M3E Dismissible

A comprehensive Flutter package providing expressive, Material 3 card lists with dynamically rounded corners inside normal ListViews and CustomScrollViews (via slivers). It offers interactive dismissible cards featuring expressive M3 styling and spring physics.

It automatically calculates and draws the corners to fit exactly the Material 3 Expressive spec for adjacent items. It gives extensive customization options including customizable splash ripples, custom border colors, custom elevation and highly tunable haptic feedback along with stiffness and damping for animations.

---

🎮 Interactive Demo

You can try out the package demo here: m3e_core demo

---

🚀 Features

• Dynamic border radius: The first and last items get a larger outer radius while adjoining cards receive a smaller inner radius seamlessly.
• Reorderable Dismissible List (M3EReorderableDismissibleList): Combines spring-physics vertical drag reordering with horizontal swipe-to-dismiss and action reveal.
• Keyboard Navigation & Accessible Focus Rings: Full desktop & web keyboard support (Arrow keys, Space, Enter, Delete, Escape, Alt+Up/Down) with zero-layout-impact focus rings.
• Swipe Action Buttons: Expressive vertical pill action buttons (M3ESwipeAction) with staggered reveal animation, threshold haptics, dismiss-on-tap animation, and primary auto-execute.
• Pressed Scale Micro-interactions: Tactile squish feedback on touch/press down (pressedScale & pressedMotion).
• Modern InkSparkle Splash: Default InkSparkle splash effect matching modern Material 3 specifications.
• Direction Control: Configurable swipe direction (DismissDirection) — horizontal, left-only, right-only, or disabled.
• Accessibility Triggers: Single-tap, double-tap, or long-press to reveal hidden actions per Material 3 Accessibility Guidelines.
• Empty State Builder: emptyBuilder parameter on all list variants for empty-state widgets.
• Physics & Animations: Spring-driven physics for dragging. Neighbour-pull effects on swipe.
• Highly Customizable: Complete control over gaps, radii, colors, haptics, focus rings, and padding.
• Sliver & Column Support: Provides Slivers and Column wrappers out of the box to beautifully tie into complex layouts.

---

⚠️ Breaking Changes (v0.1.0)

• The neighbourStiffness and neighbourDamping properties have been removed and replaced with a single neighbourMotion property of type M3EMotion.
• Haptic properties (hapticOnTap and hapticOnThreshold) now accept the M3EHapticFeedback enum instead of integer constants for better type safety and clarity.

---

📦 Installation

Add m3e_dismissible and material_ui to your pubspec.yaml:

dependencies:
  material_ui: ^1.1.1
  m3e_dismissible: ^1.0.3

import 'package:material_ui/material_ui.dart';
import 'package:m3e_dismissible/m3e_dismissible.dart';

---

🧩 Components & Usage

M3E Dismissible Cards

Swipe-to-dismiss items with a beautiful spring-driven "neighbour pull" effect.

🔴 Dismissible M3E (Gmail Style)

🔴 Dismissible M3E (neighbourPull: 50.0, neighbourReach: 3, stiffness: 500, damping: 0.25, dismissThreshold: 0.6)

Usage:

M3EDismissibleCardList(
  itemCount: items.length,
  itemBuilder: (ctx, i) => Text(items[i].title),
  onDismiss: (i, dir) async { 
    items.removeAt(i); 
    return true; 
  },
  style: const M3EDismissibleCardStyle(
    outerRadius: 24,
    dismissThreshold: 0.3,
    neighbourPull: 12.0,
  ),
)

M3EDismissibleCardList Parameters:

Parameter	Type	Default	Description
itemCount	int	Required	Number of data items.
itemBuilder	IndexedWidgetBuilder	Required	Builds content for each item.
onDismiss	Future<bool> Function(int, DismissDirection)?	null	Called when swipe exceeds threshold. Return true to dismiss.
onTap	void Function(int)?	null	Called on tap (blocked during drag).
style	M3EDismissibleCardStyle	const M3EDismissibleCardStyle()	Visual and interaction configuration.
physics	ScrollPhysics?	null	Scroll physics override.
scrollController	ScrollController?	null	Scroll controller.
listPadding	EdgeInsetsGeometry?	null	Padding around the entire list.
shrinkWrap	bool	false	Whether the list should shrink-wrap its children.
clipBehavior	Clip	Clip.hardEdge	Clip behavior for the list.

M3EDismissibleCardStyle Parameters:

Parameter	Type	Default	Description
outerRadius	double	18.0	Outer corner radius for first/last/single items.
innerRadius	double	4.0	Inner corner radius for middle items.
selectedBorderRadius	double?	null	Radius applied to the dragged card once threshold is crossed.
backgroundBorderRadius	double?	100	Radius applied to the background when swiping start-to-end.
secondaryBackgroundBorderRadius	double?	100	Radius applied to the secondary background when swiping end-to-start.
collapseSpeed	double	50	Speed of collapse animation after the card is dismissed. Higher Number = Faster Collapse, Lower Number = Slower Collapse
gap	double	3.0	Vertical gap between cards.
color	Color?	surfaceContainer	Card background colour.
padding	EdgeInsetsGeometry?	null	Inner padding of each card's content area.
margin	EdgeInsetsGeometry?	null	Outer margin around each card.
border	BorderSide?	null	Optional border drawn on every card.
elevation	double	0.0	Resting elevation.
boxShadow	List<BoxShadow>?	null	Custom shadow override. Set to empty list [] to remove shadow completely.
pressedScale	double?	null	Scale factor applied when card is pressed down (e.g. 0.97 for tactile squish).
pressedMotion	M3EMotion	expressiveSpatialFast	Spring motion for press-down and release scale animation.
focusRingColor	Color?	null	Custom focus ring color for keyboard navigation.
focusRingGap	double	0.0	Gap between card edge and focus ring.
focusRingWidth	double	2.0	Stroke width of the focus ring.
background	Widget?	null	Revealed background when swiping start-to-end.
secondaryBackground	Widget?	null	Revealed background when swiping end-to-start.
splashColor	Color?	null	Ink splash color.
highlightColor	Color?	null	Ink highlight color.
splashFactory	InteractiveInkFeatureFactory?	InkSparkle.splashFactory	Splash factory (InkSparkle by default).
enableFeedback	bool	true	Whether gestures provide acoustic/haptic feedback.
hapticOnTap	M3EHapticFeedback	none	Haptic feedback intensity on tap.
dismissThreshold	double	0.2	Fraction of width before dismiss triggers.
hapticOnThreshold	M3EHapticFeedback	light	Haptic feedback level when crossing dismiss or action reveal threshold.
dismissHapticStream	bool	false	Fire continuous light haptics during drag.
neighbourPull	double	8.0	Maximum pixel offset applied to neighbouring cards.
neighbourReach	int	3	How many cards above + below the dragged card are affected.
neighbourMotion	M3EMotion	800/0.7	Spring motion for neighbour snapping.
snapBackMotion	M3EMotion	380/0.6	Motion for snapping back when drag is released below threshold.
flyMotion	M3EMotion	400/0.8	Motion for flying off screen when drag is released above threshold.
direction	DismissDirection	horizontal	Allowed swipe directions. Use none to disable swipe gestures.
actions	List<M3ESwipeAction>?	null	Action buttons revealed when swiping start-to-end (right in LTR).
secondaryActions	List<M3ESwipeAction>?	null	Action buttons revealed when swiping end-to-start (left in LTR).
actionSpacing	double	8.0	Spacing between revealed action buttons.
autoExecutePrimaryOnFullSwipe	bool	true	Auto-trigger primary action when swiping past threshold.
actionRevealTrigger	M3EActionRevealTrigger	none	Single-point interaction to reveal actions (tap, doubleTap, longPress).
emptyBuilder	WidgetBuilder?	null	Builder for empty-state widget when there are no items.

Variants Available: M3EReorderableDismissibleList, SliverM3EDismissibleCardList, M3EDismissibleCardColumn

---

🔄 Reorderable Dismissible List (M3EReorderableDismissibleList)

A unified Material 3 Expressive list component that seamlessly combines spring-physics vertical drag reordering (dynamic placeholder slot, bouncy spring neighbor displacement) with horizontal swipe-to-dismiss and action reveal.

M3EReorderableDismissibleList(
  itemCount: items.length,
  keyBuilder: (index) => ValueKey(items[index].id),
  onReorder: (oldIndex, newIndex) {
    setState(() {
      if (newIndex > oldIndex) newIndex--;
      final item = items.removeAt(oldIndex);
      items.insert(newIndex, item);
    });
  },
  onDismiss: (index, direction) async {
    setState(() => items.removeAt(index));
    return true;
  },
  style: const M3EDismissibleCardStyle(
    outerRadius: 20.0,
    innerRadius: 4.0,
    pressedScale: 0.97,
    actions: [
      M3ESwipeAction(
        icon: Icon(Icons.archive),
        label: Text('Archive'),
      ),
    ],
  ),
  itemBuilder: (context, index) {
    return ListTile(
      title: Text(items[index].title),
      trailing: const Icon(Icons.drag_handle),
    );
  },
)

---

⌨️ Keyboard Navigation & Accessibility

m3e_dismissible provides comprehensive keyboard navigation and zero-layout-impact focus rings out of the box:

Shortcut	Action
Tab / Shift + Tab	Focus next / previous card or action button.
ArrowLeft / ArrowRight	Reveal leading / trailing swipe action buttons on focused card.
ArrowLeft / ArrowRight (in action drawer)	Navigate focus between individual action buttons.
Space / Enter	Trigger focused action button or tap card.
Escape	Close revealed action drawer and return focus to the card.
Delete / Backspace	Dismiss the focused card (or open actions if actions configured).
Alt + ArrowDown / Alt + ArrowUp	Reorder item forward / backward in M3EReorderableDismissibleList.

---

🏗️ Motion System (M3EMotion)

Spring physics presets for animations. All presets use specific stiffness and damping values to achieve their respective feels.

🏗️ Spatial Presets (Shape Morphing)

Used for animating the container shape and border radius.

Preset Name	Stiffness	Damping	Description
standardSpatialFast	1400	0.9	Snappy spring for responsive feel.
standardSpatialDefault	700	0.9	Balanced spring for general use.
standardSpatialSlow	300	0.9	Relaxed spring for dramatic feel.
aospSpatial	380	1.0	Matches AOSP's notification list feel (no bounce).
expressiveSpatialFast	800	0.6	Bouncier spring for expressive feel.
expressiveSpatialDefault	380	0.75	Bouncy, balanced spring for expressive feel.
expressiveSpatialSlow	200	0.8	Very bouncy spring for dramatic expressive feel.

✨ Effects Presets (Opacity/Scale)

Used for internal content animations like cross-fades.

Preset Name	Stiffness	Damping	Description
standardEffectsFast	3800	1.0	Snappy effect animation.
standardEffectsDefault	1600	1.0	Balanced effect animation.
standardEffectsSlow	800	1.0	Relaxed effect animation.
expressiveEffectsFast	3800	1.0	Snappy expressive effect.
expressiveEffectsDefault	1600	1.0	Balanced expressive effect.
expressiveEffectsSlow	800	1.0	Relaxed expressive effect.

🛠️ Custom Motion

Create a custom spring with specific physics:

M3EMotion.custom(stiffness: 380, damping: 0.75, snapToEnd: false)

---

M3ESwipeAction

Expressive vertical pill action buttons revealed when swiping a card.

Parameter	Type	Default	Description
icon	Widget	Required	The icon widget representing this action.
label	Widget?	null	Optional label text displayed below the icon.
backgroundColor	Color?	secondaryContainer / primary	Background color for the action button.
foregroundColor	Color?	onSecondaryContainer / onPrimary	Foreground color (icon & label).
onTap	VoidCallback?	null	Callback when this action is tapped or triggered by full swipe.
isPrimary	bool	false	Whether this is the primary end-aligned action (auto-fired on full swipe).
dismissOnTap	bool	false	Whether tapping this action animates card dismissal (fly-out and collapse) before calling onTap.
width	double	52.0	Width of the vertical pill button.
height	double?	null	Explicit height (inherits card slot height if null).
borderRadius	BorderRadiusGeometry?	BorderRadius.circular(100)	Custom border radius.
haptic	M3EHapticFeedback	medium	Haptic feedback when tapped.

M3EDismissibleCardList(
  style: M3EDismissibleCardStyle(
    actions: [
      M3ESwipeAction(
        icon: const Icon(Icons.archive_rounded),
        label: const Text('Archive'),
        backgroundColor: Colors.teal,
        foregroundColor: Colors.white,
        onTap: () => print('Archived!'),
      ),
      M3ESwipeAction(
        icon: const Icon(Icons.delete_rounded),
        label: const Text('Delete'),
        isPrimary: true,
        dismissOnTap: true,
        onTap: () => print('Deleted!'),
      ),
    ],
    secondaryActions: [
      M3ESwipeAction(
        icon: const Icon(Icons.reply_rounded),
        label: const Text('Reply'),
      ),
    ],
  ),
  ...
)

🎯 Check the Example App for more details.

---

🐞 Found a bug? or ✨ You have a Feature Request?

Feel free to open a Issue or Contribute to the project.

Hope You Love It!

---

Credits

• Motor Pub Package for Expressive Animations
• Claude and Gemini for helping me with the code and documentation.

Radhe Radhe 🙏