Expansion Tile List

The ExpansionTileList serves as a container for the ExpansionTile widget, enabling the creation of a list of tiles. It offers additional features that allow you to customize the appearance of the tiles and control their expansion programmatically.

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Description

The expansion_tile_list package offers a highly customizable list of expansion tiles for Flutter applications. It enables developers to create expandable tile lists with extensive options for appearance, animations, and control over the expansion behaviour. The package includes features such as a global trailing widget, trailing animation, and various expansion modes to accommodate different use cases.

Basic Usage Trailing Controller Expansion Mode

Features

  • Compatible with ExpansionTile widgets.
  • Includes additional features when using ExpansionTileItem widget instead of ExpansionTile
  • Supports hot reload.🔥
  • Accordion like expansion mode and many more.
  • Customizable trailing widget and trailing animation.
  • Customize the appearance of the tiles using tileBuilder, separatorBuilder and tileGapSize.
  • Programmatically control the expansion of the tiles with ExpansionTileListController.
  • Listen to the expansion changes of the tiles.
  • Checkout the Demo to explore the latest features and experience the features firsthand!

List Features

All the features affects all the tiles in the ExpansionTileList.

  • tileGapSize allows you to specify the size of the gap between each tile in the ExpansionTileList.
  • trailing allows you to specify the trailing widget for all tiles, can be overridden byExpansionTile trailing property.
  • trailingAnimation allows you to specify a custom animation for the trailing widget.
  • enableTrailingAnimation allows you to enable or disable the trailing animation.
  • tileBuilder allows the customization of the creation and appearance of the tiles in the ExpansionTileList.
  • separatorBuilder allows the customization of the creation and appearance of the separators between the tiles in the ExpansionTileList.
  • initialExpandedIndexes allows you to specify the indexes of the tiles that are initially expanded.
  • controller allows you to programmatically control the expansion of the tiles.
  • onExpansionChanged allows you to listen to the expansion changes of the tiles.
  • new ExpansionMode allows you to specify the expansion mode of the ExpansionTileList. This feature can be used only with named constructor.
    • ExpansionMode.atMostOne allows you to expand at most one tile at a time. (i.e. zero or one )
    • ExpansionMode.atLeastOne ensures that at least one tile is always expanded (i.e. one or more )
    • ExpansionMode.exactlyOne allows you to expand exactly one tile at a time. (i.e. one )
    • ExpansionMode.any allows you to expand any number of tiles. (i.e. zero or more )

Item Features

By default ExpansionTileList supports ExpansionTile widget as children to create tiles. But you can also use ExpansionTileItem widget when more control is required. All the properties overrides the that of ExpansionTileList.

  • trailing allows you to specify the trailing widget for the tile.
  • trailingAnimation allows you to specify a custom animation for the trailing widget.
  • enableTrailingAnimation allows you to enable or disable the trailing animation.

Installation

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

dependencies:
  flutter:
    sdk: flutter
  expansion_tile_list: ^1.0.2

Usage

Import the package:

import 'package:expansion_tile_list/expansion_tile_list.dart';

Example

Here are some simple examples of how to use the ExpansionTileList: check out the demo

  1. Basic usage: create a list of ExpansionTile widgets using the ExpansionTileList widget.
import 'package:flutter/material.dart';
import 'package:expansion_tile_list/expansion_tile_list.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: ExpansionTileList(
          tileGapSize: 10.0,
          children: <Widget>[
            ExpansionTile(
              title: Text('Tile 1'),
              children: <Widget>[
                Text('Child 1'),
              ],
            ),
            ExpansionTile(
              title: Text('Tile 2'),
              children: <Widget>[
                Text('Child 2'),
              ],
            ),
          ],
        ),
      ),
    );
  }
}
  1. Using trailing and trailingAnimation: use the trailing and trailingAnimation properties to customize the trailing widget of the tiles.

var expansionTileList =
ExpansionTileList(
  trailing: Icon(Icons.arrow_drop_down),
  trailingAnimation: ExpansionTileAnimation(
    tween: Tween<double>(begin: 0, end: 0.5),
    duration: Duration(milliseconds: 200),
    curve: Curves.easeInOut,
    builder: (context, index, value, child) {
      return Transform.rotate(
        angle: value * pi,
        child: child,
      );
    },
  ),
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using separatorBuilder: This property allows you to customize the appearance of the separators between the tiles in the list.

var expansionTileList =
ExpansionTileList(
  separatorBuilder: (context, index, value, child) {
    return Divider(
      color: Colors.blue,
      height: 2.0,
    );
  },
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using tileBuilder: This property allows you to customize the appearance of the tiles in the list.

var expansionTileList = ExpansionTileList(
  tileBuilder: (context, index, isExpanded, child) {
    return Container(
      color: isExpanded ? Colors.blue : Colors.white,
      child: child,
    );
  },
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using controller: This property allows you to programmatically control the expansion of the tiles.

var controller = ExpansionTileListController();

var expansionTileList = ExpansionTileList(
  controller: controller,
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);

_() {
  /// Expand the first tile
  controller.expand(0);

  /// Collapse the first  tile
  controller.collapse(0);

  /// Toggle the first 
  controller.toggle(0);

  /// Expand all 
  controller.expandAll();

  /// Collapse all tiles
  controller.collapseAll();
}
  1. Using onExpansionChanged: This property allows you to listen to the expansion changes of the tiles.

var expansionTileList = ExpansionTileList(
  onExpansionChanged: (index, isExpanded) {
    print('Tile $index is ${isExpanded ? 'expanded' : 'collapsed'}');
  },
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using ExpansionMode: Use ExpansionMode property of the ExpansionTileList widget to control the expansion of the tiles. The initialExpandedIndexes property allows you to specify the indexes of the tiles that are initially expanded. ExpansionMode that enforces a single tile expansions at a time expects a single index in the array initialExpandedIndexes i.e. ExpansionMode.atMostOne and ExpansionMode.exactlyOne, if multiple indexes are specified then only the first index at 0 is considered. If the initialExpandedIndexes is not specified then the first tile is expanded by default.

NOTE: ExpansionMode that allows at lease one tile to be always expanded i.e. ExpansionMode.atLeastOne and ExpansionMode.exactlyOne disables the ExpansionTile widget to enforce this rule.

/// Use ExpansionMode property
/// length of `initialExpandedIndexes` for enforces at least one tile always expanded [`ExpansionMode.atLeastOne`, `ExpansionMode.exactlyOne`] should be 1 or 0.
var expansionTileList = ExpansionTileList(
  initialExpandedIndexes: [0, 1], // defaults to [] if not specified
  expansionMode: ExpansionMode.any, // defaults to ExpansionMode.any if not specified
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);

// Use named constructor
var expansionTileList = ExpansionTileList(
  expansionMode: ExpansionMode.atMostOne,
  initialExpandedIndexes: [0], // defaults to [] if not specified
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);

var expansionTileList = ExpansionTileList(
  expansionMode: ExpansionMode.atLeastOne,
  initialExpandedIndexes: [1],
  // defaults to [0] if not specified and cannot be resolved by first initialExpandedIndex of children
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);

var expansionTileList = ExpansionTileList(
  expansionMode: ExpansionMode.exactlyOne,
  initialExpandedIndexes: [0], // defaults to [0] if not specified
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using ExpansionTileList.single named constructor: Use the ExpansionTileList.single named constructor to create a list of tiles with either the ExpansionMode.atMostOne or ExpansionMode.exactlyOne expansion mode.

var expansionTileList = ExpansionTileList.single(
  initialExpandedIndex: 0,
  children: <ExpansionTile>[
    ExpansionTile(
      title: Text('Tile 1'),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTile(
      title: Text('Tile 2'),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);

// Use ExpansionMode.atMostOne  named constructor
  1. Using ExpansionTileItem: Use the ExpansionTileItem widget to customize the trailing widget of the tiles.

var expansionTileList = ExpansionTileList(
  children: <ExpansionTile>[
    ExpansionTileItem(
      title: Text('Tile 1'),
      trailing: Icon(Icons.arrow_drop_down),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTileItem(
      title: Text('Tile 2'),
      trailing: Icon(Icons.arrow_drop_down),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using ExpansionTileItem with trailingAnimation: Use the ExpansionTileItem widget with the trailingAnimation property to customize the trailing widget of the tiles.

var expansionTileList = ExpansionTileList(
  children: <ExpansionTile>[
    ExpansionTileItem(
      title: Text('Tile 1'),
      trailing: Icon(Icons.arrow_drop_down),
      trailingAnimation: Tween<double>(begin: 0, end: 0.5),
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTileItem(
      title: Text('Tile 2'),
      trailing: Icon(Icons.arrow_drop_down),
      trailingAnimation: Tween<double>(begin: 0, end: 0.5),
      children: <Widget>[Text('Child 2')],
    ),
  ],
);
  1. Using ExpansionTileItem with trailingAnimationBuilder: Use the ExpansionTileItem widget with the trailingAnimationBuilder property to customize the trailing widget of the tiles.

var expansionTileList = ExpansionTileList(
  children: <ExpansionTile>[
    ExpansionTileItem(
      title: Text('Tile 1'),
      trailing: Icon(Icons.arrow_drop_down),
      trailingAnimationBuilder: (context, index, value, child) {
        return Transform.rotate(
          angle: value * pi,
          child: child,
        );
      },
      children: <Widget>[Text('Child 1')],
    ),
    ExpansionTileItem(
      title: Text('Tile 2'),
      trailing: Icon(Icons.arrow_drop_down),
      trailingAnimationBuilder: (context, index, value, child) {
        return Transform.rotate(
          angle: value * pi,
          child: child,
        );
      },
      children: <Widget>[Text('Child 2')],
    ),
  ],
);

How initialExpandedIndexes with ExpansionMode works

  • ExpansionMode.atMostOne
    • considers initialExpandedIndexes first valid index.
    • considers first ExpansionTile child widget withinitiallyExpanded true.
    • collapses all tiles.
  • ExpansionMode.exactlyOne
    • considers initialExpandedIndexes first valid index.
    • considers first ExpansionTile child widget withinitiallyExpanded true.
    • considers first ExpansionTile child widget at index 0.
  • ExpansionMode.atLeastOne
    • considers initialExpandedIndexes all indexes if not empty.
    • considers all ExpansionTile children widget withinitiallyExpanded true.
    • considers first ExpansionTile child widget at index 0.
  • ExpansionMode.any
    • considers initialExpandedIndexes all indexes if not empty.
    • considers all ExpansionTile children widget withinitiallyExpanded true.
    • collapses all tiles.

How tileGapSize and separatorBuilder layout works

  • tileGapSize is the size of the gap between the tiles in the list.
  • separatorBuilder is the builder for the separator between the tiles in the list. Note: tileGapSize is always rendered before the separatorBuilder if both are specified.
  • Layout as follows:
[ExpansionTile 1]
[Gap]
[Divider]
[ExpansionTile 2]
[Gap]
[Divider]
[ExpansionTile 3]

Group Properties

Property Description Default Value
key The widget key. null
children The list of ExpansionTile widgets that are managed by this widget. required
onExpansionChanged Called whenever a tile is expanded or collapsed. null
tileGapSize The size of the gap between the tiles in the list. 0.0
separatorBuilder The builder for the separator between the tiles in the list. null
tileBuilder A builder that can be used to customize the appearance of the tiles. null
controller A controller that can be used to programmatically control the expansion of the tiles. null
trailing The widget that is displayed at the end of each tile header. Can be overridden by trailing property of ExpansionTile null
trailingAnimation The animation for the trailing widget of the tiles. Can be overridden by trailingAnimation property of ExpansionTile null
enableTrailingAnimation Enable or disable the trailing animation. true
initialExpandedIndexes The indexes of the tiles that are initially expanded. const <int>[]
expansionMode The expansion mode of the ExpansionTileList. ExpansionMode.any

Item Properties

Property Description Default Value
controller Programmatically control the expansion using ExpansionTileController or ExpansionTileItemController. null
trailing The widget that is displayed at the end of each tile header. null
trailingAnimation The animation for the trailing widget of the tiles. null
enableTrailingAnimation Enable or disable the trailing animation. true

Testing

All testcase are available for the package.

  • expansion_tile_list_test.dart
  • expansion_tile_item_test.dart
  • expansion_tile_extension_test.dart To run the tests, use the following command:
flutter test

Troubleshooting

  1. If you encounter any issues while using the package, please check the GitHub issues page to see if the issue has already been reported.
  2. If you are unable to find a solution, please create a new issue with a detailed description of the problem, including the steps to reproduce it.
  3. If you have any questions or need help with the package, please feel free to reach out to the package maintainer.
  4. If you would like to contribute to the package, please refer to the Contributing section for more information.
  5. If you have any feedback or suggestions for the package, please share them with the package maintainer.

Known Issues

  • State Management issues with ExpansionTile children: Set maintainState to true for the ExpansionTile children to maintain the state of the children when the parent ExpansionTileList is rebuilt.
  • Expansion state issues: The expansion state of the ExpansionTile may not be maintained when the parent of ExpansionTileList is rebuilt due to the change of the widget tree. To maintain the expansion state, use a GlobalKey.
  • ExpansionTileList tileBuilder issues: If the tileBuilder modifies the widget tree during a rebuild, it may disrupt the maintenance of the expansion state of the ExpansionTile. To address this, use a GlobalKey on the ExpansionTile.
  • ExpansionTileController controller issues: The controller property may not function as expected when the ExpansionTile modifies the widget is modified tree during a rebuild. To resolve this, use a GlobalKey or delegate the management of the controller to ExpansionTileList using ExpansionTileItemController.
  Failed assertion: line 607 pos 12: 'widget.controller?._state == null': is not true.

These issues are due to the ExpansionTile widget limitations and not the package. We have ensured that the package works as expected with the Flutter framework and made sure to take a safe decision to mitigate these issues. This means no issues should be encountered when using the package as intended.

Contributing

Contributions are welcome! If you find a bug or want a feature, please fill an issue. If you want to contribute code, please submit a pull request. We welcome contributions from everyone. Before you start:

  1. Fork the repository to your own GitHub account.
  2. Clone the project to your machine.
  3. Create a branch locally with a descriptive name.
  4. Commit changes to the branch.
  5. Push changes to your fork.
  6. Create a new pull request in GitHub and link the issue you are fixing.

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License

This project is licensed under the BSD-style license. See the License file for details.

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Libraries

expansion_tile_list
ExpansionTileList is a Flutter package that allows you to create a list of ExpansionTile widgets. It provides a highly customisable list of expansion tiles with extensive options for appearance, animations, and control over expansion behaviour, while simplifying common features.