title: How should I keep the sharing variables in android?
body: <p>The work flow of my program is:</p>
  
  <ol>
  <li><p>Launch app </p>
  
  <ul>
  <li>Splash screen, check the server api, from the api get a list of file name</li>
  <li>Download some of the file in file list , remove the downloaded file name from the list</li>
  </ul></li>
  <li><p>App opened</p>
  
  <ul>
  <li>when the download is finished , jump to main page that will start download another file in the list</li>
  </ul></li>
  </ol>
  
  <p>The problem is , the list I was keep in the download manager , when I select don't leave activities in android setting , it will be killed. If I need a class that is some Data Class , that means I put a share data (A several hash map , array list) in it, and it keep updating (delete after async download finish) , and it never get killed. How can it be done? Thanks</p>