Question

I have a custom UITableViewCell that extends UITableViewCell and implements MFMailComposeViewControllerDelegate. (i.e. UITableViewCell<MFMailComposeViewControllerDelegate>).

When a button is clicked in the custom table cell, I present a mailController with presentModalViewController. The user can then type the email or cancel, everything works.

But when didReceiveMemoryWarning is called while the mailController is present, and then when the mailController closes, the app crashes. I get this error:

“-[CustomCell respondsToSelector:]: message sent to deallocated instance 0xf4988b0”

Now I’m pretty sure its because the table view that owns the tablecell has been deallocated hence the cell has been deallocated but does anyone have any suggestions to go about fixing this? I mean I guess I could switch the MailCompose delegate to the table cell’s table view’s view controller but I’d rather not. I’d rather keep it in the table cell. Any ideas?

Answer 1

You should not be using a table view cell as the MFMailComposeViewControllerDelegate. Because of the nature of cells and their reuse, it’s hard to pin a particular instance to be a delegate, especially a delegate of a view controller on top of the view controller the cell is being shown, and on this particular case, the memory warning might be causing a flush of the cache of cells.

The MFMailComposeViewControllerDelegate should be the delegate of the table view where the cell is. It’s also a better MVC pattern.