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Simple Random Num Gen flutter-dart

I am trying to create random numbers after clicking the button. it works in the console but not on the UI. Need help with this. I am missing something

    import 'dart:math';
import 'package:flutter/material.dart';

class RandomNum extends StatefulWidget {
  const RandomNum({super.key});

  @override
  State<RandomNum> createState() => _RandomNumState();
}

Random random = Random();
int randomNumber = random.nextInt(10);

class _RandomNumState extends State<RandomNum> {
  void randomNumberFunction() {
    setState(() {
      Random random = Random();
      int randomNumber = random.nextInt(10);
      print(randomNumber);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Column(
        children: [
          Text(randomNumber.toString()),
          ElevatedButton(onPressed: randomNumberFunction, child: Text('Guess'))
        ],
      ),
    );
  }
}
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2

Answers


  1. 0

    You are recreating new variable, remove the int

     void randomNumberFunction() {
    setState(() {
      Random random = Random();
      randomNumber = random.nextInt(10);
      print(randomNumber);
    });
  }

    also you can use initState to set initial number instead of global and use the same random instance to generate number inside the function rest of the time.

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  2. 0

    You have globally initialize the variables and then again in your setState method, remove those and define it within the class.

    Here’s your updated code:

    import 'dart:math';
import 'package:flutter/material.dart';

class RandomNum extends StatefulWidget {
  const RandomNum({super.key});

  @override
  State<RandomNum> createState() => _RandomNumState();
}

class _RandomNumState extends State<RandomNum> {
  Random random = Random();
  int randomNumber = 0;

  void randomNumberFunction() {
    setState(() {
      randomNumber = random.nextInt(10);
      print(randomNumber);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Column(
        children: [
          Text('$randomNumber'),
          ElevatedButton(onPressed: randomNumberFunction, child: Text('Guess'))
        ],
      ),
    );
  }
}
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