ahmedlsayed9 / dropdown_button2 Goto Github PK

flutter: Null check operator used on a null value
flutter: 
#0      DropdownButton2State.didChangeMetrics (package:dropdown_button2/dropdown_button2.dart:1544:20)
#1      WidgetsBinding.handleMetricsChanged (package:flutter/src/widgets/binding.dart:570:16)
#2      _rootRun (dart:async/zone.dart:1426:13)
#3      _CustomZone.run (dart:async/zone.dart:1328:19)
#4      _CustomZone.runGuarded (dart:async/zone.dart:1236:7)
#5      _invoke (dart:ui/hooks.dart:151:10)
#6      PlatformDispatcher._updateWindowMetrics (dart:ui/platform_dispatcher.dart:236:5)
#7      _updateWindowMetrics (dart:ui/hooks.dart:33:31)

/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:172:20: Error: Type 'ShortcutActivator' not found.
  static const Map<ShortcutActivator, Intent> _webShortcuts =
                   ^^^^^^^^^^^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:173:8: Error: 'ShortcutActivator' isn't a type.
      <ShortcutActivator, Intent>{
       ^^^^^^^^^^^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:176:5: Error: Method not found: 'SingleActivator'.
    SingleActivator(LogicalKeyboardKey.arrowDown):

    ^^^^^^^^^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:178:5: Error: Method not found: 'SingleActivator'.

    SingleActivator(LogicalKeyboardKey.arrowUp):
    ^^^^^^^^^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:172:20: Error: 'ShortcutActivator' isn't a type.
  static const Map<ShortcutActivator, Intent> _webShortcuts =
                   ^^^^^^^^^^^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:222:26: Error: The getter 'enabled' isn't defined for the class 'DropdownMenuItem<T>'.
- 'DropdownMenuItem' is from 'package:flutter/src/material/dropdown.dart' ('/C:/Installs/flutter_windows_1.22.2-stable/flutter/packages/flutter/lib/src/material/dropdown.dart').
package:flutter/…/material/dropdown.dart:1
Try correcting the name to the name of an existing getter, or defining a getter or field named 'enabled'.
    if (dropdownMenuItem.enabled) {

                         ^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:233:36: Error: The getter 'enabled' isn't defined for the class 'DropdownMenuItem<T>'.
- 'DropdownMenuItem' is from 'package:flutter/src/material/dropdown.dart' ('/C:/Installs/flutter_windows_1.22.2-stable/flutter/packages/flutter/lib/src/material/dropdown.dart').
package:flutter/…/material/dropdown.dart:1

Try correcting the name to the name of an existing getter, or defining a getter or field named 'enabled'.
    if (kIsWeb && dropdownMenuItem.enabled) {
                                   ^^^^^^^
/C:/Installs/flutter_windows_1.22.2-stable/flutter/.pub-cache/hosted/pub.dartlang.org/dropdown_button2-1.0.7/lib/dropdown_button2.dart:1314:26: Error: The getter 'enabled' isn't defined for the class 'DropdownMenuItem<T>'.
- 'DropdownMenuItem' is from 'package:flutter/src/material/dropdown.dart' ('/C:/Installs/flutter_windows_1.22.2-stable/flutter/packages/flutter/lib/src/material/dropdown.dart').
package:flutter/…/material/dropdown.dart:1
Try correcting the name to the name of an existing getter, or defining a getter or field named 'enabled'.
                    item.enabled && item.value == widget.value)

                         ^^^^^^^

[√] Flutter (Channel stable, 2.2.3, on Microsoft Windows [Version 10.0.19043.1415], locale en-IN)
    • Flutter version 2.2.3 at C:\Installs\flutter_windows_1.22.2-stable\flutter
    • Framework revision f4abaa0735 (6 months ago), 2021-07-01 12:46:11 -0700
    • Engine revision 241c87ad80
    • Dart version 2.13.4

[√] Android toolchain - develop for Android devices (Android SDK version 30.0.2)
    • Android SDK at C:\Users\kohli\AppData\Local\Android\sdk
    • Platform android-30, build-tools 30.0.2
    • Java binary at: C:\Program Files\Android\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)
    • All Android licenses accepted.

[√] Chrome - develop for the web
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Android Studio (version 4.1.0)
    • Android Studio at C:\Program Files\Android\Android Studio
    • Flutter plugin can be installed from:
       https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
       https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b01)

[√] IntelliJ IDEA Community Edition (version 2020.3)
    • IntelliJ at C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.3.2
    • Flutter plugin can be installed from:
       https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
       https://plugins.jetbrains.com/plugin/6351-dart

[√] VS Code (version 1.63.2)
    • VS Code at C:\Users\kohli\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension version 3.29.0

[√] Connected device (3 available)
    • sdk gphone x86 (mobile) • emulator-5554 • android-x86    • Android 11 (API 30) (emulator)
    • Chrome (web)            • chrome        • web-javascript • Google Chrome 96.0.4664.110
    • Edge (web)              • edge          • web-javascript • Microsoft Edge 96.0.1054.34

• No issues found!

Scaffold
  SingleChildScrollView
    Column
      Padding
        DropdownButtonFormField2

Padding(
	padding: const EdgeInsets.fromLTRB(40, 20, 40, 20),
	child: DropdownButtonFormField2(
	  decoration: InputDecoration(
	    //Add isDense true and zero Padding.
	    //Add Horizontal padding using buttonPadding and Vertical padding by increasing buttonHeight instead of add Padding here so that The whole TextField Button become clickable, and also the dropdown menu open under The whole TextField Button.
	    isDense: true,
	    contentPadding: EdgeInsets.zero,
	    border: OutlineInputBorder(
	      borderRadius: BorderRadius.circular(15),
	    ),
	    //Add more decoration as you want here
	    //Add label If you want but add hint outside the decoration to be aligned in the button perfectly.
	  ),
	  isExpanded: true,
	  value: selectedCountry,
	  icon: Icon(
	    Icons.arrow_drop_down,
	    color: Colors.white,
	  ),
	  iconSize: 30,
	  buttonHeight: 48,
	  buttonPadding:
	      const EdgeInsets.only(left: 20, right: 10),
	  dropdownDecoration: BoxDecoration(
	    borderRadius: BorderRadius.circular(15),
	  ),
	  items: countries.map((CountryItem country) {
	    return DropdownMenuItem<CountryItem>(
	      value: country,
	      child: Row(
		crossAxisAlignment: CrossAxisAlignment.center,
		children: <Widget>[
		  Image.asset(
		    "assets/images/flags/" +
		        country.code +
		        ".png",
		    height: 20,
		    width: 25,
		  ),
		  SizedBox(
		    width: 10,
		  ),
		  Text(country.name),
		],
	      ),
	    );
	  }).toList(),
	  onChanged: (CountryItem? country) {
	    setState(() {
	      selectedCountry = country;
	    });
	  },
	  onSaved: (value) {},
	),
),

flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel master, 3.1.0-0.0.pre.939, on Fedora Linux 36 (Workstation Edition) 5.17.8-300.fc36.x86_64, locale de_DE.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 32.1.0-rc1)
[✗] Chrome - develop for the web (Cannot find Chrome executable at google-chrome)
    ! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[✗] Linux toolchain - develop for Linux desktop
    ✗ clang++ is required for Linux development.
      It is likely available from your distribution (e.g.: apt install clang), or can be downloaded from https://releases.llvm.org/
    ✗ CMake is required for Linux development.
      It is likely available from your distribution (e.g.: apt install cmake), or can be downloaded from https://cmake.org/download/
    ✗ ninja is required for Linux development.
      It is likely available from your distribution (e.g.: apt install ninja-build), or can be downloaded from
      https://github.com/ninja-build/ninja/releases
    ✗ GTK 3.0 development libraries are required for Linux development.
      They are likely available from your distribution (e.g.: apt install libgtk-3-dev)
[✓] Android Studio (version 2021.1)
[✓] VS Code (version 1.67.2)
[✓] Connected device (2 available)
[✓] HTTP Host Availability

! Doctor found issues in 2 categories.

  String? selectedValue;
  List<String> items = [
    'Item1',
    'Item2',
    'Item3',
    'Item4',
  ];

  StickyPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    final size = MediaQuery.of(context).size;
    final width = size.width;

    return Scaffold(
      appBar: AppBar(title: Text("select demo")),
      body: Stack(
        children: [
          CustomScrollView(
            slivers: <Widget>[
              _selectMean(context, width),
            ],
          ),
        ],
      ),
    );
  }

  Widget _selectMean(context, width) {
    return SliverToBoxAdapter(
      child: DropdownButtonHideUnderline(
        child: DropdownButtonFormField2(
          onTap: () {},
          offset: const Offset(10, 50),
          alignment: AlignmentDirectional.centerStart,
          // selectedItemHighlightColor: Colors.blue,
          dropdownWidth: width - 20.w,
          decoration: InputDecoration(
            isDense: true,
            contentPadding: EdgeInsets.zero,
            border: OutlineInputBorder(
              borderRadius: BorderRadius.circular(15),
            ),
          ),
          hint: const Text(
            'Choose Text',
            style: TextStyle(fontSize: 14, color: Colors.blue),
          ),
          icon: const Icon(
            Icons.arrow_drop_down,
            color: Colors.black45,
          ),
          iconSize: 30,
          buttonHeight: 60,
          buttonPadding: const EdgeInsets.only(left: 20, right: 10),
          dropdownDecoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(15),
            boxShadow: const [],
          ),
          items: items
              .map((item) => DropdownMenuItem<String>(
                    value: item,
                    child: Text(
                      item,
                      style: const TextStyle(fontSize: 14, color: Colors.red),
                    ),
                  ))
              .toList(),
          validator: (value) {
            if (value == null) {
              return 'Please select gender.';
            }
          },
          dropdownFullScreen: true,
          onChanged: (value) {},
          onSaved: (value) {
            selectedValue = value.toString();
          },
        ),
      ),
    );
  }
}```

Center(
          child: FutureBuilder(
            future: employee,
            builder: ((context, AsyncSnapshot snapshot) {
              switch(snapshot.connectionState) {
                case ConnectionState.done:
                  return SingleChildScrollView(
                    child: Container(
                      width: 300,
                      height: 650,
                      decoration: BoxDecoration(
                          border: Border.all(color: Theme.of(context).primaryColor),
                          borderRadius: BorderRadius.circular(16)),
                      padding: const EdgeInsets.all(16),
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.start,
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          const Text(
                            'Редактирование данных сотрудника',
                            style: TextStyle(fontWeight: FontWeight.bold),
                          ),
                          const Divider(),
                          TextFormField(
                            controller: username,
                            decoration: const InputDecoration(
                              border: UnderlineInputBorder(),
                              labelText: 'Логин',
                            ),
                          ),
                          const SizedBox(
                            height: 30,
                          ),
                          TextFormField(
                            controller: password,
                            obscureText: true,
                            decoration: const InputDecoration(
                              border: UnderlineInputBorder(),
                              labelText: 'Пароль',
                            ),
                          ),
                          const SizedBox(
                            height: 30,
                          ),
                          TextFormField(
                            controller: confirmPassword,
                            obscureText: true,
                            decoration: const InputDecoration(
                              border: UnderlineInputBorder(),
                              labelText: 'Подтвердите пароль',
                            ),
                          ),
                          const SizedBox(
                            height: 30,
                          ),
                          TextFormField(
                            controller: firstname,
                            decoration: const InputDecoration(
                              border: UnderlineInputBorder(),
                              labelText: 'Имя сотрудника',
                            ),
                          ),
                          const SizedBox(
                            height: 30,
                          ),
                          TextFormField(
                            controller: lastname,
                            decoration: const InputDecoration(
                              border: UnderlineInputBorder(),
                              labelText: 'Фамилия сотрудника',
                            ),
                          ),
                          const SizedBox(
                            height: 30,
                          ),
                          const Text('Роль сотрудника'),
                          DropdownButton2(
                            isExpanded: true,
                            dropdownWidth: 300,
                            buttonPadding: const EdgeInsets.symmetric(horizontal: 16),
                            barrierColor: Colors.grey.withOpacity(0.2),
                            hint: Text(
                              'Выберите роль сотрудника',
                              style: TextStyle(
                                fontSize: 14,
                                color: Theme.of(context).hintColor,
                              ),
                            ),
                            items: userTypes
                                .map((item) => DropdownMenuItem<String>(
                                      value: item,
                                      child: Text(
                                        item,
                                        style: const TextStyle(
                                          fontSize: 14,
                                        ),
                                      ),
                                    ))
                                .toList(),
                            value: selectedType,
                            onChanged: (value) {
                              setState(() {
                                selectedType = value as String;
                              });
                            },
                            buttonHeight: 40,
                            buttonWidth: 300,
                            itemHeight: 40,
                          ),
                          const SizedBox(height: 30),
                          ElevatedButton(
                              onPressed: () {
                                updateEmployee(employeeId);
                              },
                              child: const Text('Редактировать'))
                        ],
                      ),
                    ),
                  );
                case ConnectionState.active:
                  return const CircularProgressIndicator();
                case ConnectionState.none:
                  return const CircularProgressIndicator();
                case ConnectionState.waiting: 
                  return const CircularProgressIndicator();
              }
            }),
          ),
    )

  final FormFieldValidator<T>? validator;
  final List<FastDropDownMenuItem<T>> items;
  final String? labelText;
  final String? helperText;
  final String? hintText;
  final T? initialValue;
  final ValueChanged<T?> onChanged;
  final Widget? suffixIcon;
  final double? itemHeight;
  final InputBorder border;
  final InputBorder focusedBorder;
  final String? previousInfo;
  final bool isNewAnimalForm;

  const FastDropdownButtonFormField({
    Key? key,
    required this.items,
    this.labelText,
    required this.onChanged,
    this.helperText,
    this.hintText,
    this.initialValue,
    this.itemHeight,
    this.suffixIcon,
    this.validator,
    this.focusedBorder =
        const OutlineInputBorder(borderSide: BorderSide(color: Colors.black54)),
    this.border =
        const OutlineInputBorder(borderSide: BorderSide(color: Colors.black12)),
    this.previousInfo,
    this.isNewAnimalForm = false,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Stack(
      clipBehavior: Clip.none,
      children: [
        Padding(
          padding: const EdgeInsets.only(bottom: 12.0, top: 7.0),
          child: DropdownButtonFormField2(
            autovalidateMode: AutovalidateMode.onUserInteraction,
            decoration: InputDecoration(
              filled: true,
              helperStyle: const TextStyle(fontSize: 14),
              helperText: helperText,
              suffixIcon: suffixIcon,
              contentPadding: const EdgeInsets.only(left: 8, bottom: 8),
              floatingLabelBehavior: FloatingLabelBehavior.always,
              hintStyle: const TextStyle(color: Colors.black54, fontSize: 16),
              fillColor: Colors.white,
              focusedBorder: focusedBorder,
              border: border,
            ),
            hint: hintText == null
                ? null
                : Text(hintText!, style: const TextStyle(color: Colors.black)),
            iconEnabledColor: fsGreen,
            isDense: false,
            isExpanded: true,
            items: items,
            itemHeight: itemHeight ?? kMinInteractiveDimension,
            onChanged: onChanged,
            openWithLongPress: true,
            validator: validator,
            value: initialValue,
            customItemsIndexes: [items.length],
          ),
        ),
      ],
    );
  }
}

static const Map<ShortcutActivator, Intent> _webShortcuts =
      <ShortcutActivator, Intent>{
    // On the web, up/down don't change focus, *except* in a <select>
    // element, which is what a dropdown emulates.
    SingleActivator(LogicalKeyboardKey.arrowDown):
        DirectionalFocusIntent(TraversalDirection.down),
    SingleActivator(LogicalKeyboardKey.arrowUp):
        DirectionalFocusIntent(TraversalDirection.up),
  };

          DropdownButton2(
                    onChanged: (text) {},
                    underline: const SizedBox.shrink(),
                    dropdownDecoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(14),
                    ),
                    value: state.dot.first.tenDot,
                    alignment: Alignment.center,
                    buttonDecoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(14),
                      border: Border.all(color: Colors.black26,),
                    ),
                    style: const TextStyle(
                      color: Colors.black,
                      fontSize: 10
                    ),
        )

Widget build(BuildContext context) {
    return ValueListenableBuilder(
      valueListenable: globals.app.homePageStateNotifier,
      builder: (context, HomePageData newState, _) {
        newState.saveData();
        loadState(newState);
        return Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              const Text(
                'You have pushed the button this many times:',
              ),
              Text(
                '$_counter',
                style: Theme.of(context).textTheme.headline4,
              ),
              DropdownButtonHideUnderline(
                child: DropdownButton2(
                  items: _themeDropdown,
                  value: _selectedItem,
                  onChanged: (MaterialColor? newval) {
                    _themeChanged(newval);
                  },
                  isExpanded: true,
                  buttonDecoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(15),
                    border: Border.all(
                      color: Colors.grey,
                    ),
                  ),
                  dropdownDecoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(15),
                    border: Border.all(
                      color: Colors.grey,
                    ),
                  ),
                  buttonWidth: 300,
                ),
              ),
            ],
          ),
        );
      },
    );
  }

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: 'package:flutter/src/widgets/scroll_controller.dart': Failed assertion: line 151 pos 12: '_positions.isNotEmpty': ScrollController not attached to any scroll views.
#0      _AssertionError._doThrowNew (dart:core-patch/errors_patch.dart:51:61)
#1      _AssertionError._throwNew (dart:core-patch/errors_patch.dart:40:5)
#2      ScrollController.animateTo (package:flutter/src/widgets/scroll_controller.dart:151:12)
#3      _DropdownMenuItemButtonState._handleFocusChange (package:dropdown_button2/dropdown_button2.dart:144:38)
#4      _InkResponseState.handleFocusUpdate (package:flutter/src/material/ink_well.dart:1028:27)
#5      _FocusState._handleFocusChanged (package:flutter/src/widgets/focus_scope.dart:632:27)
#6      ChangeNotifier.notifyListeners (package:flutter/src/foundation/change_notifier.dart:351:24)
#7      FocusNode._notify (package:flutter/src/widgets/focus_manager.dart:1038:5)
#8      FocusManager._applyFocusChange (package:flutter/src/widgets/focus_manager.dart:1804:12)
#9      _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
#10     _startMicrotaskLoop (dart:async/schedule_microtask.dart:49:5)

Error: Assertion failed: file:///D:/GitHub/flutter/packages/flutter/lib/src/widgets/scroll_controller.dart:151:12
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart
266:49  throw_
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart
29:3    assertFailed
packages/flutter/src/widgets/scroll_controller.dart 151:23
animateTo
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54
runBody
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 123:5
_async
packages/flutter/src/widgets/scroll_controller.dart 146:25
animateTo
packages/dropdown_button2/dropdown_button2.dart 144:20
[_handleFocusChange]
packages/flutter/src/material/ink_well.dart 1028:27
handleFocusUpdate
packages/flutter/src/widgets/focus_scope.dart 632:27
[_handleFocusChanged]
packages/flutter/src/foundation/change_notifier.dart 351:24
notifyListeners
packages/flutter/src/widgets/focus_manager.dart 1038:5
[_notify]
packages/flutter/src/widgets/focus_manager.dart 1804:11
[_applyFocusChange]
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/schedule_microtask.dart 40:11
_microtaskLoop
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/async/schedule_microtask.dart 49:5
_startMicrotaskLoop
C:/b/s/w/ir/cache/builder/src/out/host_debug/dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 166:15
<fn>

MyDropdown extends from stateful ....
isOpen = false;

`DropdownButtonFormField2(

isOpen: (value){
  setState((){
    isOpen = value;
  });
},
)

DropdownButton2<T>(
      isExpanded: true,
      customButton: Row(mainAxisSize: MainAxisSize.max, children: <Widget>[hint, SvgPicture.asset(getPic('icon_menu_down.svg'), width: 7, height: 7)]),
      items: items,
      value: selectValue,
      onChanged: onChanged,
      icon: SvgPicture.asset(
        getPic('icon_menu_down.svg'),
        width: 7,
        height: 7,
      ),
      buttonHeight: 20,
      buttonWidth: 140,
      itemHeight: 40,
      itemPadding: const EdgeInsets.symmetric(horizontal: 12),
      dropdownMaxHeight: 200,
      dropdownWidth: 200,
      dropdownDecoration: ViewDecoration.decoration(),
      // dropdownElevation: 4,
      scrollbarRadius: const Radius.circular(40),
      scrollbarThickness: 4,
      scrollbarAlwaysShow: true,
      offset: const Offset(-20, -10),
    )