Android beginner Graphical layout not working

I get the following error, when i create an android project and go to the Graphical layout section in the main.xml file. I don't see the black gu开发者_运维问答i screen as show in this image. I get the following warning/error. What should i do to resolve this ?

The project target (Android 3.0) is still loading. main.xml will refresh automatically once the process is finished.

---

Update your ADT. For that got to Eclipse -> Check for updates.

That should fix your issue.