title: How do I set the animation color of a LinearProgressIndicator?
body: <p>The <a href="https://docs.flutter.io/flutter/material/LinearProgressIndicator-class.html" rel="noreferrer">LinearProgressIndicator documentation</a> helpfully displays the existence of a valueColor property and even mentions &quot;To specify a constant color use: new AlwaysStoppedAnimation(color).&quot;, but if I try to set the color I get an error that LinearProgressIndicator has no instance setter for valueColor and the constructor for the class only accepts a key and a numerical value for the progress amount.</p>
  <p>If I want a LinearProgressIndicator with a custom color do I need to create my own class? Is there really no way to specify this?</p>