.mediaModels[indexPath.row].isSelected  = false
        cell.selected = false
    }

我可以在返回单元格的函数中隐藏 imageTicked，但我无法将其添加到 didSelectItemAtIndexPath 和 didDeselectItemAtIndexPath 中。我想在选择项目时显示复选框，并在取消选择项目时隐藏复选框。

只是想知道如何在didDeselectItemAtIndexPath 内设置cell.imageTicked.hidden = true 和在didSelectItemAtIndexPath 内设置cell.imageTicked.hidden = false。

非常感谢您的帮助

【问题讨论】：

标签： ios iphone swift ios8

【解决方案1】：

您只需要创建一个 selectedIndexPath 变量。在 didSelectItemAtIndexPath 中设置它并在 didDeselectItemAtIndexPath 中删除。记得调用 reloadData() 来重新加载集合视图。

var selectedIndexPath: NSIndexPath?;
...         
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath: NSIndexPath){
   ...
   if selectedIndexPath != nil {
      cell.imageTicked.hidden = selectedIndexPath.row == indexPath.row
   }
   else {
      cell.imageTicked.hidden = true
   }
}

func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath){
   ...
   self.selectedIndexPath = indexPath
   collectionView.reloadData()
}

func collectionView(collectionView: UICollectionView, didDeselectItemAtIndexPath indexPath: NSIndexPath){
  ...
  self.selectedIndexPath = nil
  collectionView.reloadData()
}

【讨论】：