flutter-展开闭合效果（列表型式的）

import ‘package:flutter/material.dart‘;

class ExpansionTileDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: AppBar(title: Text(‘expansionTile‘),),),
      body: Center(
        child: ExpansionTile(
          title: Text(‘Expansion Tile‘),//标题
          leading: Icon(Icons.ac_unit),//左边的图标
          backgroundColor: Colors.white12,
          children: <Widget>[
            ListTile(
              title: Text(‘list tile‘),
              subtitle: Text(‘subtitle‘),
            )
          ],
          initiallyExpanded: true,//默认打开关闭
        ),
      ),
    );
  }
}

import ‘package:flutter/material.dart‘;

class ExpansionTileList extends StatefulWidget {
  @override
  _ExpansionTileListState createState() => _ExpansionTileListState();
}

class _ExpansionTileListState extends State<ExpansionTileList> {

  List<int> mList;
  List<ExpanStateBean> expandStateList;

  _ExpansionTileListState(){
    mList=new List();
    expandStateList=new List();
    for(int i=0;i<10;i++){
      mList.add(i);
      expandStateList.add(ExpanStateBean(i,false));
    }
  }

  _setCurrentIndex(int index,isExpand){
    setState(() {
      expandStateList.forEach((item) { 
        if(item.index == index){
          item.isOpen =!isExpand;
        }
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text("expansion panel list"),),
      body: SingleChildScrollView(
        child: ExpansionPanelList(// 点击的回调函数
          expansionCallback: (index,bol){
            _setCurrentIndex(index,bol);
          },
          children: mList.map((index){
            return ExpansionPanel(
              headerBuilder: (context,isExpanded){ //headerBuilder:头部   isExpanded是否打开
                return ListTile(
                  title:Text(‘this is No.$index‘)
                );
              },
              body: ListTile(
                title: Text(‘expansion no.$index‘),
              ),
              isExpanded: expandStateList[index].isOpen
            );
          }).toList(),
        ),
      ),
    );
  }
}

// 控制打开和闭合的类
class ExpanStateBean{
  var isOpen;
  var index;
  ExpanStateBean(this.index,this.isOpen);
}