As a part of the course Android NanoDegree available at www.udacity.com this project is created. Please insert your API key in this file : Popular-Movies/app/src/main/res/values/strings.xml
<resources>
...
<string name="action_settings" translatable="false">Settings</string>
<string name="api_key" translatable="false">[YOUR_API_KEY]</string>
<string name="popularity" translatable="true">Popularity</string>
...
</resources>