在重新启动应用程序进入初始状态
我正在学习颤振，我是新手！ 我在 flutter 中做了一个应用程序，在那个主体里面我放了一个容器。 应用程序也有动态页面，可以动态添加到容器中，所以我使用 list.view Builder， 并通过滚动查看此页面。 但是当应用程序关闭并重新启动时，这些页面消失了！！ 即使在应用程序重新启动后，我也想将这些页面保留在 Container 中！！！ 这是我的代码
import 'package:dynamic_widget/Contact.dart';
import 'package:dynamic_widget/DataBase%20Helper/DataBaseHelper.dart';
import 'package:dynamic_widget/DataBase.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
final DataBaseUnit dataBase = new DataBaseUnit();
void main() {
runApp( MaterialApp(home: HomeScreen()));
}
class HomeScreen extends StatefulWidget {
const HomeScreen({Key key}) : super(key: key);
@override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('HOME'),
actions: [
IconButton(
icon: Icon(Icons.add),
onPressed: () {
setState(() {
addWidget();
});
}),
],
),
body: Container(
// height: 200,
padding: EdgeInsets.all(20),
color: Colors.deepOrange,
child: Column(
children: <Widget>[
Flexible(
child: ListView.builder(
scrollDirection: Axis.horizontal,
itemCount: listWidget.length,
itemBuilder: (_, index) => listWidget[index],
padding: EdgeInsets.symmetric(),
),
),
FloatingActionButton(
child: Icon(Icons.add),
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => ContentScreen()),
);
})
],
),
),
);
}
/////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////
List<Widget> listWidget = [];
// List<DynamicWidget2> listWidget2 = [];
addWidget() async {
listWidget.add(new DynamicWidget());
}
addWidget2() {
listWidget.add(new DynamicWidget2());
}
////////////////////////////////////////////////////////
class DynamicWidget extends StatefulWidget {
@override
_DynamicWidgetState createState() => _DynamicWidgetState();
}
class _DynamicWidgetState extends State<DynamicWidget> {
bool showDialog = false;
TextEditingController RoomName = new TextEditingController();
TextEditingController Code = new TextEditingController();
TextEditingController B1 = new TextEditingController();
TextEditingController B2 = new TextEditingController();
TextEditingController B3 = new TextEditingController();
TextEditingController B4 = new TextEditingController();
String name = "";
String code = "";
String b1 = "";
String b2 = "";
String b3 = "";
String b4 = "";
@override
Widget build(BuildContext context) {
return Container(
alignment: Alignment.center,
width: 400,
padding: EdgeInsets.all(10),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(20),
),
child: Container(
width: 300,
height: 600,
padding: EdgeInsets.all(10),
decoration: BoxDecoration(
boxShadow: [
BoxShadow(
color: Colors.grey.withOpacity(0.3),
spreadRadius: 15,
blurRadius: 12,
offset: Offset(3, 3), // changes position of shadow
),
BoxShadow(
color: Colors.deepOrange[900].withOpacity(1), spreadRadius: 3,
blurRadius: 0,
offset: Offset(-3, -3), // changes position of shadow
),
],
borderRadius: BorderRadius.circular(20),
color: Colors.deepOrange[700],
),
child: SingleChildScrollView(
dragStartBehavior: DragStartBehavior.down,
child: Column(
children: <Widget>[
showDialog == true
? AlertDialog(
content: Column(children: [
TextField(
decoration: InputDecoration(hintText: "Code"),
controller: Code,
),
TextField(
decoration:
InputDecoration(hintText: "Provide Room name"),
controller: RoomName,
),
TextField(
decoration: InputDecoration(
hintText: "Provide BUTTON1 name"),
controller: B1,
),
TextField(
decoration: InputDecoration(
hintText: "Provide BUTTON2 name"),
controller: B2,
),
TextField(
decoration: InputDecoration(
hintText: "Provide BUTTON3 name"),
controller: B3,
),
TextField(
decoration: InputDecoration(
hintText: "Provide BUTTON4 name"),
controller: B4,
),
]),
actions: [
IconButton(
icon: Icon(Icons.add),
onPressed: () {
setState(() async {
showDialog = false;
name = RoomName.text;
code = Code.text;
b1 = B1.text;
b2 = B2.text;
b3 = B3.text;
b4 = B4.text;
var contact = new Contact(
Code: code,
RoomName: name,
Button1: b1,
Button2: b2,
Button3: b3,
Button4: b4,
);
var db = DataBaseHelper();
await db.create(contact);
print('id created ');
});
})
],
)
: Text(''),
FlatButton(
color: Colors.blue,
child: Text(name),
onLongPress: () {
setState(() {
showDialog = true;
});
},
onPressed: () {},
),
SizedBox(
height: 40,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.lightbulb,
color: Colors.yellow,
size: 90,
),
Text(
b1,
textScaleFactor: 1,
)
],
),
),
),
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.lightbulb,
color: Colors.yellow,
size: 90,
),
Text(
b2,
textScaleFactor: 1,
)
],
),
),
),
],
),
SizedBox(
height: 40,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.lightbulb,
color: Colors.yellow,
size: 90,
),
Text(
b3,
textScaleFactor: 1,
)
],
),
),
),
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.lightbulb,
color: Colors.yellow,
size: 90,
),
Text(
b4,
textScaleFactor: 1,
)
],
),
),
),
],
),
SizedBox(
height: 40,
),
Row(
mainAxisAlignment: MainAxisAlignment.spaceAround,
children: [
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.flip_camera_android_rounded,
color: Colors.yellow,
size: 30,
),
],
),
),
),
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.flip_camera_android_rounded,
color: Colors.yellow,
size: 10,
),
],
),
),
),
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.flip_camera_android_rounded,
color: Colors.yellow,
size: 10,
),
],
),
),
),
Flexible(
flex: 1,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(10.0),
),
onLongPress: () {
showDialog = true;
},
onPressed: () {},
color: Colors.deepOrangeAccent[200],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(
Icons.flip_camera_android_rounded,
color: Colors.yellow,
size: 10,
),
],
),
),
),
],
),
],
),
),
));
}
}
////////////////////////////////////////////////////////////
class ContentScreen extends StatefulWidget {
@override
_ContentScreenState createState() => _ContentScreenState();
}
class _ContentScreenState extends State<ContentScreen> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: ListView(
children: [
Container(
color: Colors.blue,
child: FlatButton(
onPressed: () {
setState(() {
var Widget = addWidget();
addWidget();
Navigator.push(context,
MaterialPageRoute(builder: (context) => HomeScreen()));
});
},
child: Icon(Icons.ac_unit)),
),
Container(
color: Colors.red,
child: FlatButton(
onPressed: () {
setState(() {
addWidget2();
Navigator.push(context,
MaterialPageRoute(builder: (context) => HomeScreen()));
});
},
child: Icon(Icons.ac_unit)),
),
Container(
color: Colors.green,
),
Container(
height: 80,
color: Colors.yellow,
),
Container(
height: 80,
color: Colors.brown,
),
],
),
);
}
}
应用重启后又回到初始状态
1 个答案:
答案 0 :(得分：0)
默认情况下，Flutter 不会在应用重新启动时存储任何应用状态。解决您的问题的一种解决方案是使用 shared_preferences 颤振插件。使用它，您可以跨应用重新启动存储数据（在您的情况下应该显示哪些页面），在打开应用时再次获取它并相应地构建您的用户界面。
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