El documento describe cómo realizar el análisis de HTML en el desarrollo de aplicaciones móviles usando Flutter para plataformas Android e iOS. A través de bibliotecas como jsoup y plugins como flutter_html, los desarrolladores pueden extraer y procesar información del código HTML, como títulos, párrafos y enlaces. Además, se proporcionan ejemplos de código que demuestran la implementación de estas técnicas en aplicaciones Flutter.

2. HTML Parsing in FLUTTER for Android / iOS
Development
The HTML parser is the structured markup processing tool defining the
HTML Parser class. It is often accessed to parse HTML files. Parsing is to
resolve into component parts and then describe their syntactic roles.
In general, parsing analyzes the String of the symbols in computer or
natural languages. When speaking about HTML parsing, it takes the
HTML code and extracts the relevant information, such as the page’s
title, headings, paragraphs, links, bold text, and much more.
Keep reading this article to learn much about HTML parsing in Flutter
for android or iOS platforms! If you need professional assistance, do
not hesitate to contact the reputable and trustworthy Flutter app
development company.

3. Introduction to flutter HTML
Flutter is an open-source, cross-platform mobile app development
framework. It is highly compatible with the present web rendering
technologies such as HTML, JavaScript, and CSS.
Therefore, it is a perfect platform for web and mobile app
development. With the help of Flutter developers, you can compile the
existing code into the client experience, implant it into the browser and
finally deploy it to any web server.

4. When you build the application with Flutter and need to render some
HTML content, you can do it easily by accessing the plugin flutter_html.
You can add flutter_html and its latest version to the dependencies
section in pubspec.yaml file using the command “flutter pub add
flutter_html.” Then, you have to use “flutter pub get” to execute the
command.

5. How to do HTML parsing in Flutter
Android developers use the Jsoup library to parse HTML text and code.
But, developers new to the flutter mobile app development do not
know the existence of such a library to parse HTML text and code from
the website in Flutter.
So, are you thinking about the right way to perform HTML parsing in
Flutter for Android or iOS development? Well! Here are the two
different solutions to meet your demands.

6. Solution: 1
You can now parse the HTML string in this way.
import ‘package:html/parser.dart’;
//here goes the function
String _parseHtmlString(String htmlString) {
var document = parse(htmlString);
String parsedString = parse(document.body.text).documentElement.text;
return parsedString;
}
Solution: 2
Next, you have to fetch data using http.get(url) to the user parser, and
then you can parse whatever you want. Follow the below-mentioned
code properly.

7. Fetch HTML page:
Future<string> fetchHTML(String url) async {
final response = await http.get(url);
if (response.statusCode == 200)
return response.body;
else throw Exception('Failed');
}</string>
After that, you should call FutureBuilder()

8. FutureBuilder< String>(
future: fetchHTML('http://your_page.ru/page.html'),
builder: (context, snapshot){
if (snapshot.hasData) {
//Your downloaded page
_temp = snapshot.data;
print(snapshot.data);
return Text('Finished');
}
else if (snapshot.hasError)
return Text('ERROR');
return Text('LOADING');
},
),

9. Now, you can parse it:
parse(_temp);
Other ways to parse HTML in Flutter
Method: 1
Are you accessing Flutter? Do you wish to parse HTML using
parser.dart? If yes, then run the following code.

10. <div class="weather-item now">
<span class="time">Now</span>
<div class="temp">19.8<span>℃</span>
<small>(23℃)</small>
</div>
<table>
<tbody><tr>
<th><i class="icon01" aria-label="true"></i></th>
<td>93%</td>
</tr>
<tr>
<th><i class="icon02" aria-label="true"></i></th>
<td>south 2.2km/h</td>
</tr>
<tr>
<th><i class="icon03" aria-label="true"></i></th>
<td>-</td>
</tr>
</tbody></table>
</div>

11. You may have to use the following command to get this data.
import 'package:html/parser dart’;
output:
19.8,23,93%,south 2.2km/h
Method: 2
Since you access the HTML package, you can obtain the desired data by
accessing some HTML parsing and string processing whenever needed.
Here is the dart sample where you can utilize the parse data function in
your flutter application.

12. main.dart
import 'package:html/parser.dart' show parse;
main(List<string> args) {
parseData();
}
parseData(){
var document = parse("""
<div class="weather-item now">
<span class="time">Now</span>
<div class="temp">19.8<span>℃</span>
<small>(23℃)</small>
</div>
<table>
<tbody><tr>
<th><i class="icon01" aria-label="true"></i></th>
<td>93%</td>
</tr>
<tr>

13. <th><i class="icon02" aria-label="true"></i></th>
<td>south 2.2km/h</td>
</tr>
<tr>
<th><i class="icon03" aria-label="true"></i></th>
<td>-</td>
</tr>
</tbody></table>
</div>
""");

14. //declaring a list of String to hold all the data.
List<string> data = []
data.add(document.getElementsByClassName("time")[0].innerHtml);
//declaring a variable for temp since you use it in multiple places
var temp = document.getElementsByClassName("temp")[0];
data.add(temp.innerHtml.substring(0, temp.innerHtml.indexOf("<span>")));
data.add(temp.getElementsByTagName("small")[0].innerHtml.replaceAll(RegExp("[(|)|℃]"), ""));
//You can also do document.getElementsByTagName("td") but it is more specific here.
var rows = document.getElementsByTagName("table")[0].getElementsByTagName("td");
//Map element to its innerHtml,
because we're gonna need it.
//Iterate over the table-data and then store it safely in the data list
rows.map((e) => e.innerHtml).forEach((element) {
if(element != "-"){
data.add(element);
}
});
//print the data to console.
print(data);
}</span></string></string>

15. Output
How to parse HTML tags in Flutter
Do you need to parse HTML tags in your flutter project? Well! You can
follow the steps mentioned here to meet your needs instantly.
At first, you should create the flutter application.
Then, you must add the required plugins in pubspec.yaml file as
mentioned below.

16. dev_dependencies:
flutter_test:
sdk: Flutter
html: ^0.15.0
http: ^0.13.3
flutter_html: ^2.1.0
Now, you have to read the HTML file from the URL. Once you mention
the site, it reads the data online. Use the http:package to read the
data you have accessed and get the http class.
var response=await http.Client().get(Uri.parse(widget.url));
Now, you have HTML data fetched from the URL by accessing the
HTTP package. So, it is the right time to parse the fetched content.
You can use the below code to parse the HTML tags.

17. var chapters = document.getElementsByClassName("chapters");
chapters.forEach((element) {
var inner = element.innerHtml.toString();
if (inner.contains("href")) {
parse(inner).getElementsByTagName("li").forEach((element) {
var list = element.innerHtml;
if (list.contains("href")) {
//
indexlist_local.add(list.substring(list.indexOf("href=")+6,list.indexOf(">")-1));
indexlist_local.add(IndexContent(title: element.text,
path: list.substring(
list.indexOf("href=") + 6, list.indexOf(">") - 1)));
}
});
}
});
This code is written for fetching the data from the indexed tutorial
page “chapters.” According to the URL you choose, you can change
the index tag.
Finally, you can run the application successfully.

18. Conclusion
So, you will now be aware of the HTML parsing in Flutter for
android/iOS development. If you do not get the desired result even
after trying all the possible ways, you should seek professional
assistance. Hire Flutter developer to get assistance in HTML parsing and
complete your flutter project without hassle.
Source: https://flutteragency.com/html-parsing-flutter-android-ios-
development/