ios - 如何将特定图像设置到特定数组位置？

Question

我正在使用 UICollectionView 进行水平滚动，在 array 中有六个图像。我想要的是当索引路径 x(1) 上的项目被单击时，图像数组将设置在除位置 1 之外的剩余项目 (0,2,3,4,5) 上。我们可以在特定位置设置特定图像吗数组的位置如果是那么如何？

在Android的情况下，就像

if (selectedPosition < 0) {
  viewHolder.imageView.setImageResource(coloredSmiley[position]);
} else {
  viewHolder.imageView.setImageResource(selectedPosition == position ? coloredSmiley[position] : greySmiley[position]);
}


import UIKit

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

    var selectedImageButton = -1
    var imagearray = ["AngrysmIcon1", "UpsetsmIcon2", "ConfusedsmIcon3", "MehsmIcon4", "CurioussmIcon5" , "HappysmIcon6"]
    var bwimagearray = ["AngrysmIcon1Inactive", "UpsetsmIcon2Inactive", "ConfusedsmIcon3Inactive", "MehsmIcon4Inactive", "CurioussmIcon5Inactive", "HappysmIcon6Inactive"]

    var positiontag = ["0", "1", "2", "3", "4", "5"]

    override func viewDidLoad() {
        super.viewDidLoad()

        }

  func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

            return self.positiontag.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! UIcollectionViewCellCollectionViewCell
            cell.imagev.image = UIImage(named: imagearray[indexPath.row])
            return cell

    }
    func numberOfSections(in collectionView: UICollectionView) -> Int {
            return 1
    }

    internal func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)   {

        selectedImageButton = indexPath.row

        let cell = collectionView.cellForItem(at: indexPath) as! UIcollectionViewCellCollectionViewCell
        if selectedImageButton < 0 {

            //cell.imagev.image = bwimagearray[indexPath.row]

        } else {
            cell.imagev.image = UIImage(named: imagearray[indexPath.row])

        } 
    }
}

selectedposition 是全局的，值为 -1

Answer 1

从 Android 片段，我相信你需要改变 cellForRowAt 如下，

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
      let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! UIcollectionViewCellCollectionViewCell
      let imageName: String
      if selectedImageButton < 0 {
          imageName = imagearray[indexPath.row]
      } else {
          imageName = selectedImageButton == indexPath.row ? imagearray[indexPath.row] : bwimagearray[indexPath.row]
      }
      cell.imagev.image = UIImage(named: imageName)
      return cell

}

然后在didSelectItemAt中设置selectedImageButton并重新加载collectionView,

internal func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)   {
        selectedImageButton = indexPath.row
        collectionView.reloadData()
}

注意:ReloadData 可能不被推荐，您应该寻找一些更具 react 性的方式来通知单元格更新图像。