flutter 列表开合效果

最新推荐文章于 2025-01-14 17:22:17 发布

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本文介绍如何使用 Flutter 中的 ExpansionPanelList 控件，展示了一个实例，展示了如何通过 ExpansionPanelList 动态切换面板展开状态，并管理各个面板的展开状态。通过 setState 更新列表中每个 item 的 isOpen 值，实现了数据驱动的交互效果。

效果

import 'package:flutter/material.dart';

class ExpansionPanelListDemo extends StatefulWidget {
  ExpansionPanelListDemo({Key key}) : super(key: key);

  @override
  _ExpansionPanelListDemoState createState() => _ExpansionPanelListDemoState();
}

class _ExpansionPanelListDemoState extends State<ExpansionPanelListDemo> {
  var currentPanelIndex = -1;
  List<int> mList;
  List<ExpandStateBean> expandStateList;

  _ExpansionPanelListDemoState(){
    mList = new List();
    expandStateList = new List();
    for (int i =0; i <10; i++){
      mList.add(i);
      expandStateList.add(ExpandStateBean(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('ExpansionPanel Demo'),),
      body: SingleChildScrollView(
       
       child: ExpansionPanelList(
         expansionCallback: (index,bol){
           _setCurrentIndex(index,bol);
         },
         children: mList.map((index){
            return ExpansionPanel(
              headerBuilder: (context,isExpanded){
                return ListTile(
                  title:Text('This is No.$index')
                );
              },
              body: ListTile(
                title: Text('expansion no $index')
              ),
              isExpanded: expandStateList[index].isOpen
            );
         }).toList(),
       ),
        ),
      );
  }
}

class ExpandStateBean{
  var isOpen;
  var index;
  ExpandStateBean(this.index,this.isOpen);
}