UITableView: swiping RowAction cancels the selected rows

Question

I can see this behavior in both deprecated UITableViewRowAction class and UISwipeActionsConfiguration class:

If you have allowsMultipleSelection property set to true and, let's say, you have 3 rows selected:

When you start swiping any row in the table for a RowAction the previously selected rows -- all 3 of them -- become unhighlighted, and the property indexPathsForSelectedRows drops to nil.

• Does this behavior make sense?
• Is there any 'deselecting' callback (because I'm displaying the number of selected rows)
• What are possible workarounds to persist the array of selected rows?

Interlanguage

Answer 1

UITableView enters editing mode when you swipe a row in the table. This is your

'deselecting' callback

You can backup your selected rows on entering the mode and restore on exiting:

class ViewController: UITableViewController {

    var indexPathsForSelectedRows: [IndexPath]?

    override func setEditing(_ editing: Bool, animated: Bool) {
        if editing {
            indexPathsForSelectedRows = tableView.indexPathsForSelectedRows
        } else {
            indexPathsForSelectedRows?.forEach { tableView.selectRow(at: $0, animated: false, scrollPosition: .none) }
        }
        super.setEditing(editing, animated: animated)
    }
}

Also note that if you re-arrange/delete/insert rows during editing, you'll need to update your stored indexPathsForSelectedRows accordingly so you restore correct index paths.

Trinitrocresol

I'm pretty sure you must add super.setEditing(editing, animated) to the overridden function though – Interlanguage

Also unfortunately neither override func setEditing(_:, :) nor override var isEditing { didSet { } } is called when the UITableView is entering/leaving the editing mode :( so this solution doesn't seem to be correct – Interlanguage

Did you set your UITableView delegates? – Trinitrocresol

The method setEditing() is not a part of a delegate protocol, why are you asking? – Interlanguage

If you subclass UITableViewController then overriding setEditing (by the way calling super.setEditting() clears tableView.indexPathsForSelectedRows) should work. Otherwise you can implement willBeginEditingRowAt and didEndEditingRowAt appropriately in your UITableViewDelegate. – Trinitrocresol

So as a belated update, since I'm still bumping into this task: neither isEditing nor setEditing can be used as 'callbacks' because they are not called when the editing mode changes (I subclassed UITableView and tried to used the didSet{} hook). But your suggestion with the delegate's methods willBeginEditing... didEndEditing... is working ok. – Interlanguage