EzListView #

A defensive, self-aware drop-in replacement for Flutter's ListView that automatically prevents layout crashes from unbounded constraints in Column, Row, Flex, and nested scroll views.

🛑 The Problem #

In Flutter, placing a ListView inside an unbounded parent immediately throws a fatal runtime exception:

• "Vertical viewport was given unbounded height"
• "Horizontal viewport was given unbounded width"

Common culprits include:

• Vertical ListView inside a Column or Flex without Expanded or Flexible
• Horizontal ListView inside a Row
• Nesting a ListView directly inside another scroll view (CustomScrollView, SingleChildScrollView) without shrinkWrap: true or explicit height
• Unconstrained widgets like Card or non-expanded Stack children

Instead of a helpful warning, the entire widget subtree fails to render, showing the red error screen.

✅ The EzListView Solution #

EzListView intercepts unbounded constraints before Flutter's viewport layout throws an exception:

• Crash Prevention: Detects unbounded dimensions along the scroll or cross axis and applies safe, responsive fallback dimensions.
• Developer Feedback:
  • Debug Mode: Displays a red border around the fallback container and reports a structured FlutterError pointing out the exact parent culprit (e.g. Column, Row) with actionable fix instructions.
  • Release Mode: Silently applies the fallback layout so your users never experience a crash or red screen.
• 100% Drop-in Parity: Supports all four standard ListView constructors:
  • EzListView(...) (children list)
  • EzListView.builder(...)
  • EzListView.separated(...)
  • EzListView.custom(...)

📦 Installation #

flutter pub add ez_list_view

🚀 Usage #

1. Drop-in Replacement inside a Column #

Instead of crashing, EzListView safely displays your items and shows a red debug outline with console diagnostics:

Column(
  children: [
    const Text('Header'),
    // In standard Flutter, ListView.builder crashes here.
    // EzListView prevents the crash gracefully!
    EzListView.builder(
      itemCount: 20,
      itemBuilder: (context, index) => ListTile(
        title: Text('Item $index'),
      ),
    ),
  ],
)

2. Default Children Constructor #

EzListView(
  children: const [
    ListTile(title: Text('Profile')),
    ListTile(title: Text('Settings')),
    ListTile(title: Text('Logout')),
  ],
)

3. Separated Constructor #

EzListView.separated(
  itemCount: 10,
  itemBuilder: (context, index) => ListTile(title: Text('Message $index')),
  separatorBuilder: (context, index) => const Divider(),
)

4. Custom Fallback Dimensions & Telemetry #

EzListView.builder(
  itemCount: 25,
  itemBuilder: (context, index) => Text('Row $index'),
  fallbackHeight: 300, // Custom height when unbounded
  showDebugIndicator: false, // Hide the red border in debug mode
  onUnboundedDetected: ({
    required bool isWidthUnbounded,
    required bool isHeightUnbounded,
    required String? culprit,
  }) {
    // Send telemetry or log to your analytics service
    print('Unbounded layout caught in $culprit: width=$isWidthUnbounded, height=$isHeightUnbounded');
  },
)

💡 The Permanent Fix #

While EzListView prevents application crashes and provides graceful fallbacks, best practice in Flutter is to explicitly constrain scrollables. When EzListView flags an issue in debug mode, apply one of the following permanent fixes:

// Option A: Wrap in Expanded or Flexible inside Column/Row
Column(
  children: [
    Expanded(
      child: EzListView.builder(...),
    ),
  ],
)

// Option B: Set explicit dimensions
SizedBox(
  height: 300,
  child: EzListView.builder(...),
)

// Option C: Use shrinkWrap if the list has a small, finite number of children
EzListView.builder(
  shrinkWrap: true,
  physics: const NeverScrollableScrollPhysics(),
  ...
)

🤝 Contributing #

Contributions, issues, and feature suggestions are always welcome! Check out the GitHub repository.

📜 License #

MIT License - see LICENSE for details.