It's possible with a TextView to get notified when some changes are made within it by implementing a TextWatcher and pass it to the instance of the TextView. This is largely used with EditText (extends TextView) to interact with user events on this view.

See TextWatcher interface here : http://developer.android.com/reference/android/text/TextWatcher.html
See EditText class here : http://developer.android.com/reference/android/widget/EditText.html

I think we could introduce three new annotations : @BeforeTextChanged @TextChanged @AfterTextChanged