I used the Dialog widget inside showDialog method in flutter, the dialog is working fine, but when the dialog is open and I change color mode(Light, Dark) from the setting, it changes the theme of the entire app, but not the dialog theme until I close and open the dialog again. Any idea how I can resolve this??

CodePudding user response：

It will be more helpful if you can provide us some code

CodePudding user response：

create dummy project change theme

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}


final ValueNotifier<ThemeMode> _notifier = ValueNotifier(ThemeMode.light);
bool isLightMode = true;

class MyApp extends StatelessWidget {


  @override
  Widget build(BuildContext context) {
    return ValueListenableBuilder<ThemeMode>(
      valueListenable: _notifier,
      builder: (_, mode, __) {
        return MaterialApp(
          theme: ThemeData.light(),
          darkTheme: ThemeData.dark(),
          themeMode: mode, // Decides which theme to show, light or dark.
          home: const MyHomePage(title: 'Flutter Demo Home Page'),
        );
      },
    );
  }
}

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

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter  ;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also a layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in Android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              onPressed: () {
                isLightMode ? _notifier.value = ThemeMode.dark : _notifier.value = ThemeMode.light;
                setState(() {
                  isLightMode = !isLightMode;
                });
              },
              child: Text('Toggle Theme'),
            ),
            ElevatedButton(
              onPressed: () => _showFontDialog(),
              child: Text('Show dialog'),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }

  _showFontDialog() {
    showDialog<void>(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          insetPadding: EdgeInsets.all(30),
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(30),
          ),
          content: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Container(
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  mainAxisAlignment: MainAxisAlignment.start,
                  crossAxisAlignment: CrossAxisAlignment.center,
                  children: <Widget>[
                    Container(
                      alignment: Alignment.topLeft,
                      child: const Text(
                        'This dialog Change Theme',
                        style: TextStyle(
                          color: Colors.black,
                          fontSize: 20,
                          fontFamily: 'Roboto',
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                    ),
                    SizedBox(
                      height: 50,
                    ),
                    ElevatedButton(
                      onPressed: () {
                        isLightMode ? _notifier.value = ThemeMode.dark : _notifier.value = ThemeMode.light;
                        setState(() {
                          isLightMode = !isLightMode;
                        });
                      },
                      child: Text('Toggle Theme'),
                    ),



                  ],
                ),
              );
            },
          ),
        );
      },
    );
  }
}