Flutter：跨多个屏幕发送数据

我有3个小部件MyApp Widget，Home Widget和Sliver Appbar Widget，它们相互连接。示例 MyApp小部件-> 家庭小部件-> SliverAppbar小部件。

我的问题是，如何将数据从我的应用程序小部件直接传递到 SliverAppBar小部件？

我发现我认为可以解决我的情况的Inherited Widget。但是我很迷糊地使用此小部件。

我已经尝试将Inherited Widget用作此类文档：

MyApp小部件

class SettingsApp extends InheritedWidget {
SettingsApp({Key key,this.isDarkMode = false,Widget child})
: super(key: key,child: child);
final bool isDarkMode;
static SettingsApp of(BuildContext context) {
return (context.dependOnInheritedWidgetOfExactType());
}
@override
bool updateShouldNotify(SettingsApp oldWidget) {
return true;
}
}


SliverAppBar小部件

class SliverAppBarCustom extends StatelessWidget {
final Box detbBox = Hive.box("debt_box");
final UserModelHive userModelHive = Hive.box("user_box").get("userSession");
@override
Widget build(BuildContext context) {
final isDarkMode =
context.dependOnInheritedWidgetOfExactType().isDarkMode;
print(isDarkMode.toString());
var mediaQuery = MediaQuery.of(context);
var textTheme = Theme.of(context).textTheme;
return Text(isDarkMode.toString());
}
}


但是我得到这个错误：

日志

The following NoSuchMethodError was thrown building SliverAppBarCustom(dirty):
The getter 'isDarkMode' was called on null.
Receiver: null
Tried calling: isDarkMode


使用ScopedModel

import 'package:flutter/material.dart';
import 'package:scoped_model/scoped_model.dart';
void main() => runApp(MyApp());
class SettingsModel extends Model {
bool _isDarkMode;
SettingsModel({bool isDarkMode}) : _isDarkMode = isDarkMode ?? false;
bool get isDarkModel => _isDarkMode;
set isDarkModel(bool value) {
_isDarkMode = value;
notifyListeners();
}
void switchTheme() {
_isDarkMode = !_isDarkMode;
notifyListeners();
}
static SettingsModel of(BuildContext context) {
return ScopedModel.of(context);
}
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return ScopedModel(
model: SettingsModel(isDarkMode: true),child: MaterialApp(
home: InitPage(),),);
}
}
class InitPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text("Init Page")),body: SizedBox.expand(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,children: [
ScopedModelDescendant(
builder: (context,child,model) {
return Text('Is Dark Mode: ${model.isDarkModel}');
},RaisedButton(
child: Text("Next Page"),onPressed: () {
Navigator.push(
context,MaterialPageRoute(
builder: (context) => SecondPage(),);
},],);
}
}
class SecondPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Second Page"),RaisedButton(
child: Text("Switch Theme"),onPressed: SettingsModel.of(context).switchTheme,);
}
}


重要提示：没有_isDarkModel的情况下，您不应更改notifyListeners()。如果这样做，则UI可能不会更新。