How do I change background color on cells that are not selected using rx swift?

Question

In order to set a color on a selected cell I do the following:

armSystemTableView.rx.itemSelected.subscribe(onNext: { indexPath in
    let cell = self.armSystemTableView.cellForRow(at: indexPath) as? TechnicianArmSystemTableViewCell
                
    cell?.backgroundColor = .green
                
}).disposed(by: disposeBag)

While this works, it doesn't remove the selection color on all other cells, meaning that every cell I click will turn green. How do I restore all the unselected cells to their original color?

I also tried using override func setSelected(_ selected: Bool, animated: Bool) but that didn't work in conjunction with setting a default selected cell as I think setSelected overrides the default:

armSystemViewModel.content.bind(to: armSystemTableView.rx.items(cellIdentifier: TechnicianArmSystemTableViewCell.identifier, cellType: TechnicianArmSystemTableViewCell.self)) {
    row, data, cell in
        cell.viewModel = data
        if row == cell.viewModel?.parameter.value {
            cell.setSelected(true, animated: false)
        } else {
            cell.setSelected(false, animated: false)
        }
}.disposed(by: disposeBag)

Here I set the default selected cell. But it won't work and I think the reason is that it's overriden by setSelected:

 override func setSelected(_ selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)
    setSelectedColors(selected: selected)
}
    
func setSelectedColors(selected: Bool) {
    if selected {
        contentView.backgroundColor = .green
    } else {
        contentView.backgroundColor = .red
    }
}

There should be a cell marked greed per default, but there isn't. If I remove setSelected and change to setting the background color it will work with the default selected cell:

...
if row == cell.viewModel?.parameter.value {
    cell.backgroundColor = .green
} else {
    cell.backgroundColor = .red
}

So how do I make this happen? Seems simple enough: one cell should be marked green when you enter the view. When selecting any other cell that cell will instead become green and any other cell will become red.

Answer 1

Here's a more Rx'ish way to do it:

items
    .bind(to: tableView.rx.items) { (tableView, row, element) in
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell")!
        cell.textLabel?.text = "\(element) @ row \(row)"
        cell.rx.setSelected
            .subscribe(onNext: { [contentView = cell.contentView] selected, animated in
                contentView.backgroundColor = selected ? .green : .white
            })
            .disposed(by: cell.disposeBag)
        return cell
    }
    .disposed(by: disposeBag)

You will need to define this to get the above to work:

extension Reactive where Base: UITableViewCell {
    var setSelected: Observable<(selected: Bool, animated: Bool)> {
        base.rx.methodInvoked(#selector(UITableViewCell.setSelected(_:animated:)))
            .map { (selected: $0[0] as! Bool, animated: $0[1] as! Bool) }
    }
}

Answer 2

I found a way. Loop all visible cells and change the color on each, then set the color on a specific cell. Not the prettiest I suppose, but it does work:

armSystemTableView.rx.itemSelected.subscribe(onNext: { indexPath in
    self.armSystemTableView.visibleCells.forEach { $0.backgroundColor = .tableviewBackgroundColor }
                
    let cell = self.armSystemTableView.cellForRow(at: indexPath) as? TechnicianArmSystemTableViewCell
    cell?.backgroundColor = .selectedCellColor
}).disposed(by: disposeBag)