Problem when switching system language on android

[uberchilly]

Describe the bug
Switching system language in settings and going back to the app on android doesn't change the app's language

**Reproduction code
example:

import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:get/get_navigation/get_navigation.dart';
import 'package:google_fonts/google_fonts.dart';

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

class Messages extends Translations {
  @override
  Map<String, Map<String, String>> get keys => {
        'en_US': {
          'login': 'Login',
          'registration': "Registration",
          'nexoslav': 'Nexoslav',
        },
        'fr_FR': {
          'login': 'sdkadmka',
          'registration': 'sad,amdkadmka',
          'nexoslav': 'n21uijn31n3hjqnhj',
        }
      };
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return GetMaterialApp(
      translations: Messages(),
      // your translations
      fallbackLocale: Locale('en', 'US'),
      locale: Get.deviceLocale,
      supportedLocales: [Locale('en', 'US'), Locale('fr', 'FR')],
      title: 'Flutter Demo',
      theme: MyTheme.themeLight(),
      darkTheme: MyTheme.themeDark(),
      home: LoginStartScreen(),
    );
  }
}

class LoginStartScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    context
        .theme; //this is necessary so that widget gets rebuild with new theme
    return Scaffold(
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 34.0),
          child: Column(
            mainAxisSize: MainAxisSize.max,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Padding(
                padding: const EdgeInsets.only(top: 15.0),
                child: Icon(
                  Icons.wc,
                  size: 20.0,
                ),
              ),
              Expanded(
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Flexible(
                      child: Container(),
                      flex: 1,
                    ),
                    GestureDetector(
                      onTap: () {},
                      child: Text(
                        "Hello ${Get.deviceLocale.toString()}",
                        style: MyTheme.pageTitle(),
                      ),
                    ),
                    Padding(
                      padding: const EdgeInsets.only(top: 16.0),
                      child: Text(
                        "Bring transparency to your energy and be part of tomorrow\'s energy supply. With \"Home\" you build up the necessary knowledge and know-how about your energy and CO₂ consumption. You can track and analyse your data in real-time and make the right decisions, e.g. choose an electricity product from local, sustainable energy sources.",
                        style: MyTheme.body(),
                      ),
                    ),
                    Flexible(
                      child: Container(),
                      flex: 2,
                    ),
                  ],
                ),
              ),
              ElevatedButton(
                style: ElevatedButton.styleFrom(
                  padding: EdgeInsets.symmetric(vertical: 12),
                  shape: const RoundedRectangleBorder(
                    borderRadius: BorderRadius.all(Radius.circular(34.0)),
                  ),
                ),
                onPressed: () {
                  Get.updateLocale(Locale("en", "US"));
                },
                child: Text('registration'.tr),
              ),
              ElevatedButton(
                onPressed: () {
                  Get.updateLocale(Locale("fr", "FR"));
                },
                style: ElevatedButton.styleFrom(
                  padding: EdgeInsets.symmetric(vertical: 12),
                  shape: const RoundedRectangleBorder(
                    borderRadius: BorderRadius.all(Radius.circular(34.0)),
                  ),
                ),
                child: Text(
                  'login'.tr,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class MyColors {
  static final backgroundColorLight = HexColor.fromHex('#F0F7F3');
  static final backgroundColorDark = HexColor.fromHex('#293330');
  static Color backgroundColor =
  Get.isPlatformDarkMode ? backgroundColorDark : backgroundColorLight;

  static final textColorLight = HexColor.fromHex('#293330');
  static final textColorDark = HexColor.fromHex('#FFFFFF');
  static Color textColor() =>
      Get.isPlatformDarkMode ? textColorDark : textColorLight;
}

class MyTheme {
  static themeLight() => ThemeData.light().copyWith(
    scaffoldBackgroundColor: MyColors.backgroundColorLight,
  );

  static themeDark() => ThemeData.dark().copyWith(
    scaffoldBackgroundColor: MyColors.backgroundColorDark,
  );

  static TextStyle mainTextStyle() => GoogleFonts.openSans(
    fontWeight: FontWeight.w400,
    color: MyColors.textColor(),
  );

  static TextStyle mainTextStyleBold() => mainTextStyle().copyWith(
    fontWeight: FontWeight.w700,
  );

  static TextStyle pageTitle() => mainTextStyleBold().copyWith(fontSize: 22.0);

  static TextStyle paragraph() => mainTextStyle().copyWith(fontSize: 14.0);

  static TextStyle body() => mainTextStyle().copyWith(
    fontSize: 16.0,
    fontFeatures: [FontFeature("tnum"), FontFeature('lnum')],
    height: 1,
  );

  static TextStyle bodyBold() => body().copyWith(
    fontWeight: FontWeight.w700,
  );
}

extension HexColor on Color {
  /// String is in the format "aabbcc" or "ffaabbcc" with an optional leading "#".
  static Color fromHex(String hexString) {
    final buffer = StringBuffer();
    if (hexString.length == 6 || hexString.length == 7) buffer.write('ff');
    buffer.write(hexString.replaceFirst('#', ''));
    return Color(int.parse(buffer.toString(), radix: 16));
  }

  /// Prefixes a hash sign if [leadingHashSign] is set to `true` (default is `true`).
  String toHex({bool leadingHashSign = true}) => '${leadingHashSign ? '#' : ''}'
      '${alpha.toRadixString(16).padLeft(2, '0')}'
      '${red.toRadixString(16).padLeft(2, '0')}'
      '${green.toRadixString(16).padLeft(2, '0')}'
      '${blue.toRadixString(16).padLeft(2, '0')}';
}

To Reproduce
Steps to reproduce the behavior:

1. Open the app, it will pick up system language correctly
2. Open android's system settings and swich language from en_US to fr_FR
3. Return back to the app
4. See app still displaying en_US

Expected behavior
App changes language to fr_FR

Screenshots

Flutter Version:
Flutter (Channel stable, 2.2.3, on Microsoft Windows [Version 10.0.19042.1110]

Getx Version:
^4.3.0

Describe on which device you found the bug:
Samsung galaxy s21 and every other device and emulator that I have tried

[eduardoflorence]

Hi @uberchilly, I have an example of language switching at the link below, see if it can help you

https://gist.github.com/eduardoflorence/9503ca35950559618da71f55a74b6562

[uberchilly]

@eduardoflorence Thank you. I am not trying to switch language by user action, I am trying to make my app follow the system's language like it is the default behavior on Android. Will the code sample above do that?

[ghost]

Hello, i am irritated too, how do i watch the device locale with getX? When deviceLocale (Get.deviceLocale) is changed in system settings i want to change my app automatically - but actually I have no idea how to hook in the deviceLocale?

I would like to get the minimum sample code for it please

[ghost]

@uberchilly Do you have a solution so far?

[ghost]

@jonataslaw can you help please? How to simply watch deviceLocale ?

[ghost]

I did it using WidgetsBindingObserver in AppLifecycleState.resumed. This is the preferred solution @uberchilly

You can go this way (...Get.updateLocale(Get.deviceLocale!);...) or even directly in didChangeLocales().

[jonataslaw]

Maybe related #2019

[uberchilly]

This works for me in getx 4.5.1. I am closing the issue.