Clearing input text boxes for iOS apps

I'm making an app for iOS (iPad specifically) and am having an issue.  I have an input text box in my app called 'answer' - when a user types in a correct answer I need the text box to go blank again so they can enter another one.  This works fine typically by simply doing answer.text = "";  however when publishing this app with Air for iOS, when a user types in an answer the input text box does NOT clear itself - the answer remains in it (the quiz does respond to the correct answer so it does read in the input text fine), however answer.text = "" for some reason does not clear the text box in the app when testing it on my iPad.  Any clues on this?  Thanks in advance.