I would like to implement rich format text views as are demonstrated in Instagram. Following is a screenshot.
Specifically, my goals are:
- Words at different positions of the same text view may have different font sizes, font colors and font styles(bold, italic, etc).
- Touch events (long press, touch down, etc) can be detected in the delegate callbacks. Information (which word is touched, whether it’s a long press or a touch down, etc) can be gathered in such callback methods.
Big frameworks like Three20 are out of the question. Small, independent libraries are highly preferred. Low level Cocoa Touch APIs may also be OK if it won’t take me more than a few days to wrap them up.
Any suggestions are highly appreciated.

Finally found an ideal open source solution (supports both iOS 5.0 and iOS 6): the OHAttributedLabel, which is capable of both rich format and touch handling.
https://github.com/AliSoftware/OHAttributedLabel