title: Android: How to use AlarmManager
body: <p>I need to trigger a block of code after 20 minutes from the <code>AlarmManager</code> being set.</p>
  
  <p>Can someone show me sample code on how to use an <code>AlarmManager</code> in ِAndroid?</p>
  
  <p>I have been playing around with some code for a few days and it just won't work.</p>