title: Google map is not appearing in android device
body: <p>I am working on Google Maps v2 with Android SDK version 19. I included <code>google-play-services_lib</code> into my project.<br>
  My project was working fine but when I updated google-play-services_lib my project stopped working. There is no error in my project but it is giving exception on runtime. The updated version of google-play-service_lib is 20.  </p>
  
  <p>Secondly I was following  <a href="https://developers.google.com/maps/documentation/android/start" rel="nofollow">https://developers.google.com/maps/documentation/android/start</a> site here is two line code: </p>
  
  <pre><code>&lt;meta-data
      android:name="com.google.android.gms.version"
      android:value="@integer/google_play_services_version" /&gt;
  </code></pre>
  
  <p>I do not understand what should be written in the value field ? </p>