title: why do we use 10.0.2.2 to connect to local web server instead of using computer ip address in android client
body: <p>We normally use 10.0.2.2:(port number) in the url to connect to the local web server,but we should use the computer's ip address instead of 10.0.2.2</p>
  
  <p>Then why do we use 10.0.2.2?</p>