PopupMenuItem vs ListView, ReorderableListView and ReorderableList (problem in PopupMenuItem vs ReorderableListView) (flutter 1.0.0, flutter_reorderable_list 0.1.1)

main.dart

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

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<MyItem> _sampleItems;
  int _selectedView;

  @override
  void initState() {
    super.initState();
    _selectedView = 0;

    _sampleItems = [];
    for(int i = 1; i < 100; i++) {
      _sampleItems.add(MyItem(i.toString(), randomIcons[i], "Item $i"));
    }
  }

  Widget _buildOptions(MyItem item) {
    return PopupMenuButton(
      itemBuilder: (BuildContext context) {
        return [
          new PopupMenuItem(child: new Text("edit"), value: "edit"),
          new PopupMenuItem(child: new Text("delete"), value: "delete"),
        ];
      },
      onSelected: (selected) async {
        await showDialog(context: context,
          builder: (BuildContext context) {
            return SimpleDialog(
              title: Text(selected),
              contentPadding: EdgeInsets.all(25.0),
              children: <Widget>[Text("Item [${item.title}], Operation [$selected].")],
            );
          }
        );
      },
    );
  }

  Widget _buildListTile(BuildContext context, MyItem item, {ReorderableListener listener}) {
    Widget options = _buildOptions(item);

    if (listener != null)
      options = Row(
        mainAxisAlignment: MainAxisAlignment.end,
        mainAxisSize: MainAxisSize.min,
        children: <Widget>[
          options,
          listener,
        ],
      );

    return ListTile(key: Key(item.key),
      leading: Icon(item.icon),
      title: Text(item.title),
      trailing: options,
    );
  }

  BoxDecoration _decoration(ReorderableItemState state) {
    if (state == ReorderableItemState.dragProxy ||
        state == ReorderableItemState.dragProxyFinished) {
      return BoxDecoration(color: Color(0xD0FFFFFF));
    } else {
      bool placeholder = state == ReorderableItemState.placeholder;
      return BoxDecoration(
          border: Border(
              top: !placeholder
                  ? Divider.createBorderSide(context)
                  : BorderSide.none,
              bottom: placeholder
                  ? BorderSide.none
                  : Divider.createBorderSide(context)),
          color: placeholder ? null : Colors.white);
    }
  }

  Widget _buildReorderableItem(BuildContext context, int index) {
    var item = _sampleItems[index]; 
    return ReorderableItem(
      key: Key(item.key),
      childBuilder: (BuildContext context, ReorderableItemState state) {
        BoxDecoration decoration = _decoration(state);
        return Container(
          decoration: decoration,
          child: Opacity(
            opacity: state == ReorderableItemState.placeholder ? 0.0 : 1.0,
            child: _buildListTile(context, item,
                    listener: ReorderableListener(
                                child: Center(child: Icon(Icons.reorder)))),
          ),
        );
      },
    );
  }

  int _indexOfKey(Key key) {
    return _sampleItems.indexWhere((MyItem i) => Key(i.key) == key);
  }

  Widget _buildReorderableList(BuildContext context) {
    return ReorderableList(
      child: CustomScrollView(
        slivers: <Widget>[
          SliverList(
            delegate: SliverChildBuilderDelegate(
              (BuildContext context, int index) {
                return _buildReorderableItem(context, index);
              },
              childCount: _sampleItems.length,
            ),
          )          
        ],
      ),
      onReorder: (Key draggedItem, Key newPosition) {
        int draggingIndex = _indexOfKey(draggedItem);
        int newPositionIndex = _indexOfKey(newPosition);

        final item = _sampleItems[draggingIndex];
        setState(() {
          _sampleItems.removeAt(draggingIndex);
          _sampleItems.insert(newPositionIndex, item);
        });
        return true;
      },
    );
  }

  Widget _buildReorderableListView(BuildContext context) {
    return ReorderableListView(
      children: _sampleItems
                  .map((MyItem item) => _buildListTile(context, item)).toList(),
      onReorder: (oldIndex, newIndex) {
        setState(() {
          if (newIndex > _sampleItems.length) newIndex = _sampleItems.length;
          if (oldIndex < newIndex) newIndex--;

          MyItem item = _sampleItems[oldIndex];
          _sampleItems.remove(item);
          _sampleItems.insert(newIndex, item);
        });
      },
    );
  }

  Widget _buildListView(BuildContext context) {
    return ListView(
      children: _sampleItems
                  .map((MyItem item) => _buildListTile(context, item)).toList(),
    );
  }

  void _radioChanged(int value) {
    setState(() => _selectedView = value);
  }

  Widget _buildRadio(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.spaceBetween,
      children: <Widget>[
        RadioListTile<int>(
          value: 0,
          groupValue: _selectedView,
          onChanged: _radioChanged,
          title: Text("ListView"),
        ),
        RadioListTile<int>(
          value: 1,
          groupValue: _selectedView,
          onChanged: _radioChanged,
          title: Text("ReorderableListView"),
        ),
        RadioListTile<int>(
          value: 2,
          groupValue: _selectedView,
          onChanged: _radioChanged,
          title: Text("ReorderableList"),
        ),
      ],
    );
  }

  Widget _view(BuildContext context) {
    if (_selectedView == 1)
      return _buildReorderableListView(context);

    if (_selectedView == 2)
      return _buildReorderableList(context);

    return _buildListView(context);
  }

  Widget _buildBody(BuildContext context) {
    return Container(
      padding: EdgeInsets.all(10.0),
      child: Column(
        children: <Widget>[
          _buildRadio(context),
          Expanded(child: _view(context)),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(title)),
      body: _buildBody(context),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: title,
      theme: ThemeData(
        primarySwatch: Colors.pink,
      ),
      home: MyHomePage(),
    );
  }
}

void main() => runApp(MyApp());

class MyItem {
  MyItem(this.key, this.icon, this.title);

  final String key;
  final IconData icon;
  final String title;

  bool operator ==(o) => o is MyItem && o.key == key;
  int get hashCode => key.hashCode;
}

const title = "PopupMenuItem test";

List<IconData> randomIcons = [
  Icons.g_translate, Icons.backspace, Icons.backup, Icons.battery_alert, Icons.cached, Icons.cake, Icons.calendar_today, 
  Icons.camera_enhance, Icons.camera_front, Icons.camera_rear, Icons.camera_roll, Icons.camera, Icons.cancel, Icons.card_giftcard, Icons.card_membership, Icons.card_travel, Icons.casino, Icons.cast_connected, 
  Icons.calendar_view_day, Icons.call_end, Icons.call_made, Icons.call_merge, Icons.call_missed_outgoing, Icons.call_missed, Icons.call_received, Icons.call_split, Icons.call_to_action, Icons.call, Icons.camera_alt, 
  Icons.laptop, Icons.last_page, Icons.launch, Icons.layers_clear, Icons.layers, Icons.mail_outline, Icons.mail, Icons.map, Icons.markunread_mailbox, Icons.markunread, Icons.maximize, 
  Icons.cast, Icons.category, Icons.dashboard, Icons.data_usage, Icons.date_range, Icons.face, Icons.fast_forward, Icons.fast_rewind, Icons.fastfood, Icons.favorite_border, Icons.favorite, 
  Icons.gamepad, Icons.games, Icons.gavel, Icons.label_important, Icons.label_outline, Icons.label, Icons.landscape, Icons.language, Icons.laptop_chromebook, Icons.laptop_mac, Icons.laptop_windows, 
  Icons.wc, Icons.adb, Icons.add_a_photo, Icons.add_alarm, Icons.add_alert, Icons.add_box, Icons.add_call, Icons.add_circle_outline, Icons.add_circle, Icons.add_comment, Icons.add_location, 
  Icons.panorama_vertical, Icons.panorama_wide_angle, Icons.panorama, Icons.party_mode, Icons.pause_circle_filled, Icons.pause_circle_outline, Icons.pause, Icons.payment, Icons.radio_button_checked, Icons.radio_button_unchecked, Icons.radio,
  Icons.nature_people, Icons.nature, Icons.navigate_before, Icons.navigate_next, Icons.navigation, Icons.pages, Icons.pageview, Icons.palette, Icons.pan_tool, Icons.panorama_fish_eye, Icons.panorama_horizontal, 
  Icons.ac_unit, Icons.access_alarm, Icons.access_alarms, Icons.access_time, Icons.accessibility_new, Icons.accessibility, Icons.accessible_forward, Icons.accessible, Icons.account_balance_wallet, Icons.account_balance, Icons.account_box, 
  Icons.delete_forever, Icons.delete_outline, Icons.delete_sweep, Icons.delete, Icons.departure_board, Icons.description, Icons.desktop_mac, Icons.desktop_windows, Icons.details, Icons.developer_board, Icons.developer_mode, 
  Icons.rate_review, Icons.satellite, Icons.save_alt, Icons.save, Icons.tab_unselected, Icons.tab, Icons.table_chart, Icons.tablet_android, Icons.tablet_mac, Icons.tablet, 
  Icons.tag_faces, Icons.tap_and_play, Icons.wallpaper, Icons.warning, Icons.watch_later, Icons.watch, Icons.wb_auto, Icons.wb_cloudy, Icons.wb_incandescent, Icons.wb_iridescent, Icons.wb_sunny, 
  Icons.account_circle, Icons.scanner, Icons.scatter_plot, Icons.schedule, Icons.school, Icons.score, Icons.screen_lock_landscape, Icons.screen_lock_portrait, Icons.screen_lock_rotation, Icons.screen_rotation, Icons.screen_share, 
  Icons.add_photo_alternate, Icons.add_shopping_cart, Icons.add_to_home_screen, Icons.add_to_photos, Icons.add_to_queue, Icons.add, Icons.adjust, Icons.edit_attributes, Icons.edit_location, Icons.edit, Icons.hd, 
  Icons.hdr_off, Icons.hdr_on, Icons.hdr_strong, Icons.hdr_weak, Icons.sd_card, Icons.sd_storage, Icons.beach_access, Icons.beenhere, Icons.center_focus_strong, Icons.center_focus_weak, Icons.dehaze, 
  Icons.device_hub, Icons.device_unknown, Icons.devices_other, Icons.devices, Icons.featured_play_list, Icons.featured_video, Icons.feedback, Icons.gesture, Icons.get_app, Icons.headset_mic, Icons.headset_off, 
  Icons.headset, Icons.healing, Icons.hearing, Icons.help_outline, Icons.help, Icons.keyboard_arrow_down, Icons.keyboard_arrow_left, Icons.keyboard_arrow_right, Icons.keyboard_arrow_up, Icons.keyboard_backspace, Icons.keyboard_capslock, 
  Icons.keyboard_hide, Icons.keyboard_return, Icons.keyboard_tab, Icons.keyboard_voice, Icons.keyboard, Icons.leak_add, Icons.leak_remove, Icons.lens, Icons.memory, Icons.menu, Icons.merge_type, 
  Icons.message, Icons.near_me, Icons.network_cell, Icons.network_check, Icons.network_locked, Icons.network_wifi, Icons.new_releases, Icons.next_week, Icons.people_outline, Icons.people, Icons.perm_camera_mic, 
  Icons.perm_contact_calendar, Icons.perm_data_setting, Icons.perm_device_information, Icons.perm_identity, Icons.perm_media, Icons.perm_phone_msg, Icons.perm_scan_wifi, Icons.person_add, Icons.person_outline, Icons.person_pin_circle, Icons.person_pin, 
  Icons.person, Icons.personal_video, Icons.pets, Icons.receipt, Icons.recent_actors, Icons.record_voice_over, Icons.redeem, Icons.redo, Icons.refresh, Icons.remove_circle_outline, Icons.remove_circle, 
  Icons.remove_from_queue, Icons.remove_red_eye, Icons.remove_shopping_cart, Icons.remove, Icons.reorder, Icons.repeat_one, Icons.repeat, Icons.replay_10, Icons.replay_30, Icons.replay_5, Icons.replay, 
  Icons.reply_all, Icons.reply, Icons.report_off, Icons.report_problem, Icons.report, Icons.restaurant_menu, Icons.restaurant, Icons.restore_from_trash, Icons.restore_page, Icons.restore, Icons.search, 
  Icons.security, Icons.select_all, Icons.send, Icons.sentiment_dissatisfied, Icons.sentiment_neutral, Icons.sentiment_satisfied, Icons.sentiment_very_dissatisfied, Icons.sentiment_very_satisfied, Icons.settings_applications, Icons.settings_backup_restore, Icons.settings_bluetooth, 
  Icons.settings_brightness, Icons.settings_cell, Icons.settings_ethernet, Icons.settings_input_antenna, Icons.settings_input_component, Icons.settings_input_composite, Icons.settings_input_hdmi, Icons.settings_input_svideo, Icons.settings_overscan, Icons.settings_phone, Icons.settings_power, 
  Icons.settings_remote, Icons.settings_system_daydream, Icons.settings_voice, Icons.settings, Icons.terrain, Icons.text_fields, Icons.text_format, Icons.text_rotate_up, Icons.text_rotate_vertical, Icons.text_rotation_angledown, Icons.text_rotation_angleup, Icons.battery_charging_full, 
  Icons.text_rotation_down, Icons.text_rotation_none, Icons.textsms, Icons.texture, Icons.verified_user, Icons.vertical_align_bottom, Icons.vertical_align_center, Icons.vertical_align_top, Icons.web_asset, Icons.web, Icons.weekend, 
  Icons.nfc, Icons.offline_bolt, Icons.offline_pin, Icons.change_history, Icons.chat_bubble_outline, Icons.chat_bubble, Icons.chat, Icons.check_box_outline_blank, Icons.check_box, Icons.check_circle_outline, Icons.check_circle, 
];

Note as PopupMenuItem gets misplaced in ReorderableListView.