title: Crashlytics found an invalid API key
body: <p>When I am trying to build project with <code>value</code> of <code>meta-data</code> tag as a string reference, crashlytics fail with following error:</p>
  
  <pre><code>Crashlytics found an invalid API key: @string/crashlytics. 
  Check the Crashlytics plugin to make sure that the application has been added successfully! 
  Contact support@crashlytics.com for assistance.
  </code></pre>
  
  <p><strong>Doesn't work</strong></p>
  
  <pre><code>&lt;meta-data
      android:name="com.crashlytics.ApiKey"
      android:value="@string/crashlytics"/&gt;
  </code></pre>
  
  <p><strong>Works</strong></p>
  
  <pre><code>&lt;meta-data
      android:name="com.crashlytics.ApiKey"
      android:value="1234567890..."/&gt;
  </code></pre>
  
  <p>I am want to define different keys inside <code>string.xml</code> for different <code>productFlavors</code> of my android project.</p>
  
  <h1>Update</h1>
  
  <p>After writing to crashlytics support:</p>
  
  <blockquote>
    <p>Currently we only are able to evaluate the AndroidManifest.xml at build time so we don't look at any strings resources so we only support a hard coded string. I'll definitely share this with the team that you're interested so we can look into supporting this in a future release.</p>
  </blockquote>