如何将静态单元(文本)添加到Flutter中的TextFormField？

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  final TextEditingController _controller = TextEditingController(text: '静态单元');

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('TextFormField 示例'),
        ),
        body: Center(
          child: Padding(
            padding: EdgeInsets.all(16.0),
            child: TextFormField(
              controller: _controller,
              decoration: InputDecoration(
                labelText: '文本输入',
              ),
            ),
          ),
        ),
      ),
    );
  }
}