title: Exit/Finish an app/activity - android
body: <p>I've got 4 activities say <code>Act1</code>, <code>Act2</code>, <code>Act3</code> and <code>Act4</code>.
  A button in Act1 opens Act2, a button in Act2 opens Act3, a button in Act3 opens Act4.</p>
  
  <p>I want two things to be done:</p>
  
  <ol>
  <li><p>I've a button in Act4 which directs the user to Act1, the prob is when the user clicks back in Act1, i want to close the app instead of opening the Act4..</p></li>
  <li><p>I've option in menu 'exit' in all activities when the user choose it, i want to close the app instead of going back to previous activity.</p></li>
  </ol>
  
  <p>Tried using <code>finish();</code> but it didn't meet my requirements.</p>