build method Null safety

Implementation

@override
Widget build(BuildContext context) {
  final ThemeData themeData = Theme.of(context);
  Color? colorFromEvaluation;
  if (knowledgePanelTitleElement.iconColorFromEvaluation ?? false) {
    if (themeData.brightness == Brightness.dark) {
      colorFromEvaluation = _getColorFromEvaluationDarkMode(evaluation);
    } else {
      colorFromEvaluation = _getColorFromEvaluation(evaluation);
    }
  }
  List<Widget> iconWidget;
  if (knowledgePanelTitleElement.iconUrl != null) {
    iconWidget = <Widget>[
      Expanded(
        flex: IconWidgetSizer.getIconFlex(),
        child: Center(
          child: AbstractCache.best(
            iconUrl: knowledgePanelTitleElement.iconUrl,
            width: 36,
            height: 36,
            color: colorFromEvaluation,
          ),
        ),
      ),
      const Padding(padding: EdgeInsets.only(left: SMALL_SPACE)),
    ];
  } else {
    iconWidget = <Widget>[];
  }
  return Padding(
    padding: const EdgeInsets.only(
      top: VERY_SMALL_SPACE,
      bottom: VERY_SMALL_SPACE,
    ),
    child: Row(
      children: <Widget>[
        ...iconWidget,
        Expanded(
          flex: IconWidgetSizer.getRemainingWidgetFlex(),
          child: LayoutBuilder(
            builder: (BuildContext context, BoxConstraints constraints) {
              return Wrap(
                direction: Axis.vertical,
                children: <Widget>[
                  SizedBox(
                    width: constraints.maxWidth,
                    child: Text(
                      knowledgePanelTitleElement.title,
                      style: TextStyle(color: colorFromEvaluation),
                    ),
                  ),
                  if (knowledgePanelTitleElement.subtitle != null)
                    SizedBox(
                      width: constraints.maxWidth,
                      child: Text(knowledgePanelTitleElement.subtitle!)
                          .selectable(),
                    ),
                ],
              );
            },
          ),
        ),
        const Icon(
          Icons.keyboard_arrow_down_outlined,
        ),
      ],
    ),
  );
}