Flutter: setState in TextButton not working

Question

Dice image not changing on onPress
setState not setting dice image for random number

child: Image.asset('images/dice$leftDiceNumber.png'), not working but
child: Image.asset('images/dice2.png'), is working that means hard code is working

var leftDiceNumber = 3; getting only dice3.png as i initialize it for leftDiceNumber

Please help for getting random image when onPress

No errors in App

class DicePage extends StatefulWidget {
  const DicePage({Key? key}) : super(key: key);

  @override
  _DicePageState createState() => _DicePageState();
}

class _DicePageState extends State<DicePage> {
  @override
  Widget build(BuildContext context) {
    var leftDiceNumber = 3;
    return Center(
      child: Row(
        children: [
          Expanded(
            child: TextButton(
              onPressed: () {
                setState(() {   
                  leftDiceNumber = Random().nextInt(6) + 1;
                  print(leftDiceNumber); // getting value in console
                });
              },
              child: Image.asset('images/dice$leftDiceNumber.png'),  
                      //child: Image.asset('images/dice1.png'), // ( works )
            ),),],
      ),);}}

Heck Codes · Accepted Answer · 2022-02-07 13:50:46Z

5

That is because every time you call setState() it calls the build method, and you have defined leftDiceNumber = 3 inside the build method. So even though the setState() changes the value it again gets set to 3.

Solution: Move var leftDiceNumber = 3; outside the build method.

class _DicePageState extends State<DicePage> {
  var leftDiceNumber = 3;
  
@override
  Widget build(BuildContext context) {
    return YourWidget();
  }
}

answered Feb 7, 2022 at 13:50

Heck Codes

1611 silver badge7 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

FrancescoPenasa Over a year ago

You should add the initState method and the solution is perfect

Heck Codes Over a year ago

If we can initialize variables without doing the following wouldn't it make it simpler? late variableName; and then initState(){variableName = value;} I'm new to flutter. I'm guessing that using initState() is a good practice even if it is for a simple variable like this. Please enlighten me.

Collectives™ on Stack Overflow

Flutter: setState in TextButton not working

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related