Flutter：如何在 Flutter 中使用 Switch 更改主题 - 我已使用 Provider 实现了此明暗主题，但无法使用 switch 更改

Question

I have used the provider for changing themes, this is the code for light and dark theme. The main purpose of my question is to change the theme with a switch, not with a button. The theme can be changed with a button correctly using "int mode". But when I use "bool mode" because of a switch. The switch needs a value of true or false.

How to implement this switch for changing the light and dark theme? I need a switch, not a button.

import 'package:flutter/material.dart';

class AppStyleModeNotifier extends ChangeNotifier {
  bool mode = true; //0 for light and 1 for dark
  Color primaryBackgroundColor = Colors.white;
  Color appBarBackgroundColor = Colors.cyan[200];
  Color boxColor = Colors.blue[50];
  Color boxTextColor = Colors.indigo;
  Color primaryTextColor = Colors.white;
  Color dashboardColor = Colors.cyan;
  Color dashboardTextColor = Colors.red[600];
  Color dashboardIconColor = Colors.yellow[200];
  //Color typeMessageBoxColor = Colors.grey[200];

  switchMode() {
    if (mode == true) {
      //if it is light mode currently switch to dark
      primaryBackgroundColor = Colors.grey[900];
      appBarBackgroundColor = Colors.grey[800];
      // boxColor = Colors.grey[600];
      boxColor = Colors.black;
      boxTextColor = Colors.grey[100];
      primaryTextColor = Colors.black;
      dashboardColor = Colors.grey[900];
      dashboardTextColor = Colors.grey[400];
      dashboardIconColor = Colors.white;
      //typeMessageBoxColor = Colors.grey[800];
      mode = false;
    } else {
      //if it is dark mode currently switch to light
      primaryBackgroundColor = Colors.white;
      appBarBackgroundColor = Colors.cyan[200];
      boxColor = Colors.tealAccent;
      boxTextColor = Colors.indigo;
      primaryTextColor = Colors.white;
      dashboardColor = Colors.cyan;
      dashboardTextColor = Colors.red[600];
      dashboardIconColor = Colors.yellow[200];
      //typeMessageBoxColor = Colors.grey[200];
      mode = true;
    }

    notifyListeners();
  }
}

Following is the Switch for changing the light and dark theme. This Switch is not working correctly, Is there any mistake in the code. Instead of a switch using a button, it works fine.

import 'package:provider/provider.dart';
import '../FreelanceTheme/AppStyleModeNotifier.dart';

class HomePage extends StatelessWidget with NavigationStates {

  const HomePage({Key key, this.onMenuTap}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final appStyleMode = Provider.of<AppStyleModeNotifier>(context);
    return MaterialApp(
      home: Scaffold(
        backgroundColor: Color(0xffE5E5E5),
        appBar: AppBar(
          elevation: 0,
          backgroundColor: appStyleMode.appBarBackgroundColor,
          actions: <Widget>[
            Switch(
              value: appStyleMode.mode,
              onChanged: appStyleMode.switchMode(),
            ),

Answer 1

Change your code to this, it'll be work.

Switch(
  value: appStyleMode.mode,
  onChanged: (value)=> appStyleMode.switchMode(),
),