You need to set a timer that ticks every 1/4 second or so and in the timer tick event check and compare the text. If it has not changed in the selected amount of time, save that data to where you need it and move the focus to another view or button. You can also disable the EditText if you need to.
Turn the timer on when the EditText gets focus and turn the timer off when the EditText loses focus or your condition of time passed has been reached.