how to delete item list using pop up menu - flutter

Question

How do i delete an item list when i clicked on a pop up menu button? however, my list and pop up menu is in two separate files. i need to know which one im deleting according to which list item is pressed on.

pop_up_menu.dart:

import 'package:flutter/material.dart';

class PopUpMenu extends StatelessWidget {
  void showMenuSelection(String value) {
    print("pressed");
  }

  @override
  Widget build(BuildContext context) {
    return PopupMenuButton<String>(
      padding: EdgeInsets.zero,
      icon: Icon(Icons.more_vert),
      onSelected: showMenuSelection,
      itemBuilder: (BuildContext context) => <PopupMenuEntry<String>>[
            const PopupMenuItem<String>(
                value: 'Create another',
                child: ListTile(
                    leading: Icon(Icons.add), title: Text('Create another'))),
            const PopupMenuItem<String>(
                value: 'Delete',
                child: ListTile(
                    leading: Icon(Icons.delete), title: Text('Delete')))
          ],
    );
  }
}

So imported this pop up menu in list_tile.dart, whenever i clicked on the pop up menu button, 'Delete', i need to remove the selected list item that has pressed the pop up menu

List_tile.dart:

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

var levelsData = [];

class ListTile extends StatefulWidget {
  @override
  ListTileState createState() => new ListTileState();
}

class ListTileState extends State<ListTile> {
  @override
  Widget build(BuildContext context) {
    return ListView.builder(
      itemBuilder: (BuildContext context, int index) => Card(
            child: SingleChildScrollView(
              child: StuffInTiles(
                levelsData[index]['user_id'],
                levelsData[index]['price'],
              ),
            ),
          ),
      itemCount: levelsData.length,
    );
  }
}

class StuffInTiles extends StatelessWidget {
  final String userId;
  final double price;

  StuffInTiles(this.userId, this.price);

  @override
  Widget build(BuildContext context) {
    List<dynamic> _getChildren() {
      List<Widget> children = [];
      levelsData.forEach(
        (element) {
          if (price.toString() == element['price'].toString()) {
            children.add(ListTile(
                title: Text("@" + element['price'].toString(),
                    style: TextStyle(color: Colors.lightGreen)),
                subtitle: Text(
                    "Created on 01 Jun 2018 at 06:24AM \n when price was " +
                        element['price'].toString()),
                trailing: PopUpMenu()));
          }
        },
      );
      return children;
    }
  }
}

So each item in this list has a pop up menu with delete option in that menu. When the delete option is pressed, it has to delete the item that triggered it.

Example: when the pop up menu button delete for user2 is pressed, it should delete user2.

Answer 1

Add a callback function to your PopUpMenu class:

class PopUpMenu extends StatelessWidget {
  VoidCallback onDelete;

  PopUpMenu({this.onDelete});

  void showMenuSelection(String value) {
    switch (value) {
      case 'Delete':
        onDelete();
        break;
      // Other cases for other menu options
    }
  }

Then when creating it in your original class:

         ...
                trailing: PopUpMenu(
                  onDelete: () {
                    levelsData.removeWhere((element) => element == element);
                  }
                )));
          }

General rule of thumb in Flutter is to pass a callback down to children rather than try to access data in a parent.

You may also need to make your StuffInTiles Widget Stateful and add setState(() {}); to your onDelete, as simply removing the value won't actually update your view with the new list.