CODEWITHSUNDEEP
flutterdart
nwfly
nwfly

Reputation: 1

type 'Future<dynamic>' is not a subtype of type 'int'

I'm new on flutter. I just wanted to store best score value. I tried to use Shared Preferences but i got an error.

import 'package:shared_preferences/shared_preferences.dart';

int best;

setBest(int n) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setInt('best', n);
}

getBest() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  int intValue = prefs.getInt('best');
  if (intValue == null) {
    return 0;
  }
  return intValue;
}

I call this dart file an another dart file
'import .... as x'
This pages shows to the user their current score and best

int best = x.getBest();

@override
  void initState() {
    super.initState();
    if (score > best) {
      best = score;
      x.setBest(score);
    }
  }

error message

Exception caught by widgets library    
The following _TypeError was thrown building Builder:
type 'Future<dynamic>' is not a subtype of type 'int'
The relevant error-causing widget was MaterialApp lib\main.dart:9
When the exception was thrown, this was the stack
#0 new _QuizResultState  package:quiz_game/pages/quiz_result.dart:16
#1 QuizResult.createState package:quiz_game/pages/quiz_result.dart:12
#2 new StatefulElement package:flutter/…/widgets/framework.dart:4591
#3 StatefulWidget.createElement package:flutter/…/widgets/framework.dart:894
Normal element mounting (115 frames)

Upvotes: 0

Views: 4082

Answers (1)

Rocigno Medeiros
Rocigno Medeiros

Reputation: 171

When you put async in a method, this method will return a Future<dynamic> object, so in second block of code you try to put a future inside a int: 

int best = x.getBest();

To solve this I suggest:

Future<int> best = x.getBest();

@override
void initState() async {
  super.initState();
  if (score > await best) {
    best = Future.sync(score);
    x.setBest(score);
  }
}

Upvotes: 1

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