This may not be a programming question, but I don't know where to ask for this and it's still related.
We all know that the checkbox and drop-down menu is a UI paradigm brought in from HTML or web interface.
I'm not asking for code implementations here. A google search had produced many results. Although if anyone is willing to share that's great.
So the question is: Is this a good design approach if we just want to provide a checkbox or drop-down functionality? (e.g. for quizzes, or forms)
My personal opinion is that creating a checkbox or drop-down menu UI element would be a non-standard approach to how the iPhone UI is supposed to look & feel across all apps.
You should consider an approach that uses table views instead, with drill-downs into another table view, and use the checkmark accessory to indicate a selected element out of a set.
If you absolutely must use checkboxes and drop-down menus, you should consider embedding an HTML page with those elements instead.
As far as drop-downs are concerned you always have the option of the UIPicker, which can be easily embedded in a UIActionSheet. I've used this setup in the app I'm developing and it works great.
Check boxes map directly to UISwitch elements, if they make sense for the data you are using.