iOS，带有观察者的自定义表格视图单元，如何分离观察者

Question

So we have this Table View Custom Cell with it's own class. In the class we are playing with putting Key Value Pair Observers. Yes, we have reason for this...

Anyway, at certain times are are getting...

An instance 0x7680410 of class CustomCellBase was deallocated while key value observers
were still registered with it. Observation info was leaked, and may even become mistakenly
attached to some other object.

This is of course due to the cells being "reused".

What would be the best way to clear these? Is there a way? Is it the case that we can not use Observers in Custom Table Cells?

Answer 1

You need to stop observing the cell when it's removed from view.

- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
{
    [[NSNotificationCenter defaultCenter] removeObserver:cell];
}

Otherwise NSNotificationCenter will try to fire the selector on removed cell causing the error. Of course you will need to re-register the cell when it appears.