title: Add character automatically in EditText after 6 letters
body: <p>I want to automatically put a "-" after 6 letters in my EditText and I want the user can continue to write after the "-".
  (I want the user writes : 1234562 and it appears 123456-2 in the EditText).</p>
  
  <p>But I don't know how to do this and if it is possible. If you can help me, thanks </p>