title: How to prevent going back to the previous activity?
body: <p>When the BACK button is pressed on the phone, I want to prevent a specific activity from returning to its previous one.</p>
  
  <p>Specifically, I have login and sign up screens, both start a new activity called <code>HomeScreen</code> when successful login/signup occurs. Once HomeScreen is started, I want to prevent the users from being able to return to the login or sign up screens by pressing the BACK key. </p>
  
  <p>I tried using <code>Intent.FLAG_ACTIVITY_NO_HISTORY</code>, but since the application has Facebook integration, when the 'Login with Facebook' is used, Facebook should return to the initial login screen, therefore I should keep a history of these activities.</p>
  
  <p>I thought of overriding the behaviour of the BACK button on <code>HomeScreen</code> to directly finish an application when the button is pressed and I used</p>
  
  <pre><code>@Override
  public void onBackPressed() {
      finish();
  }
  </code></pre>
  
  <p>but that also does not work.</p>