title: Using colors.xml in any Layout in Android
body: <p>I have a <code>colors.xml</code> in res/value </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;resources&gt;
      &lt;color name="colorPrimary"&gt;#3F51B5&lt;/color&gt;
      &lt;color name="colorPrimaryDark"&gt;#303F9F&lt;/color&gt;
      &lt;color name="colorAccent"&gt;#FF4081&lt;/color&gt;
      &lt;color name="indicator_unselected"&gt;#4D000000&lt;/color&gt;
      &lt;!--Indigo 500--&gt;
      &lt;color name="primary_500"&gt;#3F51B5&lt;/color&gt;
      &lt;!--Indigo 700--&gt;
      &lt;color name="primary_700"&gt;#303F9F&lt;/color&gt;
      &lt;!--Pink 500--&gt;
      &lt;color name="accent_500"&gt;#E91E63&lt;/color&gt;
      &lt;!--Pink 700--&gt;
      &lt;color name="accent_700"&gt;#C2185B&lt;/color&gt;
      &lt;color name="black_trans80"&gt;#33000000&lt;/color&gt;
  
      &lt;color name="blue_grey"&gt;#455A64&lt;/color&gt;
      &lt;color name="red"&gt;#F44336&lt;/color&gt;
      &lt;color name="pink"&gt;#E91E63&lt;/color&gt;
      &lt;color name="purple"&gt;#9C27B0&lt;/color&gt;
      &lt;color name="deep_purple"&gt;#673AB7&lt;/color&gt;
      &lt;color name="indigo"&gt;#3F51B5&lt;/color&gt;
      &lt;color name="blue"&gt;#2196F3&lt;/color&gt;
      &lt;color name="light_blue"&gt;#03A9F4&lt;/color&gt;
      &lt;color name="cyan"&gt;#00BCD4&lt;/color&gt;
      &lt;color name="teal"&gt;#009688&lt;/color&gt;
      &lt;color name="green"&gt;#4CAF50&lt;/color&gt;
      &lt;color name="light_green"&gt;#8BC34A&lt;/color&gt;
      &lt;color name="lime"&gt;#CDDC39&lt;/color&gt;
      &lt;color name="yellow"&gt;#FFEB3B&lt;/color&gt;
      &lt;color name="amber"&gt;#FFC107&lt;/color&gt;
      &lt;color name="orange"&gt;#FF9800&lt;/color&gt;
      &lt;color name="deep_orange"&gt;#FF5722&lt;/color&gt;
      &lt;color name="brown"&gt;#795548&lt;/color&gt;
      &lt;color name="grey"&gt;#E0E0E0&lt;/color&gt;
  
      &lt;color name="white_70"&gt;#B3FFFFFF&lt;/color&gt;
      &lt;color name="cyan_50"&gt;#E0F7FA&lt;/color&gt;
      &lt;color name="amber_50"&gt;#FFF8E1&lt;/color&gt;
      &lt;color name="purple_50"&gt;#F3E5F5&lt;/color&gt;
  &lt;/resources&gt;
  </code></pre>
  
  <p>When I want to use any of these colors in a layout, let's take <code>listview.xml</code> (a layout that contains a listview).</p>
  
  <p>I have a LinearLayout and a ListView in it.
  So, If I want to change the background color of the LinearLayout I have to do something like this:</p>
  
  <pre><code>android:background="@color/cyan"
  </code></pre>
  
  <p>This works. My question is: My file is called color<strong>s</strong>.xml not color.xml
  Why can I still access these custom colors by using @color? Why is @colors giving me an error?</p>