title: How to reference theme attributes in Jetpack Compose?
body: <p>So in the current andriod development, if we need to reference to a color set in the theme, we could simply do: (in layout xml)</p>
  <pre><code>....
      &lt;TextView
          ...
          android:textColor=&quot;?attr/colorPrimary&quot;
          .../&gt;
  ....
  </code></pre>
  <p>If I set a color blue in the theme. I will get that color in the textview above.</p>
  <p>I was wondering how I could do the same in <code>Jetpack Compose</code>. In <code>Compose</code>, we do,</p>
  <pre><code>MaterialTheme(...) {
      Column {
          Text(
              ...
              textStyle = TextStyle(color = ????) // How to I reference to the theme?
          )
      }
  }
  </code></pre>