Why variable value is not refreshing in flutter?

Question

The variable value is not refreshing in flutter(which I created outside the class). The following way I have added.So in button press am setting different value. So if I come back to that screen again it is not showing 1. May I know why it is happening?

int _currVal = 1;

class AskFragment extends StatefulWidget {
  static const String routeName = "//";
  static const
  int currState = -1;

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

variables change state inside a StatefulWidget, if you want to change that value, use the method setState(). You're using a global variable that way and you won't get the updated value when changed. — Mariano Zorrilla
– Mariano Zorrilla, Commented Feb 18, 2020 at 16:35
@MarianoZorrilla yeah it is global value only. Am using an Alert dialog in that am setting the value. Am getting the value. But the problem is what ever I got the last value it is remains state. if I come back to the particular screen — Sunisha Guptan
– Sunisha Guptan, Commented Feb 18, 2020 at 16:40
initialize the value inside the class and update the value in setState((){}); :- read this document :- api.flutter.dev/flutter/widgets/StatefulWidget-class.html — Yogesh Chawla
– Yogesh Chawla, Commented Feb 18, 2020 at 17:12

Yogesh Chawla · Accepted Answer · 2020-02-19 06:26:51Z

5

To update the values, use Stateful Widget and initialise values inside that Widget only, for any updates in the values of variables mention that in setState((){}) method to notify the change in the values.

See this for documentation of stateful widgets

See this for documentation of setState((){}) method

setState(() { _myVariable = newValue });

Note:- Never initialise changing values in build method they will not get updated instead they will be reinitialised with same values again and again

answered Feb 19, 2020 at 6:26

Yogesh Chawla

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