Flutter PopupMenuButton

In Flutter, PopupMenuButton is a widget that provides a menu for selecting among a set of options. When tapped, it displays a list of items in a pop-up that the user can choose from.

Here’s a basic example of how to use PopupMenuButton:

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: PopupMenuExample(),
    );
  }
}

class PopupMenuExample extends StatefulWidget {
  @override
  _PopupMenuExampleState createState() => _PopupMenuExampleState();
}

class _PopupMenuExampleState extends State<PopupMenuExample> {
  String _selectedOption = 'None';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Popup Menu Button Example'),
        actions: [
          PopupMenuButton<String>(
            onSelected: (String result) {
              setState(() {
                _selectedOption = result;
              });
            },
            itemBuilder: (BuildContext context) => <PopupMenuEntry<String>>[
              const PopupMenuItem<String>(
                value: 'Option 1',
                child: Text('Option 1'),
              ),
              const PopupMenuItem<String>(
                value: 'Option 2',
                child: Text('Option 2'),
              ),
              const PopupMenuItem<String>(
                value: 'Option 3',
                child: Text('Option 3'),
              ),
            ],
          ),
        ],
      ),
      body: Center(
        child: Text('Selected option: $_selectedOption'),
      ),
    );
  }
}

Explanation:

• PopupMenuButton: Creates a button that shows a pop-up menu.
• onSelected: Callback that is invoked when an item from the menu is selected.
• PopupMenuItem: Each item in the pop-up menu with a value and child (usually a Text widget).