如何在颤抖中抓住抽屉的打开和关闭? [英] How catch the opening and closing of the drawer in flutter?

问题描述

我如何才能在混乱中抓住抽屉的打开和关闭?原则上，必须为此使用两个对象:DrawerController，它保存"抽屉和抽屉回调.抽屉式回调应该跟踪抽屉的打开和关闭，但是在 https://上讨论的代码github.com/flutter/flutter/issues/21272 和 https://github. com/flutter/flutter/issues/23630 不起作用.有人可以提供建议吗?

How can I catch the opening and closing of the drawer in flutter? In principle, two objects must be are used for this purpose: DrawerController, which "holds" the drawer and the drawerCallback. drawerCallback should track the opening and closing of the drawer, but the code that is discussed at https://github.com/flutter/flutter/issues/21272 and https://github.com/flutter/flutter/issues/23630 does not works. Anyone can advise something?

推荐答案

您可以先参考其他人对stackoverflow的回复

You can first refer to other people's replies on stackoverflow here

我的解决方法:

在DrawerWidget上获取抽屉状态

get Drawer status on DrawerWidget

initState() : open drawer
dispose() : close drawer

DrawerService Provider提供的流抽屉状态

Stream drawer status by DrawerService Provider

查看完整代码

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

import 'package:provider/provider.dart';


void main() {
  runApp(
    MultiProvider(
      providers: [
        Provider(create: (_) => DrawerService()),
      ],
      child: MyApp(),
    ),
  );
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  DrawerService _drawerService;
  String drawerStatus = 'close';
  @override
  void initState() {
    super.initState();
    _drawerService = Provider.of(context, listen: false);
    _listenDrawerService();
  }

  _listenDrawerService() {
    _drawerService.status.listen((status) {
      if(status) {
        drawerStatus = 'open';
      } else {
        drawerStatus = 'close';
      }
      setState(() { });
    });
  }

  @override
  Widget build(BuildContext context) {
    Color bgColor = Colors.yellow;
    if(drawerStatus == 'open') {
      bgColor = Colors.red;
    }

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      drawer: DrawerWidget(),
      body: Container(
        decoration: BoxDecoration(color: bgColor),
        height: 300,
        child: Center(child: Text(drawerStatus),),
      ),
    );
  }
}


class DrawerWidget extends StatefulWidget {
  @override
  _DrawerWidgetState createState() => _DrawerWidgetState();
}

class _DrawerWidgetState extends State<DrawerWidget> {  
  DrawerService _drawerService;

  @override
  void initState() {
    super.initState();
    _drawerService = Provider.of(context, listen: false);
    _drawerService.setIsOpenStatus(true);
  }

  @override
  Widget build(BuildContext context) {
    return Drawer(
      child: Center(child: Text('drawer'),),
    );
  }

  @override
  void dispose() {
    super.dispose();
    _drawerService.setIsOpenStatus(false);
  }
}

class DrawerService {
  StreamController<bool> _statusController = StreamController.broadcast();
  Stream<bool> get status => _statusController.stream;

  setIsOpenStatus(bool openStatus) {
    _statusController.add(openStatus);
  }
}

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