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How to change flutter dialog color when dialog is open?


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??


Solution

  • 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 MaterialApp(
              theme: ThemeData.light(),
              darkTheme: ThemeData.dark(),
              themeMode: ThemeMode.system, // 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(
                              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'),
                        ),*/
    
    
    
                      ],
                    ),
                  );
                },
              ),
            );
          },
        );
      }
    }