title: Numeric EditText and TextWatcher
body: <p>I have an decimal signed EditText (so it's impossible to write a comma). I put a TextWatcher on it but it only listen chars allowed to be written. </p>
  
  <p>However I want to catch when the user tries to write a comma to show a toast. </p>
  
  <p>How is it possible to do that? </p>
  
  <p>Thank you</p>