以编程方式添加UIBarButtonItem或编辑通过IB插入的UIBarButtonItem时出现问题

Hey all, I'm working on project that uses a tab bar at the bottom to flip through 5 sections of my app. One of these sections loads a map view which then spawns a web view. This was done with Round Rect Buttons at first, but they got in the way of the views, so I decided to switch to a navigation bar. In Interface Builder I inserted a navigation item and within it two Bar Button Items (left and right side). I've gotten the functionality for both button to work by control dragging from file's owner to fire the method associated with each button. This works fine and launches my web view, but what I would like to be able to do and have yet to figure out how to so far, is changing one of the buttons to a "done" or "back" button once in the web view. I've tried creating both buttons programmatically but neither would appear. This is the code I tried using to accomplish this...Hey all, I'm working on project that uses a tab