Returning data from a Stateful Widget in Flutter

Question

I have previously posted about this problem I am still facing Which is to return data from a Stateful widget back to a Stateless Widget

The Widget I am using is Dat

Answer 1

For more time saving solution for returning value from another widget and using it, here's an example for Flutter Dropdown:

import 'package:flutter/material.dart';
import 'package:paxi_ride/constant.dart';

class BuildDropdown extends StatefulWidget {
  final ValueChanged onChanged;
  String defaultValue, selectedValue, dropdownHint;
  List itemsList;

  BuildDropdown(
      {Key key,
      this.itemsList,
      this.defaultValue,
      this.dropdownHint,
      this.onChanged})
      : super(key: key);

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

class _BuildDropdownState extends State {
  String _value;

  @override
  Widget build(BuildContext context) {
    return Container(
      // height: 40,
      padding: EdgeInsets.symmetric(horizontal: 16, vertical: 0),
      margin: EdgeInsets.symmetric(horizontal: 16, vertical: 8),
      color: Colors.white,
      child: DropdownButton(
        items: widget.itemsList.map(
          (String value) {
            return new DropdownMenuItem(
              value: value,
              child: new Text(value),
            );
          },
        ).toList(),
        value: _value == null ? widget.defaultValue : _value,
        isExpanded: true,
        onChanged: (String value) {
          setState(() {
            _value = value;
          });
          widget.onChanged(value);
        },
        hint: Text(widget.dropdownHint),
        style: TextStyle(
          fontSize: 14,
          color: brownColorApp,
        ),
        iconEnabledColor: brownColorApp,
        iconSize: 14,
        underline: Container(),
      ),
    );
  }
}

Call this widget from another widget where you want to get selected value like this:

String selectedValue; //class field

BuildDropdown(
          itemsList: ['Option 1','Option 2'],
          defaultValue: 'Option 1',
          dropdownHint: 'Select Required Option',
          onChanged: (value) {
            selectedValue = value;
          },
        ),

Use this value wherever needed, it will be changed as dropdown selection is changed.