title: Implement picture password in Android app
body: <p>I want to secure my app using a password like on this picture:</p>
  
  <p><a href="https://i.stack.imgur.com/quONx.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/quONx.jpg" alt="picture"></a><br>
  <sub>(source: <a href="https://www.karganys.fr/wp-content/uploads/2010/12/android-pattern-lock-266x400.jpg" rel="nofollow noreferrer">karganys.fr</a>)</sub>  </p>
  
  <p>is there already a class that i can use or i must create by myself?
  i don't find anything about this....  </p>