How can I fetch data from url by class name or id using Flutter?

Question

As you see in the title of the question, I need to fetch data from URL by class name or id in Flutter. There is some data I haven't got its JSON data, and I need them to display on my app. I could fetch data using the code in the below, but I can't fetch any data by class name or id because I don't know what I need to use. Please help me

class _MyHomePageState extends State<MyHomePage> {
  String stringResponse;

  Future fetcData() async {
    http.Response response;
    response = await http.get("www.example.com"); //Consider that the URL has just a string such as "This is a string."
    if (response.statusCode == 200) {
      setState(() {
        stringResponse = response.body;
      });
    } else {
      
    }
  }

  @override
  void initState() {
    // TODO: implement initState
    fetcData();
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Http request"),
      ),
      body: Center(
        child: Text(stringResponse.toString()),
      ),
    );
  }
}

Solution

here is package http package.

here is a complete method to get a response.

     HttpClient client = new HttpClient()
          ..badCertificateCallback =
              ((X509Certificate cert, String host, int port) => true);


     return client.getUrl(Uri.parse(url)).then((HttpClientRequest request) {
      request.headers.set('content-type', 'application/json-patch+json');
      request.headers.set('accept', 'application/json');
      var response = request.close().timeout(new Duration(seconds: 5));
      return response;
    }).then((HttpClientResponse response) {
      var result = response.transform(utf8.decoder).join();
      return result;
    }).catchError((onError) {
      var result = onError.transform(utf8.decoder).join();
      return result;
    });
  

Comments

[Tirth Patel]

Use FutureBuilder or add then callback for fetcData.

[Admin]

Sorry, I couldn't understand again how can I fetch by "class name" or "id". I guess your answer isn't about my question. In fact, my question is like that there are two paragraph in HTML, and I want to fetch the paragraph which has id's "p1".

[Tirth Patel]

Use some html parser library. pub.dev/packages/html

[Balasubramani Sundaram]

Could you please share the demo code of your response body.

[Admin]

@BalasubramaniSundaram Actually I haven't got any code in the body, I just considered there are string paragraphs. For example; <p id="p1">First string</p> <p id="p2">Second string</p> And I want to fetch first string by id.

[Admin]

@TirthPatel Thanks so much I'll check it out.

[Admin]

Thank you again. I solved my problem thanks to you. @TirthPatel Resolution: parse(response.body).getElementById("p3").text; I implemented html library and I used this parse method and my problem was solved.

[Tirth Patel]

That's Awesome! :D