如何在Flutter文本小部件中显示HTML字符串

Question

如何在Flutter文本小部件中显示HTML字符串

53

如何在Flutter中显示HTML标签字符串，我已经尝试了一个插件，但它不起作用。

new HtmlView(
     data: html,
     baseURL: "", // optional, type String
     onLaunchFail: (url) { // optional, type Function
     print("launch $url failed");
   }

这是我的HTML代码。

“Follow<a class='sup'><sup>pl</sup></a> what was sent down to you from your Lord, and do not follow other guardians apart from Him. Little do <span class='h'>you remind yourselves</span><a class='f'><sup f=2437>1</sup></a>.”

我使用了 flutter_html_view: "^0.5.10" 这个插件。

- Deepak Gehlot

你能发布Flutter版本吗？ - Nagendra Badiganti

@NagendraBadiganti Flutter（beta频道，v1.0.0，在Mac OS X 10.13.6 17G65上，本地化为en-IN） - Deepak Gehlot

使用 flutter_html: ^0.8.2 依赖库进行检查，一直以来都很好用。我刚刚发布了一个答案。如果它有效，请点赞。 - Nagendra Badiganti

这个插件无法很好地渲染你的HTML代码。请阅读文档 该插件不支持完整的HTML代码渲染。 - shadowsheep

Flutter团队的webview_flutter插件对我来说运行得非常好：https://dev59.com/3FQJ5IYBdhLWcg3wdVgW#55149298 - Suragch

我认为这个插件已经消失了。 - Elia Weiss

10个回答

13

我刚刚完成了以下步骤，它很好用。

将flutter_html添加到您的pubspec.yaml文件中。

dependencies:
  flutter:
    sdk: flutter
  flutter_html: ^0.8.2

运行以下命令更新软件包。

flutter pub get

导入flutter_html。

import 'package:flutter_html/flutter_html.dart';

使用Html小部件替换Text小部件。

   child: 
   // Text(
   //   "Hello Programmer",
   //   style: TextStyle(fontSize: 18),
   // ),
   Html(data:"<p>Hello <b>Flutter</b><p>"),

- Furkan Öztürk

如果HTML中有视频或图像链接怎么办？ - Jaimin Modi

5

请勿使用flutter_html_view，请参阅文档：

支持的标签

p

em

b

img

video

h1,

h2,

h3,

h4,

h5,

h6

注意

该插件将一些html标记转换为flutter小部件。此插件不支持呈现完整的html代码（flutter中没有内置的Web呈现支持）。

因为它不能呈现完整的html代码，所以它无法很好地呈现您的html。

但是，您可以尝试其他插件，如flutter_html

https://github.com/Sub6Resources/flutter_html

并尝试看看它们是否表现更好。

更新

在pubspec.yaml中我添加了：

dependencies:
  flutter_html: ^0.8.2

我的main.dart文件如下：

import 'package:flutter/material.dart';
import 'package:flutter_html/flutter_html.dart';


void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  var html = "Follow<a class='sup'>pl</a> what was sent down to you from your Lord, and do not follow other guardians apart from Him. Little do <p class='h'>you remind yourselves</p><a class='f'><sup f=2437>1</a>.";


  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Html(
              data: html,
              ),
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

- shadowsheep

你能给我展示一下你的代码吗？我已经检查过了，但是我的 PL 显示不像你的。 - Deepak Gehlot

@DeepakGehlot 当然可以。我已经更新了我的答案。我刚刚修改了标准的Flutter Activity项目来进行测试。 - shadowsheep

2

其他回答提到的所有软件包都不再维护（至少在我写这篇答案时是这样），它们会与我使用的其他最近更新的软件包发生冲突，因此我最终选择了使用此软件包：flutter_widget_from_html（注：这不是我的软件包）。

- Alexa289

我正在使用flutter_html: ^2.2.1，在Android和iOS上运行良好...但在SDK版本方面给了我一些问题。 - E. Greeff

2

请将以下内容添加到您的pubspec.yaml文件中：

dependencies:
  flutter_html:

目前支持的HTML标签：

a、abbr、acronym、address、article、aside、b、bdi、bdo、big、blockquote、body、br、caption、cite、code、data、dd、del、dfn、div、dl、dt、em、figcaption、figure、footer、h1、h2、h3、h4、h5、h6、header、hr、i、img、ins、kbd、li、main、mark、nav、noscript、ol、p、pre、q、rp、rt、ruby、s、samp、section、small、span、strike、strong、sub、sup、table、tbody、td、template、tfoot、th、thead、time、tr、tt、u、ul、var

示例用法：

Column(
   mainAxisAlignment: MainAxisAlignment.start,
   crossAxisAlignment: CrossAxisAlignment.start,
   children: [
      new Html(
         data: "<b>Welcome</b>,
          defaultTextStyle: TextStyle(fontSize: 15),
       ),
     ],
)

- Techalgoware

1

可能有点晚了，但我已经做了一个接受和标签的项目。

这样你就可以这样做：

HTMLText('<b><i>SOME VERY IMPORTANT TEXT</i></b>');

它可以将您的HTML转换为基于Flutter的小部件，并且还会尊重深色/浅色主题颜色。

https://github.com/forumics/flutter-html-text

- Gabriel TOH KaWei

1

在 pubspec.yml 文件中添加以下内容：

dependencies:
  flutter_html:

然后运行：

flutter clean && flutter pub get

最后，添加以下代码：

import 'package:flutter_html/flutter_html.dart';
.
.
.
body: Center( Html(
      data: """
            <div>This is the start of a div
              <a class='sup'><sup>a sup</sup></a> 
              and after sub
              <b>Bold</b>
              <h1>This is a header with number 1557</h1> 
              A text and 
            <span class='h'>some stuff</div>
            """,
    ),)

到目前为止，它在移动端和Web端都能够正常工作。

- Mostafa Wael

如果HTML中有视频或图像链接怎么办？ - Jaimin Modi

1

我之前尝试过使用图片，效果很好。虽然我没有尝试过视频，但我认为也应该没问题。请在尝试后与我们分享您的经验。 - Mostafa Wael

1

使用flutter_webview_plugin插件

示例:

new WebviewScaffold(
              url: new Uri.dataFromString('<html><body>hello world</body></html>', mimeType: 'text/html').toString()

在自定义矩形内部的Webview。

final flutterWebviewPlugin = new FlutterWebviewPlugin();

flutterWebviewPlugin.launch(url,
  fullScreen: false,
  rect: new Rect.fromLTWH(
    0.0,
    0.0,
    MediaQuery.of(context).size.width,
    300.0,
  ),
);

- Shyju M

你有检查示例代码吗？https://github.com/fluttercommunity/flutter_webview_plugin/blob/master/example/lib/main.dart - Shyju M

是的，我有 :-）。这就是我提出问题的原因。警告：WebView没有集成在小部件树中，它是一个覆盖在Flutter视图之上的本地视图。您将无法使用snackbars、dialogs等。示例代码将其用作页面而不是小部件树中的组件。 - shadowsheep

创建自己的脚手架并在矩形内呈现Web视图，然后您可以使用Snackbar、Dialog等。 - Shyju M

很高兴知道，谢谢。但我想那已经超出了OP的问题范围。你不认为这会需要太多代码才能得到他所要求的吗？ - shadowsheep

无法使用此插件加载此HTML，我已经使用WebviewScaffold进行测试，但它无法加载，显示错误“字符串包含无效字符。”<html><body>跟随<a class='sup'><sup>pl</sup></a>你的主所降示的，并不要追随除祂以外的守护者。你们很少自我提醒<a class='f'><sup f=2437>1</sup></a>。</body></html> - Deepak Gehlot

显示剩余5条评论

0

要将HTML转换为TextWidget，您可以使用html包。以下是一个示例：

首先添加依赖项

dependencies:
  flutter:
    sdk: flutter
  html: ^0.15.0
  url_launcher: ^6.1.10

然后导入包并使用解析方法将HTML字符串转换为文档对象：

import 'package:flutter/material.dart';
import 'package:html/parser.dart' show parse;
import 'package:html/dom.dart' as dom;
import 'package:url_launcher/url_launcher.dart';

class HtmlToRichTextWidget extends StatelessWidget {
  final String? htmlString;

  const HtmlToRichTextWidget({Key? key, this.htmlString = ''})
      : super(key: key);

  @override
  Widget build(BuildContext context) {
    final document = html_parser.parse(htmlString);
    final inlineSpans = _parseNode(document.body!);

    return RichText(
      text: TextSpan(
          children: inlineSpans, style: const TextStyle(color: Colors.black)),
    );
  }

  List<InlineSpan> _parseNode(dom.Node node) {
    final inlineSpans = <InlineSpan>[];

    if (node.nodeType == dom.Node.TEXT_NODE) {
      final text = node.text;
      inlineSpans.add(TextSpan(text: text));
    } else if (node.nodeType == dom.Node.ELEMENT_NODE) {
      final element = node as dom.Element;

      switch (element.localName) {
        case "b":
        case 'strong':
          return _parseElements(
              element, const TextStyle(fontWeight: FontWeight.bold));
        case "i":
        case 'em':
          return _parseElements(
              element, const TextStyle(fontStyle: FontStyle.italic));
        case "u":
          return _parseElements(
              element, const TextStyle(decoration: TextDecoration.underline));
        case "sub":
          inlineSpans.add(WidgetSpan(
            alignment: PlaceholderAlignment.bottom,
            child: SizedBox(
              height: 10,
              child: Text(
                element.text,
                style: const TextStyle(
                  fontSize: 12,
                  color: Colors.blue,
                  textBaseline: TextBaseline.alphabetic,
                ),
              ),
            ),
          ));
          break;
        case "sup":
          inlineSpans.add(WidgetSpan(
            alignment: PlaceholderAlignment.top,
            child: SizedBox(
              height: 10,
              child: Text(
                element.text,
                style: const TextStyle(
                  fontSize: 12,
                  color: Colors.blue,
                  textBaseline: TextBaseline.alphabetic,
                ),
              ),
            ),
          ));
          break;
        case "p":
          return _parseElements(element, const TextStyle());
        case "span":
          // print(element.className);
          return _parseElements(element, const TextStyle(color: Colors.red));

        case "a":
          final href = element.attributes['href'] ?? '';
          return _parseElements(
              element,
              const TextStyle(
                  decoration: TextDecoration.underline, color: Colors.blue),
              href);
        case 'br':
          inlineSpans.add(const TextSpan(text: "\n"));
          break;
        default:
          return _parseElements(element, const TextStyle());
      }
    }

    return inlineSpans;
  }

  List<InlineSpan> _parseElements(dom.Element element, TextStyle style,
      [String? href]) {
    final spans = <InlineSpan>[];

    for (final node in element.nodes) {
      final childTextSpans = _parseNode(node);

      for (final childTextSpan in childTextSpans) {
        var launch = TapGestureRecognizer()
          ..onTap = () => launchUrl(Uri.tryParse(href ?? "")!);
        if (childTextSpan is TextSpan) {
          spans.add(
            TextSpan(
              text: childTextSpan.text,
              style: style.merge(childTextSpan.style),
              recognizer: href != null ? launch : null,
            ),
          );
        } else {
          spans.add(childTextSpan);
          print(childTextSpan.toString());
        }
      }
    }
    return spans;
  }
}

在更新的版本中，我们在_parseNode方法中添加了对switch语句标签的支持。我们还更新了_parseElements方法，以接受可选的href参数，当遇到标签时，我们使用它来创建TapGestureRecognizer并添加到TextSpan中。

您需要从url_launcher包中导入package:flutter/gestures.dart和package:url_launcher/url_launcher.dart，以使用TapGestureRecognizer和launch函数。

- Abhishek Yadav

-1

如果你有一个对象列表并且需要进行groupBy操作，可以使用以下链接： groupBy_in_flutter

- Azade Rahmati

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Nagendra Badiganti · Accepted Answer

这个插件没有问题，我只是用你的HTML创建了一个示例，并且它工作正常。尝试使用下面的代码片段替换，看看是否有效。

这个插件没问题，我只是用你提供的 HTML 创建了一个样本，它可以正常工作。尝试使用下面的代码片段进行替换，看看是否能解决问题。

dependencies:
  flutter_html: ^0.8.2

并导入代码以渲染HTML

import 'package:flutter_html/flutter_html.dart';
import 'package:html/dom.dart' as dom;


 body: new Center(
            child: SingleChildScrollView(
              child: Html(
                data: """
                <div>Follow<a class='sup'><sup>pl</sup></a> 
                  Below hr
                    <b>Bold</b>
                <h1>what was sent down to you from your Lord</h1>, 
                and do not follow other guardians apart from Him. Little do 
                <span class='h'>you remind yourselves</span><a class='f'><sup f=2437>1</sup></a></div>
                """,
                padding: EdgeInsets.all(8.0),
                onLinkTap: (url) {
                  print("Opening $url...");
                },
                customRender: (node, children) {
                  if (node is dom.Element) {
                    switch (node.localName) {
                      case "custom_tag": // using this, you can handle custom tags in your HTML 
                        return Column(children: children);
                    }
                  }
                },
              ),
            ),
          )