Reload a table view's data without clearing its selection state

Question

I have a table view with selectable rows. When I reload the table view some new rows might be added (or removed) and some labels in the table view's cells might change. That's what I want to achieve by calling [tableView reloadData].

Unfortunately that method also clears the table view's whole state - including the selection. But I need to keep the selection.

So how can I reload all the data in a table view while still keeping the selected rows selected?

Answer 1

You can store the index path of the selected row with:

rowToSelect = [yourTableView indexPathForSelectedRow];

Before reload the data. And after reload use:

[yourTableView selectRowAtIndexPath:rowToSelect animated:YES scrollPosition:UITableViewScrollPositionNone];

Answer 2

JeroVallis solution works for single selection table views. Based on his idea this is how I made it work with multiple selection:

NSArray *selectedIndexPaths = [self.tableView indexPathsForSelectedRows];
[tableView reloadData];
for (int i = 0; i < [selectedIndexPaths count]; i++) {
    [tableView selectRowAtIndexPath:selectedIndexPaths[i] animated:NO scrollPosition:UITableViewScrollPositionNone];
}

Answer 3

The most efficient way is to keep the selected state in the data model

• Add a boolean property isSelected in the struct or class which represents the data source.
• In cellForRowAt set the selected state of the cell according to the property.
• In didSelectRow toggle isSelected in the data source item and reload only the particular row at the given index path.

Answer 4

An alternative that has some advantages is to only reload the rows that have not been selected. Swift code below.

        if var visibleRows = tableView.indexPathsForVisibleRows,
            let indexPathIndex = visibleRows.index(of: indexPath) {
            visibleRows.remove(at: indexPathIndex)
            tableView.reloadRows(at: visibleRows, with: .none)
        }

Answer 5

Swift 4.2 Tested

The correct way to update selected rows after reload table view is:

// Saves selected rows
let selectredRows = tableView.indexPathsForSelectedRows

tableView.reloadData()

// Select row after table view finished reload data on the main thread
DispatchQueue.main.async {
    selectredRows?.forEach({ (selectedRow) in
        tableView.selectRow(at: selectedRow, animated: false, scrollPosition: .none)
    })
}