You can use a ready made implementation of a UITableView
with pull-to-refresh functionality.
Have a look at EGOTableViewPullRefresh or for a simpler implementation to PullToRefresh.
If you are interested in implementing this yourself, one approach is to add a subview to your UITableView
(e.g., UILabel
showing the "pull to refresh" message); then "intercept" the delegate methods when the user scrolls down (or up) and calculate whether the subview came into the viewable frame. Then issue the reload.
Another approach would be adding a last row to your table; then when the tableView:cellForRowAtIndexPath:
method of your data source is called, return a cell with the "pull to refresh" message and do the refresh.
But you will be better off using one of the suggested implementations.