Properly log out a user from android app
<p>I'm developing a small android app, and basically so far it just has login and logout functionality. I'm using Firebase to store user data and also for authentication. </p>

<p>So I have login working and it authenticates users as it should and I have logging out working in the sense that it <code>unauthenticates</code> users. But is there anything I have to do from within the app to kill the session? </p>

<pre><code>if (id == R.id.action_log_out) {
    ref.unauth(); //End user session
    startActivity(new Intent(MainActivity.this, LoginActivity.class)); //Go back to home page
    finish();
}        
</code></pre>

<p>Will this work as I think it should?  Obviously if someone logs out they shouldn't be able to hit th back button and magically go back to the last page without re-logging in. </p>