Mobile for Jira do support SAML 2.0, but you need to apply the following:

Steps to login using SAML / ADFS:

  1. Click on SSO label, username and password fields will disappear.
  2. Copy the link that you usually used to login to your instance from the web browser and paste it in URL field.
  3. Click login, you'll be redirected to your instance to login (This procedure may take a few minutes for your site to load).