Question

我想制作一个奖励积分应用程序，因为我使用了随机函数。

问题是我不知道如何将此号码添加到先前的号码。得到总分。

这是我想要在此处求和的结果。

修改后，我收到此错误

这是我的奖励应用程序的完整代码

rewards.dart

import 'dart:async';
import 'package:fid786/Services/CardScreen.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:fid786/styles.dart';
import 'package:fid786/Services/ClasNumber.dart';
class RewardsScreen extends StatefulWidget {
@override
_RewardsScreenState createState() => _RewardsScreenState();
}
class _RewardsScreenState extends State<RewardsScreen> {
@override
void initState() {
super.initState();
startTimer();
}
startTimer() async{
  var duration=Duration(seconds: 4);
  return Timer(duration,route);
}
route(){
  Navigator.pushReplacement(context, MaterialPageRoute(builder: 
(context)=>CardScreen()));
}                       
@override
Widget build(BuildContext context) {
return Scaffold(
  resizeToAvoidBottomPadding: false,
  body: AnnotatedRegion<SystemUiOverlayStyle>(
    value: SystemUiOverlayStyle.light,
    child: Container(
    height: MediaQuery.of(context).size.height,
    width: MediaQuery.of(context).size.width,
      decoration: BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topCenter,
          end: Alignment.bottomCenter,
          stops: [0.1, 0.4, 0.7, 0.9],
          colors: [
            Color(0xFF3594DD),
            Color(0xFF4563DB),
            Color(0xFF5036D5),
            Color(0xFF5B16D0),
          ],
        ),
      ),
      child: Padding(
        padding: EdgeInsets.only(top:80),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
             Expanded(
                    flex: 8,
            child:Container(
              height: MediaQuery.of(context).size.height,
              width: MediaQuery.of(context).size.width,
              //height: 600.0,
              child: PageView(
                children: <Widget>[
                 
                    Padding(
                     padding: EdgeInsets.symmetric(horizontal: 2),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: <Widget>[
                        Center(
                          child: ClipRRect(
                          borderRadius: BorderRadius.circular(50.0),
                          child: Image(
                            image: AssetImage(
                              'assets/images/congrats.gif',
                            ),
                            height: 300.0,
                            width: 300.0,
                            fit: BoxFit.fill,
                          ),
                          ),
                        ),
                        SizedBox(height: 30.0),
                        Text(
                          ' Congratulations, You have Got',
                           style: kTitleStyle,
                        ),
                        SizedBox(height: 20.0),
                        Center(
                        child:Text(
                          ClassName.generateRandomNumber().toString(),   
                          style: TextStyle(color: Colors.greenAccent,
                          fontWeight: FontWeight.bold,
                          fontSize: 50)),
                      ),
                     SizedBox(height: 10.0),

                        Center(
                        child:Text(
                          '  Points ',
                          style: kTitleStyle,
                        ),
                        ),
                         SizedBox(height: 50.0),
                        
                        Center(
                        child:Text(
                          'Earn More Points and Win Prizes ',
                          style:
                          TextStyle(
                          color: Colors.yellowAccent,
                          fontWeight: FontWeight.bold,
                          fontSize: 16,
                          fontFamily: 'muso',
                          decoration: TextDecoration.underline),
                        ),
                        ),
                      ],
                    ),
                  ), 
                ],
              ),
            ),
            ),
          ],
        ),
      ),
    ),
  ),
      
);
}
}

文件CardScreen.dart

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
import 'package:fid786/ScanQR/Card_Scanner.dart';
import 'package:fid786/Authentification/LogInScreen.dart';
import 'package:fid786/Services/ClasNumber.dart';
class CardScreen extends StatefulWidget {
@override
_CardScreenState createState()=>_CardScreenState();

}
class _CardScreenState extends State<CardScreen>{
FirebaseAuth auth=FirebaseAuth.instance;
Future<void>logOut() async{
FirebaseUser user=auth.signOut() as FirebaseUser; 
return user; 
}
@override
void initState() {
super.initState();
}
int points = 0;
int generateNumber() {
                       
                      int newPoints = ClassName.generateRandomNumber();
setState(() {
points += newPoints;
});
return points;
                        }
@override
Widget build(BuildContext context){

return Scaffold(
  backgroundColor:Color(0xffffffff),
  appBar:AppBar(
    backgroundColor: Colors.greenAccent,
    title:Text("Loyalty Points"),
    actions: <Widget>[
      SizedBox(width:1.0),
      FlatButton.icon(onPressed: (){
        logOut();
        Navigator.pushReplacement(context, MaterialPageRoute(builder: 
   (BuildContext context)=>LogInScreen()));
      },
      icon: Icon(Icons.shopping_cart,size: 40.0,color: 
   Colors.pinkAccent,), label: Text("Log Out",style: TextStyle(color: 
   Colors.pinkAccent),))
   ],
   ),
    body: StreamBuilder(
      stream:Firestore.instance.collection('screen').snapshots(),
      builder:(context,snapshot){
          if(!snapshot.hasData) return Text('');
          
    return Column(
    children: <Widget>[
        Padding(
          
                    padding: EdgeInsets.only(left: 8.0, right: 8.0,top: 
    40.0),
                    child: Container(
                      width: MediaQuery.of(context).size.width,
                      height: 80.0,
                      child: Padding(
                        padding: EdgeInsets.only(top: 8.0, bottom: 8.0),
                        child: Material(
                          shape: Border.all(width: 2.0, color: 
    Colors.blueAccent),
                          color: Colors.white,
                          elevation: 18.0,
                          shadowColor: Color(0x802196F3),
                         
                          child: Center(
                            child: Padding(
                              padding: EdgeInsets.all(5.0),
                              child: Row(
                               // mainAxisAlignment:
                                 //   MainAxisAlignment.spaceBetween,
                                children: <Widget>[       
                                  Text(
                                    snapshot.data.documents[0]['player'],
                                    style: TextStyle(
                                        color: Colors.greenAccent,
                                        fontWeight: FontWeight.bold,
                                        fontSize: 18.0),
                                  ),        
                                // mainAxisAlignment:
                                 //   MainAxisAlignment.spaceBetween,
                                 SizedBox(width:175),
                                  Column(
                                    
                                    mainAxisAlignment:
                                        MainAxisAlignment.center,
                                    children: <Widget>[
                                         
                        Text(
                          generateNumber().toString(),
                          style: TextStyle(color: Colors.greenAccent,
                          fontWeight: FontWeight.bold,
                          fontSize: 25)),
                      
                                      Text(
                                        'Points',
                                        style: TextStyle(
                                            color: Colors.pinkAccent,
                                            fontWeight: FontWeight.bold,
                                            fontSize: 16.0,
                                            fontFamily: 'muso'),
                                      ),
                                    ],
                                  )
                                ],
                              ),
                            ),
                          ),
                        ),
                      ),
                    ),
        ),
                       
    ],
  );
      }
    ), 
        floatingActionButton: FloatingActionButton(
    backgroundColor: Color(0xFFFA7397),
    child: Icon(
      FontAwesomeIcons.listUl,
      color: Color(0xFFFDDE42),
    ),
    onPressed: () {
      Navigator.push(
        context,
        MaterialPageRoute(
            builder: (context) => HomePage(), fullscreenDialog: true),
      );
    },
  )
);
}
}

文件ClasNumber.dart

import 'dart:math';

class ClassName{

static int generateRandomNumber() {
List<int> pointValue = [5,6,7,8,10,15];
return pointValue[new Random().nextInt(pointValue.length)];
}
}

Answer 1

您可以使用setState()函数来实现此目的。

int points = 0;
int newPoints = generateRandomNumber();
setState(() {
  points += newPoints
});

如果要全局存储总积分值，则应查看shared preferences包。

能够全局使用该函数的最佳方法是将其包装在单独的全局类中。

class ClassName{
  static int generateRandomNumber() {
    return pointValue[new Random().nextInt(pointValue.length)];
  }
}

然后在其他课程中，您可以这样调用：

ClassName.generateRandomNumber();

您得到的错误是由于在build（）函数外部调用setState引起的。像这样将生成编号函数移到构建函数中

@override
Widget build(BuildContext context){
int generateNumber() {
 int newPoints = ClassName.generateRandomNumber();
 setState(() {
   points += newPoints;
 });
 return points;
}

增加奖励点数

1 个答案: