build method Null safety

Implementation

@override
Widget build(BuildContext context) {
  switch (knowledgePanelElement.elementType) {
    case KnowledgePanelElementType.TEXT:
      return _KnowledgePanelTextElementCard(
        textElement: knowledgePanelElement.textElement!,
      );
    case KnowledgePanelElementType.IMAGE:
      return Image.network(
        knowledgePanelElement.imageElement!.url,
        width: knowledgePanelElement.imageElement!.width?.toDouble(),
        height: knowledgePanelElement.imageElement!.height?.toDouble(),
      );
    case KnowledgePanelElementType.PANEL:
      return KnowledgePanelCard(
        panel: allPanels
            .panelIdToPanelMap[knowledgePanelElement.panelElement!.panelId]!,
        allPanels: allPanels,
      );
    case KnowledgePanelElementType.PANEL_GROUP:
      return KnowledgePanelGroupCard(
          groupElement: knowledgePanelElement.panelGroupElement!,
          allPanels: allPanels);
    case KnowledgePanelElementType.TABLE:
      return KnowledgePanelTableCard(
        tableElement: knowledgePanelElement.tableElement!,
      );
    case KnowledgePanelElementType.MAP:
      return KnowledgePanelWorldMapCard(knowledgePanelElement.mapElement!);
    case KnowledgePanelElementType.UNKNOWN:
      return EMPTY_WIDGET;
  }
}