如何将React native form连接到express后端

const express = require('express');
const app = express();

// 添加路由和中间件

app.listen(3000, () => {
  console.log('Express server is running on port 3000');
});

import React, { useState } from 'react';
import { View, TextInput, Button } from 'react-native';

const App = () => {
  const [inputValue, setInputValue] = useState('');

  const handleSubmit = () => {
    // 在此处将表单数据发送到Express后端
  };

  return (
    <View>
      <TextInput
        value={inputValue}
        onChangeText={text => setInputValue(text)}
      />
      <Button title="Submit" onPress={handleSubmit} />
    </View>
  );
};

export default App;

const handleSubmit = () => {
  fetch('http://your-express-backend.com/submit-form', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({ formData: inputValue }),
  })
    .then(response => response.json())
    .then(data => {
      // 处理从后端返回的响应数据
    })
    .catch(error => {
      console.error('Error:', error);
    });
};

const express = require('express');
const bodyParser = require('body-parser');
const app = express();

app.use(bodyParser.json());

app.post('/submit-form', (req, res) => {
  const formData = req.body.formData;
  // 处理表单数据并发送响应
});

app.listen(3000, () => {
  console.log('Express server is running on port 3000');
});