What is the meaning of the “no index path for table cell being reused” message in iOS 6/7?

Question

Since starting to compile my app with iOS 6 (and since also iOS 7) I\'ve started seeing this message. I know that the way that UITableViews go about managing cells is diffe

Answer 1

This is obviously an old question, but hopefully this can help anyone who still gets this issue in iOS8+ because this is still the top question that comes up for this particular error message.

I was using PINRemoteImage to async download an image to a UIImageView that was inside a custom UITableViewCell.

In order to resize the row properly (dynamic height cells using auto-layout) once the image had loaded, I called:

self.tableView beginUpdates;
self.tableView endUpdates;

I was then getting the "no index path for table cell being reused" message and the app was crashing. I had thought the PINRemoteImageManagerResult block was on the main thread, however it turns out that it wasn't - therefore ensuring that the begin/end updates was called on the main thread fixed the issue.

dispatch_async(dispatch_get_main_queue(), ^(void){
                            [self.tableView beginUpdates];
                            [self.tableView endUpdates];
});

Answer 2

As an addition to my previous post (in which I mentioned that this was apparently a bug with UIKit), I was able to find a workaround for my particular case (in which the message was related to some strange visualisation glitches on the table).

Apparently my custom cell's overridden -(void)setEditing:animated: was taking too long to return.

My previous code was:

- (void)setEditing:(BOOL)editing animated:(BOOL)animated
{   
    [super setEditing:editing animated:animated];
    [self someAdditionalCode];
}

I was able to fix it by changing it to:

- (void)setEditing:(BOOL)editing animated:(BOOL)animated
{   
    [super setEditing:editing animated:animated];

    // DRM: we want to perform the actions from this block in the main thread, but
    // asynchronously to avoid excessive delays which were causing issues.
    //
    dispatch_async(dispatch_get_main_queue(), ^void()
    {
        [self someAdditionalCode];
    });
}

Answer 3

Maybe this helps someone: i once had this error while refreshing a single table view cell. I meant to do something like

NSIndexPath *reloadRow = [NSIndexPath indexPathForRow:1 inSection:2];
[self._mainTableView reloadRowsAtIndexPaths:@[reloadWebViewRow]
                           withRowAnimation:UITableViewRowAnimationFade];

But accidentally, i typed

NSIndexPath *reloadRow = [NSIndexPath indexPathForItem:1 inSection:2];

Notice the difference of the two indexpaths: one is created with indexPathForItem (wrong), the other with indexPathForRow (correct). This all resulted in very strange behaviour of the tableView and the error message in the headline.

Answer 4

Doing my endupdates after resignfirstresponder solved my problem (Have a UITextFIeld in my custom cell)

-(void)textfieldEditDone
{
....

    [textField resignFirstResponder];
    [self.tableView endUpdates];

Answer 5

I'd return the contentView of the UITableViewCell instead of creating a wrapper.. having constraint-jabble fixed in storybord in mind

return cell.contentView;

Answer 6

It seems like my issue was triggered when I was trying to update the UI within a portion of the code that was a callback from a web call. I resolved by forcing UI updates to happen on the main thread. I used code like this.

void runOnMainQueueWithoutDeadlocking(void (^block)(void)){
    if ([NSThread isMainThread])
    {
        block();
    }
    else
    {
        dispatch_sync(dispatch_get_main_queue(), block);
    }
}

I call it as follows inside of the success block of my background web call.

runOnMainQueueWithoutDeadlocking(^{
    [self.tableView beginUpdates];
    [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:1] withRowAnimation:UITableViewRowAnimationAutomatic];
    [self.tableView reloadSections:[NSIndexSet indexSetWithIndex:2] withRowAnimation:UITableViewRowAnimationAutomatic];
    [self.tableView endUpdates];
});