Dragging is interrupted when call setState on onSelect

[kainosk]

When call setState on onSelect callback, my dragging is interrupted.

Maybe I missed something to use this picker correctly or a bug?

👇 Below is a code to reproduce the problem.

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

void main() {
  runApp(const _MyApp());
}

class _MyApp extends StatelessWidget {
  const _MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const _Page(),
    );
  }
}

class _Page extends StatefulWidget {
  const _Page({Key? key}) : super(key: key);
  @override
  State<_Page> createState() => _PageState();
}

class _PageState extends State<_Page> {
  int _selectedIndex = 0;
  final data = ['0', '1', '2', '3', '4', '5', '6'];

  @override
  Widget build(BuildContext context) {
    final selectedTextStyle =
        Theme.of(context).textTheme.bodyText1!.copyWith(color: Colors.orange);
    return Scaffold(
      appBar: AppBar(
        title: const Text('Issue reproduce sample'),
      ),
      body: Center(
        child: Picker(
          adapter: PickerDataAdapter<String>(pickerdata: data),
          selecteds: [_selectedIndex],
          height: 150,
          itemExtent: 28.0,
          hideHeader: true,
          selectedTextStyle: selectedTextStyle,
          onSelect: (picker, _, selectedIndexes) {
            _onItemSelected(selectedIndexes.first);
          },
        ).makePicker(),
      ),
    );
  }

  void _onItemSelected(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }
}

---

When I fix makePicker method like below, I can confirm expected behavior.

// 1. add key argument
Widget makePicker([ThemeData? themeData, bool isModal = false, Key? key]) {
    _maxLevel = adapter.maxLevel;
    adapter.picker = this;
    adapter.initSelects();
    _widget = PickerWidget(
      key: key ?? ValueKey(this), // 2. use key if key is passed
      child:
      _PickerWidget(picker: this, themeData: themeData, isModal: isModal),
      data: this,
    );
    return _widget!;
  }

So, I think setState will create new key ('ValueKey(this)') every time. And maybe this is unintentional code...?

Thank you for your great package ❤️

[yangyxd]

I have incorporated your modifications manually.