PopupMenu

CustomPopupMenu.dart

import 'package:flutter/material.dart' hide showMenu;
import 'package:flutter/material.dart' as material show showMenu;

/// A mixin to provide convenience methods to record a tap position and show a popup menu.
mixin CustomPopupMenu<T extends StatefulWidget> on State<T> {
  Offset _tapPosition;

  /// Pass this method to an onTapDown parameter to record the tap position.
  void storePosition(TapDownDetails details) =>
      _tapPosition = details.globalPosition;

  /// Use this method to show the menu.
  Future<T> showMenu<T>({
    @required BuildContext context,
    @required List<PopupMenuEntry<T>> items,
    T initialValue,
    double elevation,
    String semanticLabel,
    ShapeBorder shape,
    Color color,
    bool captureInheritedThemes = true,
    bool useRootNavigator = false,
  }) {
    final RenderBox overlay = Overlay.of(context).context.findRenderObject();

    return material.showMenu<T>(
      context: context,
      position: RelativeRect.fromLTRB(
        _tapPosition.dx,
        _tapPosition.dy,
        overlay.size.width - _tapPosition.dx,
        overlay.size.height - _tapPosition.dy,
      ),
      items: items,
      initialValue: initialValue,
      elevation: elevation,
      semanticLabel: semanticLabel,
      shape: shape,
      color: color,
      captureInheritedThemes: captureInheritedThemes,
      useRootNavigator: useRootNavigator,
    );
  }
}

sTwo.dart

import 'package:flutter/material.dart';
import 'package:flutter_arch_training/CustomPopupMenu.dart';

class TwoScreen extends StatefulWidget {
  static const routeName = "/OneScreen";

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

class _TwoScreenState extends State<TwoScreen>
    with AutomaticKeepAliveClientMixin<TwoScreen> {
  @override
  bool get wantKeepAlive => true;

  @override
  Widget build(BuildContext context) {
    print("Two build");
    return Scaffold(
      appBar: AppBar(
        title: Text("TwoScreen"),
      ),
      body: Container(
        child: Column(
          children: [
            DvegasaCard(),
            DvegasaCard(),
            DvegasaCard(),
            DvegasaCard(),
            DvegasaCard(),
          ],
        ),
      ),
    );
  }
}

class DvegasaCard extends StatefulWidget {
  @override
  _DvegasaCardState createState() => _DvegasaCardState();
}

class _DvegasaCardState extends State<DvegasaCard> with CustomPopupMenu {
  bool isHighlighted = false;

  void _showPopup() {
    setState(() => isHighlighted = true);
    this.showMenu(
      color: Colors.transparent,
      elevation: 0,
      context: context,
      items: [MyMenu()],
    ).then((value) {
      print("showMenu clicked $value");
      setState(() => isHighlighted = false);
    });
  }

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onLongPress: _showPopup,
      onTapDown: storePosition,
      child: Container(
        color: Colors.transparent,
        width: double.infinity,
        child: Card(
          elevation: isHighlighted ? 4 : 0,
          color:
              isHighlighted ? Color.fromRGBO(240, 240, 240, 1) : Colors.white,
          child: Padding(
            padding: const EdgeInsets.symmetric(vertical: 20),
            child: Text(
              "veh",
              textAlign: TextAlign.center,
            ),
          ),
        ),
      ),
    );
  }
}

class MyMenu extends PopupMenuEntry<int> {
  @override
  _MyMenuState createState() => _MyMenuState();

  @override
  double get height => 100;
  // height doesn't matter, as long as we are not giving
  // initialValue to showMenu().

  @override
  bool represents(int value) => false;
}

class _MyMenuState extends State<MyMenu> {
  Widget _buildItem({
    @required IconData icon,
    @required String label,
    @required int value,
    Color color = Colors.black87,
  }) {
    return InkWell(
      onTap: () => Navigator.of(context).pop(value),
      highlightColor: Colors.black.withOpacity(0.05),
      splashColor: Colors.black.withOpacity(0.05),
      child: Container(
        padding: EdgeInsets.symmetric(horizontal: 10, vertical: 12),
        child: Row(
          children: [
            Icon(
              icon,
              color: color,
            ),
            SizedBox(width: 10),
            Flexible(
              child: Text(
                label,
                style: TextStyle(
                  color: color,
                  fontSize: 15,
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Card(
      elevation: 4,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(6),
      ),
      child: Padding(
        padding: const EdgeInsets.symmetric(vertical: 6),
        child: Column(
          children: [
            _buildItem(
              icon: Icons.alarm,
              label: "Уведомить за...",
              value: 1,
            ),
            _buildItem(
              icon: Icons.map_outlined,
              label: "Где аудитория?",
              value: 2,
            ),
            Divider(),
            _buildItem(
              icon: Icons.share_outlined,
              label: "Поделиться",
              value: 3,
            ),
          ],
        ),
      ),
    );
  }
}