[英]Save a theme (Flutter/Dart)
早上好,這里有兩個按鈕可以更改我的應用程序的主題(淺色和深色)。 當我重新加載我的應用程序時,主題不是我最后選擇的主題。 我希望應用程序備份本地使用的最后一個主題。 您可能只需要保存一個數字,表明哪個主題使用了最后一個。 . . 但我完全不知道如何做到這一點?
這是代碼:main.dart
import 'package:flutter/material.dart';
import 'package:animated_splash_screen/animated_splash_screen.dart';
import 'package:watch/nav.dart';
import 'package:page_transition/page_transition.dart';
import 'package:watch/blocs/theme.dart';
import 'package:provider/provider.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ChangeNotifierProvider<ThemeChanger>(
builder: (_) => ThemeChanger(ThemeData.dark()),
child: MaterialAppWithTheme(),
);
}
}
class MaterialAppWithTheme extends StatelessWidget {
@override
Widget build(BuildContext context) {
final theme = Provider.of<ThemeChanger>(context);
return MaterialApp(
debugShowCheckedModeBanner: false,
theme: theme.getTheme(),
home: AnimatedSplashScreen(
duration: 3000,
splash: "",
splashTransition: SplashTransition.slideTransition,
pageTransitionType: PageTransitionType.downToUp,
nextScreen: Nav(),
),
);
}
}
設置.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:watch/blocs/theme.dart';
import 'package:watch/constants.dart';
class Parametres extends StatelessWidget {
@override
Widget build(BuildContext context) {
ThemeChanger _themeChanger = Provider.of<ThemeChanger>(context);
return Scaffold(
appBar: AppBar(
title: Text('Paramètres', style: kAppBarStyle,),
elevation: 0,
automaticallyImplyLeading: false,
leading: GestureDetector(
onTap: () {
Navigator.pop(context);
},
child: Icon(
Icons.arrow_back,
),
),
),
body: Container(
child: Column(
children: <Widget>[
FlatButton(
onPressed: () => _themeChanger.setTheme(
ThemeData(
bottomNavigationBarTheme: bNavBar,
scaffoldBackgroundColor: kBlackMedium,
brightness: Brightness.dark,
iconTheme: bIcons,
)),
child: Text('Dark Theme')),
FlatButton(
onPressed: () => _themeChanger.setTheme(
ThemeData(
bottomNavigationBarTheme: lNavBar,
scaffoldBackgroundColor: Colors.white,
brightness: Brightness.light,
iconTheme: lIcons,
primaryColor: kWhite,
)),
child: Text('Light Theme')),
],
),
),
);
}
}
謝謝
使用Shared Preference 包,您可以在那里將簡單值存儲為鍵對值。在初始屏幕的 init 中加載該數據,以便您可以根據主題顯示屏幕
您應該使用本地內存來保存主題。
您可以使用共享首選項或hive db 或sqflite或其他數據庫系統。
關於更改主題,您可以使用 Cubit、Bloc、Provider 等,甚至可以使用 ValueNotifier。
但是,您應該使用“您的狀態管理小部件”包裝 MaterialApp 或 CupertinoApp
並添加一些邏輯
或者您可以使用一些庫庫來更改主題
共享偏好是它的最佳選擇。 因為我不知道你的 ThemeChanger 類,所以我先在這里添加我的主題類:
class MyThemeModel extends ChangeNotifier{
ThemeData _themedata;
MyThemeModel(bool isActive){
if(isActive == null){
getThemeData;
}
else{
if(isActive){
_themedata = sleepTheme;
}
else{
_themedata = morningTheme;
}
}
}
ThemeData get getThemeData => _themedata;
void setThemeData(ThemeData data){
_themedata = data;
notifyListeners();
}
}
在 main.dart
void main() async{
var isSleepActive;
if(SharedPrefHelper.prefInstance.checkContains(SharedPrefKeys.ISMORNING)){
isSleepActive = SharedPrefHelper.prefInstance.getBool(SharedPrefKeys.ISMORNING);
}
else{
isSleepActive = false;
}
runApp(MultiProvider(
providers: [
ChangeNotifierProvider(
builder: (context) => MyThemeModel(isSleepActive),
)
],
child: MyApp(),
)
);
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: Provider.of<MyThemeModel>(context).getThemeData,
title: 'Theme App',
home: AnimatedSplashScreen(
duration: 3000,
splash: "",
splashTransition: SplashTransition.slideTransition,
pageTransitionType: PageTransitionType.downToUp,
nextScreen: Nav(),
),
debugShowCheckedModeBanner: false,
);
}
為了使用平面按鈕更改主題:
FlatButton(
onPressed: () => myThemeModel.setThemeData(
ThemeData(
bottomNavigationBarTheme: lNavBar,
scaffoldBackgroundColor: Colors.white,
brightness: Brightness.light,
iconTheme: lIcons,
primaryColor: kWhite,
)),
child: Text('Light Theme')),
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