问题描述
我正在创建一个多步骤帐户设置页面并遇到一个问题，当我添加数据后滚动到下一页时，它会在上一页上删除它。 换句话说，我无法保存我的数据。
我在谷歌上搜索了很多，知道解决方案是设置状态和键，但我不确定如何在我的情况下实现它们。
main.dart
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:Flutter/material.dart';
import 'package:vibe/AllScreens/LoginPage.dart';
import 'package:vibe/AllScreens/MainScreen.dart';
import 'package:vibe/AllScreens/RegistrationScreen.dart';
import 'package:vibe/AllScreens/RessetPassword.dart';
import 'package:vibe/AllScreens/UserInfo.dart';
import 'package:vibe/AllScreens/UserInfo2.dart';
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
}
//may be of every class?
DatabaseReference userRef = FirebaseDatabase.instance.reference().child("users");
//Create second table here for truck drivera data
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData(
//font family can be changed to a ny font
fontFamily: "Brand Bold",primarySwatch: Colors.blue,visualDensity: VisualDensity.adaptivePlatformDensity
),//initialRoute: LoginScreen.idScreen,home: UserInfo2(),debugShowCheckedModeBanner: false
);
}
}
UserInfo2.dart
import 'package:dropdownfield/dropdownfield.dart';
import 'package:Flutter/material.dart';
import 'package:vibe/constants.dart';
import 'package:Flutter_swiper/Flutter_swiper.dart';
import 'package:vibe/data.dart';
class UserInfo2 extends StatefulWidget {
static const String idScreen = "userInfo2";
@override
_UserInfo2 createState() => _UserInfo2();
}
SwiperController j=SwiperController();
class _UserInfo2 extends State<UserInfo2> {
// var pages=[];
int tempsex=0;
var pages=[];
@override
void initState(){
super.initState();
pages = [
[Gender(),1],[Gender(),];
}
final _key = GlobalKey();
bool enabled=false;
@override
Widget build(BuildContext context) {
var _onpressed = null;
if (enabled==true){
_onpressed = (){
print("enable");
};
}
return Scaffold(
backgroundColor: gradientEndColor,body: SingleChildScrollView(
child: Container(
decoration: Boxdecoration(
gradient: LinearGradient(
colors: [gradientStartColor,gradientEndColor],begin: Alignment.topCenter,end: Alignment.bottomCenter,stops: [0.3,0.7]),),child: SafeArea(
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,children: <Widget>[
Padding(
padding: const EdgeInsets.all(32.0),child: Column(
children: <Widget>[
Text(
'Let us kNow a bit more about you!',style: TextStyle(
fontFamily: 'Avenir',fontSize: 30,color: const Color(0xffffffff),fontWeight: FontWeight.w900,textAlign: TextAlign.left,],Container(
height: 600,padding: const EdgeInsets.only(left: 16),child: Swiper(
loop: false,itemCount: 6,//Todo fix this
itemWidth: MediaQuery.of(context).size.width-50,itemHeight: 620,layout: SwiperLayout.STACK,//dots
pagination: SwiperPagination(
builder:
DotSwiperPaginationBuilder(activeSize: 20,space: 6),//page swiper
),//height ans stuff can be changed here
itemBuilder: (context,index) {
return InkWell(
child: Stack(//Everythink in Box
children: <Widget>[
Column(
children: <Widget>[
Card(
elevation: 16,shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(16),color: Colors.white,child: Padding(
padding: const EdgeInsets.only(top: 16.0,bottom: 16.0),child: Column(
crossAxisAlignment:
CrossAxisAlignment.start,children: <Widget>[
pages[index][0],//SizedBox(height: 40),//NUMBER INDEX
Positioned(
right: 10,bottom: 45,child: Text(
pages[index][1].toString(),style: TextStyle(
fontFamily: 'Avenir',fontSize: 160,color: primaryTextColor.withOpacity(0.08),);
},//control: SwiperControl(),Column(
children: [
RaisedButton(
color: gradientStartColor,textColor: Colors.white,// focusElevation: 12,child: Container(
height: 50.0,//alignment: Alignment.center,child: Center(
child: Text(
"Finish!",style: TextStyle(fontSize: 18.0,fontFamily: "Brand-Regular"),shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(24),onpressed: _onpressed,)
],)
);
}
}
//===============================================
//===============================================================
class Gender extends StatefulWidget {
//const Gender({Key key}) : super(key: key);
//List<int> _selectedItems = List<int>();
@override
_GenderState createState() => _GenderState();
}
class _GenderState extends State<Gender> {
@override
void initState() {
_selectedItems.add(gender);
selected=true;
print(gender);
}
List<String> genders=["Male","Female","Transgender Male","Transgender Female","Other"];
int gender;
List<int> _selectedItems = List<int>();
bool selected=false;
@override
Widget build(BuildContext context) {
return Container(
height: 500,child: Container(
child: Column(
children: [
Text(
"Gender",style: TextStyle(
fontFamily: 'Avenir',color: Colors.black54,SizedBox(height: 8,Text(
"choose one",fontSize: 20,fontWeight: FontWeight.normal,SizedBox(
height: 400,child: ListView.builder(
itemCount: genders.length,itemBuilder: (context,index){
return
Padding(
padding: const EdgeInsets.all(4.0),child: Container(
decoration: Boxdecoration(
borderRadius: BorderRadius.circular(16),color: (_selectedItems.contains(index)) ? Colors.greenAccent.withOpacity(0.5) : Colors.transparent,// border: Border.all(color: (_selectedItems.contains(index)) ? gradientStartColor.withOpacity(0.5) : Colors.transparent,border: Border.all(color: gradientStartColor.withOpacity(0.5) ),BoxShadow: [(_selectedItems.contains(index)) ? BoxShadow(
color: Colors.grey.withOpacity(0.5),spreadRadius: 2,blurRadius: 7,offset: Offset(0,3),// changes position of shadow
):BoxShadow(color: Colors.transparent)
]
),child: ListTile(
onTap: (){
setState(() {
if(selected && _selectedItems.contains(index)) {
_selectedItems.removeWhere((val) =>
val == index);
selected = false;
gender=null;
}else if(!selected && !_selectedItems.contains(index)){
gender=index;
_selectedItems.add(gender);
selected=true;
}
else{
_selectedItems.removeWhere((val) =>
val == _selectedItems[0]);
gender=index;
_selectedItems.add(gender);
}
});
print(gender);
},title:Text( genders[index].toString(),textAlign: TextAlign.center,)
),);
},);
}
}
Widget smth(BuildContext context){
return Container(
child: Text(
"huy"
),);
}
解决方法
从您提供的代码中不清楚您是如何在页面之间导航的。
一般来说，在导航时保存页面状态有以下两种方法：
- 索引堆栈小部件：https://api.flutter.dev/flutter/widgets/IndexedStack-class.html
- AutomaticKeepAliveClientMixin：https://api.flutter.dev/flutter/widgets/AutomaticKeepAliveClientMixin-mixin.html
请参考上一篇。与底部导航和保存页面状态相关的问题，以便更清晰。同样的原则适用于您想做的事情：
How to preserve widget states in flutter,when navigating using BottomNavigationBar?