如何更改 UICollectionView 中所选项目的单元格背景颜色，并将其他单元格颜色更改为默认值 swift

Question

I am new in swift and I am trying to change cell background colour of UICollectionView but its not working my code is like this in cellForItemAt

if(cell.isSelected){
    cell.backgroundColor = UIColor.green
    }else{
       cell.backgroundColor = UIColor.clear
 }

Is there is any way to change only selected cell colour to green and other cell to clear Thanks in Advance!

Answer 1

Create a variable inside the vc

var currentSelected:Int?

then inside cellForItemAt

cell.backgroundColor = currentSelected == indexPath.row ? UIColor.green : UIColor.clear

finally didSelectItemAt

currentSelected = indexPath.row
collectionView.reloadData()

Don't depend on isSelected as cells are dequeued and when you scroll you'll get unexpected results

Answer 2

According to Apple's explanation about cell's backgroungView and selected backgroundView Here you should change those parameters at the cell class itself and the UICollectionView will know to manage it automatically when the cell is highlighted or selected:

override func awakeFromNib() {
  super.awakeFromNib()

  let redView = UIView(frame: bounds)
  redView.backgroundColor = #colorLiteral(red: 1, green: 0, blue: 0, alpha: 1)
  self.backgroundView = redView

  let blueView = UIView(frame: bounds)
  blueView.backgroundColor = #colorLiteral(red: 0, green: 0, blue: 1, alpha: 1)
  self.selectedBackgroundView = blueView
}