Table view cell accessory not changing when out of view - swift

Question

I have this piece of code:
tableView.deselectRowAtIndexPath(indexPath, animated: true)
if let selected = self.lastSelected {
tableView.cellForRowAtIndexPath(selected)?.accessoryType = .None
}
tableView.cellForRowAtIndexPath(indexPath)?.accessoryType = UITableViewCellAccessoryType.Checkmark
self.lastSelected = indexPath
I allows me to place a checkmark on the cell that I select and removes the previous checkmark. The problem I am having is that if the list is large and the cell is out of view, the checkmark is not removed when a new cell is selected.
I have tried adding tableview.reloaddata() but that did nothing.
Thoughts?

Answer 1

cellForRowAtIndexPath returns nil for non-visible cells.
To get a radio button like effect, you need to do something like this:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = UITableViewCell()
configureCell(cell, atIndexPath: indexPath)
return cell
}
func configureCell(cell: UITableViewCell, atIndexPath indexPath: NSIndexPath) {
if indexPath == selectedIndexPath {
cell.accessoryType = .Checkmark
} else {
cell.accessoryType = .None
}
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
selectedIndexPath = indexPath
// Note indexPathsForVisibleRows may be nil depending on your app's content.
// zip just joins two arrays together, into a single array of tuples.
zip(tableView.indexPathsForVisibleRows!, tableView.visibleCells).forEach({ indexPath, cell in
configureCell(cell, atIndexPath: indexPath)
})
}