Expansion Tile List #

The ExpansionTileList widget is a container for the ExpansionTile widget that allows you to create a list of tiles. It provides additional features that empowers you to customize the appearance of the tiles and control their expansion programmatically.

Description #

The expansion_tile_list package provides a highly customizable list of expansion tiles for Flutter applications. It allows developers to create lists of expandable tiles with various customization options for appearance, animations, and control over the expansion state. The package supports features like global trailing widget, trailing animation, and different expansion modes to suit various use cases.

Check out the demo page to explore the latest features and experience the features firsthand!”

Features #

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.
• 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: ^0.1.1

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'),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

2. 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')],
    ),
  ],
);

3. 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')],
    ),
  ],
);

4. 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')],
    ),
  ],
);

5. 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 tilecontroller.collapse(0);
  /// Toggle the first tilecontroller.toggle(0);
  /// Expand all tilescontroller.expandAll();

  /// Collapse all tiles
  controller.collapseAll();
}

6. 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')],
    ),
  ],
);

7. 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, 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, 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')],
    ),
  ],
);

8. 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

8. 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')],
    ),
  ],
);

9. 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')],
    ),
  ],
);

10. 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]

Properties #

Testing #

All testcase are available for the package.

• expansion_tile_extension_test.dart
• expansion_tile_list_test.dart
• expansion_tile_item_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 ExpansionTileList is rebuilt due to the change of the widget tree. To maintain the expansion state, use a GlobalKey.
• ExpansionTileList tileBuilder issues: The tileBuilder property may not work as expected when the ExpansionTile is rebuilt due changes in the widget tree at runtime. To resolve this use a GlobalKey on the ExpansionTileList.
• ExpansionTileController controller issues: The controller property may not work as expected when the ExpansionTile is rebuilt due. To resolve this use a GlobalKey or ExpansionTileItemController to ensure.

  Failed assertion: line 607 pos 12: 'widget.controller?._state == null': is not true.

These issues are due to the Flutter framework 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 this 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.

Visitors #

License #

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