I have a few UITableViews that gather their content from remote XML files. Sometimes the file is updated, but the view is not updated, because I load the file in my viewDidLoad method.

I am assuming I should do a check in viewDidAppear and load my XML file again. But I don't want it loading every time the user clicks back to that view.

What is the best way to do this? Can I somehow check the updated date of a remote file on the web? Or should I store the updated date in my app, then check at an interval? There must be a preferred way to do this, so that I know that the XML file has been updated.

Thanks.