how to access my 127.0.0.1:8000 from android tablet
You can find out what the ip address of your PC is with the ipconfig command in a Windows command prompt.  Since you mentioned them being connected over WiFi look for the IP address of the wireless adapter.
Since the tablet is also in this same WiFi network, you can just type that address into your tablet's browser, with the :8000 appended to it and it should pull up the page.
I am developing a webpage in django (on my pc with windows 7) and now i need to test some pages in tablet pcs. suddenly the thought came if i can have an access to my localhost in windows from android tablet. is that possible? I am in the same wifi connection in both devices at home. 
i read a lot questions and answers regarding this issue in stackoverflow and other places, but none of them gave me some concrete solutions. 
I have samsung tab 2 10.1 with android 4.0.4.
appreciate any help, thanks