I was updated my android SDK tools to 24.1.2 and I updated to Android API 22 (that is, 5.1) and I restarted my eclipse and created new android project with target API of 22 then when I was opened my XML file it was not showing any preview. It was showing an error:
This version of the rendering library is more recent than your version of ADT plug-in. Please update ADT plug-in.
Go to Help >> Install new software and add install https://dl-ssl.google.com/android/eclipse/ then select Developer Tools and click on next to begin install
or
Change the API version in XML.