问TypeError:网络请求失败

EN

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

const connection = mysql.createPool({
  host     : 'localhost',
  user     : 'root',
  password : '',
  database : 'mangareader'
});
const app = express();

// Creating a GET route that returns data from the 'users' table.
app.get('/manga', function (req, res) {
    // Connecting to the database.
    connection.getConnection(function (err, connection) {

    // Executing the MySQL query (select all data from the 'users' table).
    connection.query('SELECT * FROM manga', function (error, results, fields) {
      // If some error occurs, we throw an error.
      if (error) throw error;

      // Getting the 'response' from the database and sending it to our route. This is were the data is.
      res.send(results)
    });
  });
});

// Starting our server.
app.listen(3000, () => {
 console.log('Go to http://localhost:3000/manga so you can see the data.');
});

import React, {Component} from 'react';
import {
    FlatList,
    StyleSheet,
    View,
    Text,
    ActivityIndicator,
  } from 'react-native'; 


  export default class MangaList extends Component {

    constructor(props){
        super(props);
        this.state ={ isLoading: true}
      }

      componentDidMount(){
        return fetch('192.168.1.5:3000/manga')
          .then((response) => response.json())
          .then((responseJson) => {

            this.setState({
              isLoading: false,
              dataSource: responseJson.manga,
            }, function(){

            });

          })
          .catch((error) =>{
            console.error(error);
          });
      }



      render(){

        if(this.state.isLoading){
          return(
            <View style={{flex: 1, padding: 20}}>
              <ActivityIndicator/>
            </View>
          )
        }

        return(
          <View style={styles.container}>
            <FlatList
              data={this.state.dataSource}
              renderItem={({item}) => <Text>{item.manga_name}, {item.manga_des}</Text>}
              keyExtractor={({id}, index) => manga_id}
            />
          </View>
        );
      }
    }
  const styles = StyleSheet.create({
      container: {
          marginTop: 15,
          flex: 1,
          justifyContent: 'center',
          alignItems: 'center',
          backgroundColor: '#F5FCFF'
      },
  });