title: no main manifest attribute error after add volley.jar library
body: <p>i could not build my project because of "no main manifest attribute" error</p>
  
  <p>1)i copied volley.jar in libs folder</p>
  
  <p>2)right clicked volley, clicked "add as library" then choosed "project library"</p>
  
  <p>3)add &lt;'application
              android:name="com.example.docar.app.AppController".../>' to AndroidManifest.xml</p>
  
  <p>still got problem.</p>
  
  <p>screen shot
  <img src="https://i.stack.imgur.com/naV6q.png" alt="screen shot"></p>