title: Flutter specify Button Theme for each button type
body: <p>I am working on a <code>Flutter</code> app and need to specify custom <code>ButtonTheme</code> for each button type, i.e. raised, outlined and flat.</p>
  <p>The parameter I found in <code>ThemeData</code> class is only <code>buttonTheme</code>, and this has <code>ButtonThemeData</code> that is defined for all buttons:</p>
  <pre><code>static ThemeData darkTheme = ThemeData(
     buttonTheme: const ButtonThemeData(
        colorScheme: ColorScheme(
          primary: Color(Constants.PrimaryColor),
          primaryVariant: Color(Constants.PrimaryVariant),
        ),
        textTheme: ButtonTextTheme.normal,
      ),
  )
  </code></pre>
  <p>The question now, how can I define a separate theme for each button type to change, for example, background and text color?</p>