flutter_widget_from_html 0.5.0-rc.2020071301

Flutter package for widget tree building from html that supports hyperlink, image, nested list, etc.

Flutter Widget from HTML #

CirrusCI codecov Pub

A Flutter package for building Flutter widget tree from HTML with support for IFRAME, VIDEO and many other tags.

This package extends the flutter_widget_from_html_core package with extra functionalities by using external depedencies like cached_network_image or url_launcher. It should be good enough as a quick starting point but you can always use the core directly if you dislike the dependencies.

Usage #

To use this package, add flutter_widget_from_html as a dependency in your pubspec.yaml file.

See the Example app for inspiration.

Example #

const kHtml = '''
<h1>Heading</h1>
<p>A paragraph with <strong>strong</strong> <em>emphasized</em> text.</p>
<ol>
  <li>List item number one</li>
  <li>
    Two
    <ul>
      <li>2.1 (nested)</li>
      <li>2.2</li>
    </ul>
  </li>
  <li>Three</li>
</ol>
<p>And YouTube video!</p>
<iframe src="https://www.youtube.com/embed/jNQXAC9IVRw" width="560" height="315"></iframe>
''';

class HelloWorldScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) => Scaffold(
        appBar: AppBar(
          title: Text('HelloWorldScreen'),
        ),
        body: Padding(
          padding: const EdgeInsets.all(8.0),
          child: HtmlWidget(
            kHtml,
            webView: true,
          ),
        ),
      );
}

void main() => runApp(MaterialApp(home: HelloWorldScreen()));

Features #

HTML tags #

Below tags are the ones that have special meaning / styling, all other tags will be parsed as text.

  • A: underline, theme accent color, launch url via url_launcher, support base url resolver.
  • H1/H2/H3/H4/H5/H6
  • IFRAME via WebView. Available configurations:
    • .webView, default=false
    • .webViewJs, default=true
    • .webViewPadding
    • To render IFRAME as web view: set webView=true in config and setup iOS project manually.
    • If the IFRAME has no width and height attributes, the web view will be rendered initially in a 16:9 box and automatically resize itself afterwards.
  • IMG with support for asset (asset://), data uri and network image via CachedNetworkImage. Additional .svg file support via flutter_svg.
  • LI/OL/UL with support for:
    • Attributes: type, start, reversed
    • Inline style list-style-type values: lower-alpha, upper-alpha, lower-latin, upper-latin, circle, decimal, disc, lower-roman, upper-roman, square
  • TABLE/CAPTION/THEAD/TBODY/TFOOT/TR/TD/TH with support for:
    • TABLE attributes (border, cellpadding) and inline style (border)
    • TD/TH attributes colspan, rowspan via flutter_layout_grid
  • SVG via flutter_svg
  • VIDEO via chewie
  • ABBR, ACRONYM, ADDRESS, ARTICLE, ASIDE, B, BIG, BLOCKQUOTE, BR, CENTER, CITE, CODE, DD, DEL, DFN, DIV, DL, DT, EM, FIGCAPTION, FIGURE, FONT, FOOTER, HEADER, HR, I, INS, KBD, MAIN, NAV, P, PRE, Q, RP, RT, RUBY, S, SAMP, SECTION, STRIKE, STRONG, SUB, SUP, TT, U, VAR

These tags and their contents will be ignored:

  • SCRIPT
  • STYLE

Attributes #

  • dir: auto, ltr and rtl

Inline stylings #

  • border-top, border-bottom: overline/underline with support for dashed/dotted/double/solid style
  • color: hex values, rgb(), hsl() or named colors
  • direction (similar to dir attribute)
  • font-family
  • font-size: absolute (e.g. xx-large), relative (larger, smaller) and values (in em, % and px)
  • font-style: italic/normal
  • font-weight: bold/normal/100..900
  • line-height: number, values (in em, % and px) or normal
  • margin and margin-xxx (values in px, em)
  • padding and padding-xxx (values in px, em)
  • vertical-align: baseline/top/bottom/middle/sub/super
  • text-align: center/justify/left/right
  • text-decoration: line-through/none/overline/underline
  • text-overflow: clip/ellipsis. Note: text-overflow: ellipsis should be used in conjuntion with max-lines or -webkit-line-clamp for better result.
  • Sizing (width & height, max-xxx, min-xxx) with values in px, em

Extensibility #

See flutter_widget_from_html_core for details.