Intercepting app http requests
I was struggling with the same issue for a while. Finally, found a way out to track traffic coming from the emulator. You can start the emulator using:

emulator -avd &lt;emuName&gt; -http-proxy http://&lt;SYSTEM_IP&gt;:&lt;PORT&gt;

where emuName should be replaced with your emulator instance's name; SYSTEM_IP should be replaced with your system's IP address and PORT should be the port where the interceptor is running.

You can take a look at this: 
http://stick2code.blogspot.in/2014/04/intercept-http-requests-sent-from-app.html.
Hope it helps!