flutter :将TextEditingController放入json body

import 'dart:convert';

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  final TextEditingController _controller = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter TextEditingController Example'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              TextField(
                controller: _controller,
                decoration: InputDecoration(
                  labelText: 'Enter some text',
                ),
              ),
              RaisedButton(
                child: Text('Send JSON body'),
                onPressed: () {
                  Map<String, dynamic> requestBody = {
                    'text': _controller.text,
                  };

                  String jsonBody = jsonEncode(requestBody);

                  // Send the JSON body to the server
                  // ...
                },
              ),
            ],
          ),
        ),
      ),
    );
  }
}