Listen enter text

I need to write a mobile application that will listen for the phrase "enter text" reply "enter text now" while in a conversation and listen for the numbers 1 thru 100 and respond with a *.wav playback to respond to the number then continue listening for another number and respond to that number until you say exit at which time it will go back the the beginning and listen for the phrase "enter text" and again go into listening for the number via voice and respond with a message or song etc. The porgram will start when you press an Icon or somehow when the phone turns on. and will stay on listneing until you say quit voice app or something like that.