title: getContentLength return -1 when i try to download zip file
body: <p>i try to download zip file from server and show progressBar, but i get <code>conexion.getContentLength()=-1</code>. That's why i can't show progress dialog, the downloading works fine. My code is below:</p>
  
  <pre><code>  URLConnection conection = fileUrl.openConnection();
    conection.connect();
    int lenghtOfFile = conection.getContentLength();
  </code></pre>