title: How to fix android error 'Color value must start with #'?
body: <p>I was trying to use an icon from <a href="https://design.google.com/icons/index.html" rel="nofollow noreferrer">this page</a> in my layout as follows</p>
  
  <pre><code>&lt;ImageButton
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:src="@drawable/ic_backspace_black_24dp"
  /&gt;
  </code></pre>
  
  <p>but it could not be rendered because of an error </p>
  
  <pre><code>Color value '@drawable/ic_backspace_black_24dp' must start with #
  </code></pre>
  
  <p>I found two related issues in SO <a href="https://stackoverflow.com/questions/20599262/color-value-drawable-resource-issue">here</a> and <a href="https://stackoverflow.com/questions/21971573/setting-drawable-as-text-color-raise-an-exception-color-value-must-start-with">here</a> which did not help resolve the issue. </p>
  
  <p>There is no dash ('-') in the filename, the file-format is a 'png' and there is no <code>res/color</code> directory in my project. </p>
  
  <p>All my colors defined in <code>colors.xml</code> start with a <code>#</code>.</p>
  
  <p>So how to fix this error? </p>