我正在嘗試實作一個功能，其中用戶在一個螢屏上提供輸入并且資料存盤在本地（共享首選項），一旦用戶回到另一個螢屏或彈回，資料應該立即更新到該螢屏上一個螢屏。目前正在發生的事情是，只有當我導航到另一個螢屏并導航回該螢屏時，資料才會更新。
SharedPreferences
import 'package:shared_preferences/shared_preferences.dart';
class UserSimplePreferences {
static late SharedPreferences _preferences;
static const _name = 'name';
static const _age = 'age';
static const _gender = 'gender';
static const _church = 'church';
static const _churchCity = 'churchCity';
static const _churchState = 'churchState';
static Future init() async =>
_preferences = await SharedPreferences.getInstance();
static Future setName(String name) async =>
await _preferences.setString(_name, name);
static String? getName() => _preferences.getString(_name);
static Future setAge(String age) async =>
await _preferences.setString(_age, age);
static String? getAge() => _preferences.getString(_age);
static Future setGender(String gender) async =>
await _preferences.setString(_gender, gender);
static String? getGender() => _preferences.getString(_gender);
static Future setChurch(String church) async =>
await _preferences.setString(_gender, church);
static String? getChurch() => _preferences.getString(_church);
static Future setChurchCity(String churchCity) async =>
await _preferences.setString(_gender, churchCity);
static String? getChurchCity() => _preferences.getString(_churchCity);
static Future setChurchState(String churchState) async =>
await _preferences.setString(_gender, churchState);
static String? getChurchState() => _preferences.getString(_churchState);
}
Register(Here the data should be updated)
class Register extends StatefulWidget {
@override
_RegisterState createState() => _RegisterState();
}
class _RegisterState extends State<Register> {
late String? name = UserSimplePreferences.getName();
// final user = UserSimplePreferences.getUser();
@override
void initState() {
// TODO: implement initState
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body:Container(
child: Column(
children: [
Card(
child: Text(name??''),
),
Card(
child: Text(name??''),
),
Card(
child: Text(name??''),
)
],
)
),
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.indigo[900],
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (_) {
return AddUser(idUser: '',);
}),
);
},
child: Icon(Icons.add, color: Colors.white),
),
);
}
}
AddUser(where user provides input)
class AddUser extends StatefulWidget {
final String? idUser;
const AddUser({required this.idUser});
@override
_AddUserState createState() => _AddUserState();
}
class _AddUserState extends State<AddUser> {
final formKey = GlobalKey<FormState>();
String name = '';
String age = '';
String gender= '';
String church= '';
String churchCity= '';
String churchState= '';
@override
void initState() {
super.initState();
// name = UserSimplePreferences.getName() ?? '';
// age = UserSimplePreferences.getAge() ?? '';
// gender = UserSimplePreferences.getGender() ?? '';
// church = UserSimplePreferences.getChurch() ?? '';
// churchCity = UserSimplePreferences.getChurchCity() ?? '';
// churchState = UserSimplePreferences.getChurchState() ?? '';
}
@override
Widget build(BuildContext context) => Scaffold(
appBar: AppBar(
automaticallyImplyLeading: false,
title : Text('Please Enter Your Details',textAlign: TextAlign.center,)),
body: SafeArea(
child: ListView(
padding: EdgeInsets.all(16),
children: [
buildName(),
const SizedBox(height: 12),
buildAge(),
const SizedBox(height: 12),
buildGender(),
const SizedBox(height: 12),
buildChurch(),
const SizedBox(height: 12),
buildChurchCity(),
const SizedBox(height: 12),
buildChurchState(),
const SizedBox(height: 12),
buildButton(),
],
),
),
);
Widget buildName() =>
buildTitle(
title: 'Name',
child: TextFormField(
initialValue: name,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Your Name',
),
onChanged: (name) => setState(() => this.name = name),
),
);
Widget buildAge() => buildTitle(
title: 'Age',
child: TextFormField(
initialValue: age,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Your Age',
),
onChanged: (age) => setState(() => this.age = age),
),
);
Widget buildGender() => buildTitle(
title: 'Gender',
child: TextFormField(
initialValue: gender,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Your gender(M/F)',
),
onChanged: (gender) => setState(() => this.gender = gender),
),
);
Widget buildChurch() => buildTitle(
title: 'Church',
child: TextFormField(
initialValue: church,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Your church',
),
onChanged: (church) => setState(() => this.church = church),
),
);
Widget buildChurchCity() => buildTitle(
title: 'Church City',
child: TextFormField(
initialValue: churchCity,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Your Church City',
),
onChanged: (churchCity) => setState(() => this.churchCity = churchCity),
),
);
Widget buildChurchState() => buildTitle(
title: 'Church State',
child: TextFormField(
initialValue: churchState,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Your Church State',
),
onChanged: (churchState) => setState(() => this.churchState = churchState),
),
);
Widget buildButton() => ButtonWidget(
text: 'Save',
onClicked: () async {
await UserSimplePreferences.setName(name);
await UserSimplePreferences.setAge(age);
await UserSimplePreferences.setGender(gender);
await UserSimplePreferences.setChurch(church);
await UserSimplePreferences.setChurchCity(churchCity);
await UserSimplePreferences.setChurchState(churchState);
Navigator.pop(context);
});
Widget buildTitle({
required String title,
required Widget child,
}) =>
Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
Text(
title,
style: TextStyle(fontWeight: FontWeight.bold, fontSize: 18),
),
const SizedBox(height: 8),
child,
],
);
}
uj5u.com熱心網友回復：
您第一次構建視圖，然后加載資料。沒有關于力的視圖互動，setState所以這個視圖沒有任何改變。你現在能做什么？你有兩種方法：
setState在加載變數后運行shared_pref- 用于
FutureBuilder在加載資料之前和之后渲染另一個小部件，我建議使用第二個選項
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/497269.html
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