Stop a collection view deselecting an item

Question

I have a UICollectionView that is a calendar. It's a single scrollable row. Some of the dates are unselectable as there is no data for that date. Others ARE selectable as there IS data for that date.

When a date is selected the calendar underlines the selected date and scrolls it to the center of the UICollectionView.

When a date is tapped that doesn't have a date I have this function...

override func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {
    return //is there data for the date at this indexPath?
}

This stops those cells being selected... however, it still deselects the previously selected cell.

There is a shouldDeselect function but I can't use this as I don't know the index of the tapped cell. So I can't determine whether the item should be deselected.

Is there a better way of doing this?

Answer 1

It simple works for me when I reload the collectionview:

func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {
    // return true whithout reloadData when necessarily
    collectionView.reloadData()
    return false
}

Answer 2

I recently had the same issue and I ended up with the following approach:

Whenever user selects a cell, remember the position in a member variable:

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

After that call myCollectionView.reloadData()

In the cellForRowAtIndexPath: apply appropriate configuration for the cell:

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: MyCell.identifier, for: indexPath) as! MyCell
    if indexPath.row == myMemberVariable && canSelectCellAt(indexPath: indexPath) {
        cell.backgroundColor = .green
    } else {
        cell.backgroundColor = .gray
    }

    return cell
}

Where canSelectCellAt(indexPath: indexPath) is a function, which returns true for selectable cells and false for non-selectable cells,