Блог

На самом деле, я хочу добавить больше элементов в элемент внутри выпадающего списка, например, Web. Пожалуйста, помогите мне, спасибо.

Я создал собственный виджет, подобный этому…

 import 'dart:math';
import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        body: SafeArea(
          child: MyHomePage(),
        ),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return ListView(
      children: [
        Accordion(
            title: 'Level1',
            child: Column(
              children: [
                Accordion(
                  title: 'Level2',
                  child: Accordion(
                    title: 'Level3',
                    child: Column(
                      children: [
                        Accordion(
                          title: 'Level4',
                          child: Text('Level4 content'),
                        ),
                      ],
                    ),
                  ),
                ),
                Accordion(
                  title: 'Level2',
                  child: Text('Level2 content'),
                ),
              ],
            )),
        Accordion(
          title: 'Level1',
          child: Text('Level1 content'),
        ),
      ],
    );
  }
}

class Accordion extends StatefulWidget {
  const Accordion({
    Key key,
    @required this.title,
    @required this.child,
  }) : super(key: key);

  final String title;
  final Widget child;
  @override
  _AccordionState createState() => _AccordionState();
}

class _AccordionState extends State<Accordion>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<double> _heightFactor;
  Animation _colorTween;

  bool _isExpanded = false;

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  void _handleTap() {
    setState(() {
      _isExpanded = !_isExpanded;
      if (_isExpanded) {
        _controller.forward();
      } else {
        _controller.reverse().then<void>((value) {
          if (!mounted) return;
          setState(() {});
        });
      }
    });
  }

  @override
  void initState() {
    _controller = AnimationController(
      duration: Duration(
        milliseconds: 150,
      ),
      vsync: this,
    );
    _heightFactor = _controller.drive(CurveTween(curve: Curves.easeIn));
    _colorTween = ColorTween(
      begin: Colors.grey,
      end: Colors.black87,
    ).animate(CurvedAnimation(parent: _controller, curve: Curves.easeIn));
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
        animation: _controller.view,
        builder: (_, __) {
          return Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              GestureDetector(
                behavior: HitTestBehavior.opaque,
                child: Padding(
                  padding: EdgeInsets.fromLTRB(10, 10, 0, 10),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: <Widget>[
                      Flexible(
                        child: Text(
                          widget.title,
                          style: TextStyle(
                            fontWeight: FontWeight.bold,
                          ),
                        ),
                      ),
                      Transform.rotate(
                        angle: pi * _heightFactor.value * 0.5,
                        child: Icon(
                          Icons.arrow_forward_ios,
                          color: _colorTween.value,
                        ),
                      )
                    ],
                  ),
                ),
                onTap: _handleTap,
              ),
              ClipRect(
                child: Align(
                  alignment: Alignment.centerLeft,
                  heightFactor: _heightFactor.value,
                  child: Padding(
                    padding: EdgeInsets.only(bottom: 10, left: 10),
                    child: widget.child,
                  ),
                ),
              ),
            ],
          );
        });
  }
}