title: react-native run-android stop working by the sudden
body: <p>In the past weeks, I have been using react-native run-android to test my android app in android emulator successfully. </p>
  
  <p>Yesterday, I tried to generate a signed APK by following the link <a href="https://facebook.github.io/react-native/docs/signed-apk-android.html#content" rel="nofollow">https://facebook.github.io/react-native/docs/signed-apk-android.html#content</a>, the signed APK does work in my cellphone.  </p>
  
  <p>Today, when I try to run react-native run-android again to test new features in emulator, the packager run successfully, Android emulator report "ReferenceError can't find variable _fbBatchedBridge(line 1 in the generated bundle), when I hit "RELOAD JS",  it report "Unable to download JS bundle, did you forget to start development server or connect your device? </p>
  
  <p>I even tried to change the DEV settings by adding the ip:8081, still no luck.  </p>
  
  <p>Could anyone help on this, thanks a lot  </p>