flutter - Flutter 如何在特定屏幕上强制使用暗模式

Question

我正在使用颤振构建一个新闻应用程序，该应用程序有 2 种主题模式已经黑暗和明亮的手机设置和工作非常好，但我需要在我的应用程序的某些屏幕上变暗，例如视频部分或视频页面。 ..ETC

我用谷歌搜索了这个和所有关于我已经做过的正常主题的结果。

我认为没有任何代码可以在这里提供帮助，但如果有请告诉我！

标签： flutterdartflutter-layout

Answer 1

您可以随时覆盖当前主题，只需将所需的小部件放在Theme 类中即可。我不知道您是否使用 Scaffold，但假设您是，那么您需要做的就是：

// declare theme data if you don't have it already
final ThemeData specialThemeData = ThemeData(
  brightness: Brightness.dark,
  primaryColor: Colors.yellow[700],
  // and so on...
);
 
 
  @override
  Widget build(BuildContext context) {
    // this the point of interest, return a Theme with desired Theme Data
    return Theme(
      data: specialThemeData,
      child: Scaffold( 
      //...

它不必是 Scaffold，它可以在任何 Widegt 上工作。

这是一个功能齐全的示例，您可以自己尝试：

import 'package:flutter/material.dart';

final ThemeData specialThemeData = ThemeData(
  brightness: Brightness.dark,
  primaryColor: Colors.yellow[700],
  accentColor: Colors.orange[500],

  textTheme: TextTheme(
    headline1: TextStyle(fontSize: 48.0, fontWeight: FontWeight.bold),
    headline6: TextStyle(fontSize: 24.0, fontStyle: FontStyle.italic),
    bodyText2: TextStyle(fontSize: 18.0),
  ),
);

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

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

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  void _goToSpecialPage() {
    Navigator.push(
        context,
        MaterialPageRoute(
            builder: (context) => MySpecialPage()
        )
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text('Your homepage, using default theme.',),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _goToSpecialPage,
        tooltip: 'Go to special page',
        child: Icon(Icons.navigate_next),
      ),
    );
  }
}

class MySpecialPage extends StatefulWidget {
  MySpecialPage({Key key}) : super(key: key);
  @override
  _MySpecialPageState createState() => _MySpecialPageState();
}

class _MySpecialPageState extends State<MySpecialPage> {
  void _backToHomePage(){
    Navigator.pop(context);
  }

  @override
  Widget build(BuildContext context) {
    // this the point of interest, return a Theme with desired Theme Data
    return Theme(
      data: specialThemeData,
      child: Scaffold(
        appBar: AppBar(
          title: Text('Special theme page'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text('Your special page that uses a different theme.',),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: _backToHomePage,
          tooltip: 'Go back to home page',
          child: Icon(Icons.navigate_before),
        ),
      ),
    );
  }
}