BackButton in Flutter

In Flutter, a BackButton is a widget that provides a button to navigate back to the previous screen or route. It is typically used in the AppBar to allow users to navigate back.

Properties:

• onPressed: The callback function to handle the back button press.
• color: The color of the back button icon.
• tooltip: The tooltip to display when the back button is long-pressed.

AppBar(
  leading: BackButton(
    onPressed: () {
      Navigator.pop(context);
    },
    color: Colors.white,
  ),
  title: Text("Screen Title"),
)

Where to use BackButton in Flutter

The BackButton widget in Flutter is typically used in the following scenarios:

1. AppBar: As the leading widget, users can navigate back to the previous screen.
2. Dialogs: Dialogs provide a way to dismiss the dialog and return to the previous screen.
3. Nested Navigation: In nested navigation scenarios, such as when using Navigator multiple routes, users can navigate back to the previous route.
4. Custom Navigation: In custom navigation scenarios, such as when using a custom navigation bar or footer, it provides a way to navigate back to the previous screen.

import 'package:flutter/material.dart';

// Define the BackButtonDemo widget, which is a StatefulWidget
class BackButtonDemo extends StatefulWidget {
  // Constructor for the BackButtonDemo widget
  const BackButtonDemo({Key? key}) : super(key: key);

  @override
  State<BackButtonDemo> createState() => _BackButtonDemoState();
}

// State class for BackButtonDemo
class _BackButtonDemoState extends State<BackButtonDemo> {
  @override
  Widget build(BuildContext context) {
    return SafeArea(
      // Ensures that the widget is positioned within the safe area of the screen (avoiding notches, status bar, etc.)
      child: Scaffold(
        // Provides basic material design visual layout structure
        appBar: AppBar(
          // Title of the AppBar
          title: Text(
            "Back Button",
            style: TextStyle(
              color: Colors.white, // Title text color
              fontWeight: FontWeight.bold, // Title text weight
            ),
          ),
          flexibleSpace: Container(
            // Custom decoration for the AppBar
            decoration: BoxDecoration(
              gradient: LinearGradient(
                colors: [Colors.deepPurple, Colors.orangeAccent], // Gradient colors
                begin: Alignment.topLeft, // Gradient start alignment
                end: Alignment.topRight, // Gradient end alignment
              ),
            ),
          ),
          leading: BackButton(
            // BackButton widget to provide a back navigation functionality
            color: Colors.white, // Icon color
            onPressed: () {
              // When the BackButton is pressed, navigate back to the previous screen
              Navigator.pop(context);
            },
          ),
        ),
        body: Column(
          children: [
            // This is where you can add other widgets for the body of the Scaffold
          ],
        ),
      ),
    );
  }
}