I want to save the first initialized value in a TextFormField in a CupertinoPicker in Flutter

Question

I want to save the first initialized value in a TextFormField in a CupertinoPicker. I've searched on Google and various forums, but it seems that I couldn't find a way to set the initial value as I want in CupertinoPicker. Is there really no way to do this?

it's front part

Container(
                                            child: HeightPicker(
                                              onSelectedItemChanged:
                                                  (selectedHeight) {
                                                // 선택 항목이 변경될 때의 동작
                                                // _heightController.text =
                                                //     '$selectedHeight cm';
                                                print(
                                                    'front : $selectedHeight cm');
                                                _heightController.text =
                                                    (selectedHeight).toString();
                                              },
                                            ),
                                          )

it's the widget code.

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

class HeightPicker extends StatefulWidget {
  final ValueChanged<int> onSelectedItemChanged;

  // required this.onSelectedItemChanged,
  const HeightPicker({
    Key? key,
    required this.onSelectedItemChanged,
  }) : super(key: key);

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

class _HeightPickerState extends State<HeightPicker> {
  final ScrollController scrollController = ScrollController();
  late int _selected;
  // late int _onClicked;

  @override
  void initState() {
    super.initState();
    _selected = 20; // 초기 선택 항목
    // _onClicked = 15;
  }

  @override
  Widget build(BuildContext context) {
    return CupertinoPicker(
      itemExtent: 30,
      diameterRatio: 1,
      scrollController: FixedExtentScrollController(
        initialItem: _selected,
      ),
      children: List<Widget>.generate(45, (index) {
        // 150 ~ 190의 값
        int value = 150 + index;
        return Text('$value cm');
      }),
      onSelectedItemChanged: (int value) {
        setState(() {
          _selected = value;
          print('scrolling : $value');
          widget.onSelectedItemChanged(150 + value);
          // _heightController.text = (150 + value).toString();
        });
      },
    );
  }
}

I have tried various methods, but I have failed to retrieve the specified initial value into the text field. However, I am slowly digesting the situation while reviewing the reference 'Link'. Still, I wonder if there might be a solution.!

Answer 1

You can await for the modal to pop and check if the value has stayed the same. In that case you can reset to default/initial value (or whatever value you want). Example:

ElevatedButton(
  onPressed: () async {
    final previousValue = date;
    await showCupertinoModalPopup<void>(
      context: context,
      builder: (_) {
        final size = MediaQuery.of(context).size;
        return Container(
          decoration: const BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.only(
              topLeft: Radius.circular(12),
              topRight: Radius.circular(12),
            ),
          ),
          height: size.height * 0.27,
          child: CupertinoDatePicker(
            mode: CupertinoDatePickerMode.date,
            onDateTimeChanged: (value) {
              date = value;
              setState(() {});
            },
          ),
        );
      },
    );
    // no value was selected
    if (previousValue == date) {
      //back to default value which is DateTime.now() if initialDateTime is not provided to CupertinoDatePicker
      setState(() {
        final now = DateTime.now();
        date = DateTime(now.year, now.month, now.day);
      });
    }
  },
  child: const Text('Show Date Picker'),
),