expansion_widget

An edited version of Expansion Tile that allows you customize tile widget and animation.

Parameters

key	Key?
titleBuilder	Widget Function( animationValue, easeInValue, isExpanded, toggleFunction)	required The builder of title. Typically a [Button] widget that call [toggleFunction] when pressed.
content	Widget	required The widget that are displayed when the expansionWidget expands.
initiallyExpanded	bool	default: false Specifies if the expansionWidget is initially expanded (true) or collapsed (false, the default).
maintainState	bool	default: false Specifies whether the state of the content is maintained when the expansionWidget expands and collapses.
expandedAlignment	Alignment?	default: Alignment.center Specifies the alignment of [content], which are arranged in a column when the expansionWidget is expanded.
onSaveState	Function (bool isExpanded)?	Function to save expansion state Called when expansion state changed
onRestoreState	bool? Function()?	default: null function to restore expansion state. Return null if there is no state to store, in this case, [initiallyExpanded] will be used
duration	Duration	default: 200 ms The length of time of animation
onExpansionWillChange	bool Function(bool)?	default: null Called when the widget will change expanded state. When the widget is going to start expanding/collapsing, this function is called with the value true/false. Return false to prevent expanded state to change. Return true(default) to allow expanded state changing.
onExpansionChanged	Function(bool)?	default: null Called when the widget expands or collapses. When the widget starts expanding, this function is called with the value true. When the tile starts collapsing, this function is called with the value false.

Usage

import 'package:expansion_widget/expansion_widget.dart';
import 'dart:math' as math;

ExpansionWidget(
    initiallyExpanded: true,
    titleBuilder: (double animationValue, _, bool isExpaned, toogleFunction) {
      return InkWell(
          onTap: () => toogleFunction(animated: true),
          child: Padding(
            padding: EdgeInsets.all(8),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                Expanded(child: Text('Expansion Widget Title 1')),
                Transform.rotate(
                  angle: math.pi * animationValue / 2,
                  child: Icon(Icons.arrow_right, size: 40),
                  alignment: Alignment.center,
                )
              ],
            ),
          ));
    },
    content: Container(
      width: double.infinity,
      color: Colors.grey.shade100,
      padding: EdgeInsets.all(20),
      child: Text('Expaned Content'),
    ))

Or using ExpansionWidget.autoSaveState() to auto save/restore expansion state.