title: Android : resValue variables could not be resolved in Gradle
body: <p>I am following an android example from vogella.com about Retrofit. </p>
  
  <p><a href="http://www.vogella.com/tutorials/Retrofit/article.html" rel="nofollow noreferrer">http://www.vogella.com/tutorials/Retrofit/article.html</a></p>
  
  <p>I get stuck where one is supposed to do the following:</p>
  
  <p>add the stackapp id and key</p>
  
  <p>According to Vogella</p>
  
  <p><em>After you registered your application, you get a Client Id and a Key . As   we want to keep them out of a possible version control system, we import them  into our project using gradle. To do so, go to your gradle home directory  (.gradle/ in your users home directory) and paste the following lines into your  gradle.properties file (create one, if you can’t find it). Of course, replace  yourKey and yourClientId with your corresponding values from Stackapps.</em></p>
  
  <p>I went to this directory and created a new file</p>
  
  <pre><code>gradle.properties
  </code></pre>
  
  <p>and in that file I added the keys</p>
  
  <pre><code>key=xxxxxxxx
  client_id=xxxx
  </code></pre>
  
  <p>and then in the gradle.properties i added the following in deafultconfig {</p>
  
  <pre><code> resValue("string", "key", project.key)
   resValue("string", "client_id", project.client_id)
  </code></pre>
  
  <p>But both the key and the client_id's could not be resolved.</p>
  
  <p>What could the solution be to this?</p>