null - 使用 globalKey 从另一个类访问 textEditingController

Question

启动应用程序时出现此错误。我理解错误，但我不知道如何找到错误。请帮我纠正错误。

class NoteCardWidget extends StatefulWidget {
final NotedB note;

const NoteCardWidget({
Key? key,
required this.note,
 }) : super(key: key);

  @override
State<NoteCardWidget> createState() => _NoteCardWidgetState();
}

  class _NoteCardWidgetState extends State<NoteCardWidget> {
 final controllerKey = GlobalKey<NoteDetailsState>();
          

  @override
   Widget build(BuildContext context) {
return SafeArea(
  child: Scaffold(
    backgroundColor: const Color(0xFFF4E0F7),
    appBar: AppBar(
      iconTheme: const IconThemeData(color: Colors.black),
      backgroundColor: Colors.transparent,
      actions: [
        IconButton(
            key: controllerKey,
            onPressed: () async {
              setState(() {
             
                widget.note.title =
                    controllerKey.currentState!.titleController.text;
                widget.note.description =
                    controllerKey.currentState!.descController.text;
              });
              Navigator.push(
                  context,
                  MaterialPageRoute(
                    builder: (_) => NoteDetails(
                      noteId: widget.note.id,
                    ),
                  ));
            },
            icon: const Icon(
              Icons.edit,
            )),
        TextButton(
            onPressed: () async {
              await Databahelper.instance.deleteNote(widget.note.id!);
              Navigator.pop(context);
            },
            child: const Icon(
              Icons.delete,
              color: Colors.black,
            )),
      ],
      elevation: 0,
      leading: IconButton(
          onPressed: () {
            Navigator.pop(context);
          },
          icon: const Icon(Icons.arrow_back)),
    ),

    //**********************************AppBar*********************************** */

    body: SingleChildScrollView(
      child: Center(
          child: Padding(
        padding: const EdgeInsets.all(15.0),
        child: Column(
          children: [
            const SizedBox(
              height: 25,
            ),
            Text(widget.note.title,
                style: const TextStyle(
                    fontSize: 30, fontWeight: FontWeight.bold)),
            const SizedBox(height: 15),
            Text(
              widget.note.description,
              style: const TextStyle(
                fontFamily: 'fonts/Schyler-Regular.ttf',
                fontSize: 24,
              ),
            ),
          ],
        ),
      )),
    ),
  ),
);
}
  }

当我删除 setState() 方法中的请求时，我不再有错误，但我不知道通过什么其他方式访问这些变量。有人有建议吗？