Sample code for useFocusNode for flutter hooks

custom_text_form_field.dart

import 'package:flutter/material.dart';
import 'package:flutter_hooks/flutter_hooks.dart';

class CustomTextFormField extends HookWidget {
  CustomTextFormField({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final _focusNode = useFocusNode();
    final _controller = useTextEditingController();

    _focusNode.addListener(() {
      debugPrint("Focus Change : " + _focusNode.hasFocus.toString());
    });

    return Container(
      child: TextFormField(
        maxLines: null,
        minLines: 500,
        focusNode: _focusNode,
        controller: _controller,
      ),
    );
  }
}