title: Unable to work with emulator, using react-native and expo
body: <p>I am using react native with expo, OS: Elementary OS, Emulator: Android Studio emulator.</p>
  
  <p>getting the following error when trying to open the app in emulator</p>
  
  <pre><code>12:58:16: Starting Android...
  Error running adb: Error running app. Error: Activity not started, unable to resolve Intent { act=android.intent.action.VIEW dat=exp://192.168.0.101:19000 flg=0x10000000 }
  
  
   › Press a to open Android device or emulator, or i to open iOS emulator.
   › Press q to display QR code.
   › Press r to restart packager, or R to restart packager and clear cache.
   › Press d to toggle development mode. (current mode: development)
  
  (node:15266) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'length' of null
      at /xdl/src/Android.js:90:18
      at Generator.next (&lt;anonymous&gt;)
      at step (/home/afzal/AFZAL/Cloud_Drive/Development/React Native/react-native-boilerplate-redux-flow-master/node_modules/xdl/build/Android.js:475:191)
      at /home/afzal/AFZAL/Cloud_Drive/Development/React Native/react-native-boilerplate-redux-flow-master/node_modules/xdl/build/Android.js:475:361
      at &lt;anonymous&gt;
      at process._tickCallback (internal/process/next_tick.js:160:7)
  (node:15266) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
  </code></pre>