Flutter - ListTile Widget

// ignore_for_file: deprecated_member_use
// This comment tells the Dart analyzer to ignore warnings about deprecated members being used.
// Importing Flutter's Material package which contains UI components.
import 'package:flutter/material.dart';

// The main function is the entry point of the Flutter application.
void main() {
  runApp(const MyApp()); // Running the root widget of the app.
}

// Defining a stateless widget named MyApp.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key); // Constructor with optional key.

  // The build method describes the part of the UI represented by this widget.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'ListTile', // Title of the app.
      theme: ThemeData(primarySwatch: Colors.blue), // Setting the app theme with a blue color.
      home: const MyHomePage(), // Setting MyHomePage as the home screen.
      debugShowCheckedModeBanner: false, // Hides the debug banner.
    );
  }
}

// Defining a stateful widget named MyHomePage.
class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key); // Constructor with optional key.

  @override
  // Creates the mutable state for this widget.
  _MyHomePageState createState() => _MyHomePageState();
}

// The state class associated with MyHomePage.
class _MyHomePageState extends State<MyHomePage> {
  String txt = ''; // Variable to hold the text shown after tapping ListTile.

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // AppBar displays a toolbar at the top of the screen.
      appBar: AppBar(
        title: const Text('GeeksforGeeks'), // AppBar title.
        backgroundColor: Colors.green, // Background color of AppBar.
        foregroundColor: Colors.white, // Text/icon color on AppBar.
      ),
      backgroundColor: Colors.grey[100], // Background color of the page body.

      // The main content of the page, organized in a column.
      body: Column(
        children: <Widget>[
          // Adds padding around the ListTile container.
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: Container(
              color: Colors.blue[50], // Background color of the container.
              child: ListTile(
                leading: const Icon(Icons.add), // Icon displayed at the start.
                title: const Text('GFG title', textScaleFactor: 1.5), // Main title with increased text size.
                trailing: const Icon(Icons.done), // Icon displayed at the end.
                subtitle: const Text('This is subtitle'), // Secondary text below the title.
                selected: true, // Visually marks the ListTile as selected.
                // Function executed when the ListTile is tapped.
                onTap: () {
                  setState(() {
                    txt = 'List Tile pressed'; // Updates the text when tapped.
                  });
                },
              ),
            ),
          ),
          // Displays the updated text when ListTile is pressed.
          Text(txt, textScaleFactor: 2), // Doubles the size of the text.
        ],
      ),
    );
  }
}