elva_scroll_view 0.0.4

A Flutter package for nested scrolling with coordinated scrolling and inertial scrolling transfer capabilities.

Elva Scroll View

A Flutter package for nested scrolling with coordinated scrolling and inertial scrolling transfer capabilities.

Documentation: https://github.com/Y2Yi/toy

Features

• Nested Scrolling Support: Supports multi-level nested scroll views with smooth scrolling coordination
• Inertial Scrolling Transfer: Inertial scrolling animations can be transferred across multiple scroll components
• Shell Mode: Supports preventing scroll offset from continuing to propagate upward, enabling independent scroll areas
• Flexible Builder Pattern: Uses the Builder pattern for easy integration into existing code
• Custom Notification System: Provides rich scroll event notifications

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  elva_scroll_view:
    path: ./elva_scroll_view

Or if published to pub.dev:

dependencies:
  elva_scroll_view: ^0.1.0

Usage

Basic Usage

ElvaScrollViewBuilder(
  builder: (context, controller) {
    return CustomScrollView(
      controller: controller,
      slivers: [
        SliverAppBar(...),
        SliverList(...),
      ],
    );
  }
)

Nested Scrolling

ElvaScrollViewBuilder(
  debugLabel: "parent",
  builder: (context, parentController) {
    return CustomScrollView(
      controller: parentController,
      slivers: [
        SliverAppBar(...),
        SliverFillRemaining(
          child: Row(
            children: [
              Expanded(
                child: ElvaScrollViewBuilder(
                  debugLabel: "child_1",
                  builder: (context, childController) {
                    return CustomScrollView(
                      controller: childController,
                      slivers: [...]
                    );
                  }
                )
              ),
              Expanded(
                child: ElvaScrollViewBuilder(
                  debugLabel: "child_2",
                  builder: (context, childController) {
                    return CustomScrollView(
                      controller: childController,
                      slivers: [...]
                    );
                  }
                )
              ),
            ],
          ),
        ),
      ],
    );
  }
)

Shell Mode

ElvaScrollViewBuilder(
  isShell: true,
  builder: (context, controller) {
    return CustomScrollView(
      controller: controller,
      slivers: [...]
    );
  }
)

Core Components

ElvaScrollViewBuilder

The main builder component for wrapping CustomScrollView that needs coordinated scrolling.

Parameters:

• builder: Builder function that receives context and controller
• debugLabel: Debug label for logging purposes
• isShell: Whether it's a shell component. When true, scroll offset won't continue to propagate upward

ElvaScrollViewScrollController

Custom scroll controller that implements TransportPixelNode mixin, responsible for handling scroll coordination and transfer.

ElvaScrollViewPosition

Custom scroll position manager that extends Flutter's native ScrollPositionWithSingleContext, implementing:

• User drag offset handling
• Inertial scrolling startup and management
• Animation offset application

ElvaScrollViewAnimationOverscrollDispatcher

Inertial scrolling animation dispatcher, responsible for:

• Collecting components that need to accept scroll events
• Dispatching inertial scrolling animations in order
• Managing overscroll transfer

Notifications

ElvaScrollViewAnimationScrollingNotification

Dispatched when global overscroll event animation occurs.

Properties:

• overscroll: The overscroll amount
• consumed: The amount consumed by current scroll view

Example

See the example directory for a complete example application.

License

MIT