The Html widget had two issues in the Container widget with the maxWidth property.

[gzlock]

flutter_html version: 0.11.1

flutter doctor:

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, v1.12.13+hotfix.7, on Mac OS X 10.15.3 19D76, locale zh-Hans-CN)
 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
[✓] Xcode - develop for iOS and macOS (Xcode 11.3.1)
[✓] Android Studio (version 3.5)
[!] IntelliJ IDEA Ultimate Edition (version 2019.3.1)
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
[✓] Connected device (2 available)

Code:

/// The message contents
/// First message data: 'short message'
/// Second message data: 'message include images, line 1'
///            '<img src="http://via.placeholder.com/350x350/d89cf6">'
///            '<div>line 2</div>'
///            '<img src="http://via.placeholder.com/350x350/d89cf6">'
/// Third message data: 'multiple lines<br/>line 1\nline 2'
final screen = MediaQuery.of(context).size;
Container(
      padding: EdgeInsets.only(left: 5, right: 5, top: 8, bottom: 8),
      constraints: BoxConstraints(maxWidth: screen.width * 0.6),
      decoration: BoxDecoration(
        color: Color.blue,
      ),
      child: Html(
        imageProperties: ImageProperties(
          width: 200,
          fit: BoxFit.fitWidth,
        ),
        data: message.message,
        useRichText: true,
        shrinkToFit: true,
        defaultTextStyle: TextStyle(color: Colors.white),
        renderNewlines: true,
        customTextAlign: (e) => TextAlign.left,
      ),
    );

The first issue:

When the 'useRichText' and 'shrinkToFit' properties both set true,

The "line 2" is centered even if I set customTextAlign: (e) => TextAlign.left

How to set the column(belongs to the HtmlRichTextParser) crossAxisAlignment to CrossAxisAlignment.start?

---

The second issue:

When I set the 'useRichText' property to false, the 'line 2' was align to left, well done.

But the multiple line bubble was filled with max width.

It looks like the 'shrinkToFit' property is invalid.

[Sub6Resources]

Try using version 1.0.0-pre.1.

[Sub6Resources]

Closing, since this appears to have fixed your issue. Let me know if you continue to have issues!