title: List all files, recursively, in Android Dropbox API
body: <p>How can I list <strong>all files, recursively</strong> in DropBox folder?
  I tried code below but returns no result:</p>
  
  <pre><code>result = dbxClient.files().search("", "*");
  </code></pre>
  
  <p>And this returns files in path, not subfolders:</p>
  
  <pre><code>result = dbxClient.files().listFolder(path);
  </code></pre>