Book Image

Flutter Cookbook

By : Simone Alessandria, Brian Kayfitz
4 (1)
Book Image

Flutter Cookbook

4 (1)
By: Simone Alessandria, Brian Kayfitz

Overview of this book

“Anyone interested in developing Flutter applications for Android or iOS should have a copy of this book on their desk.” – Amazon 5* Review Lauded as the ‘Flutter bible’ for new and experienced mobile app developers, this recipe-based guide will teach you the best practices for robust app development, as well as how to solve cross-platform development issues. From setting up and customizing your development environment to error handling and debugging, The Flutter Cookbook covers the how-tos as well as the principles behind them. As you progress, the recipes in this book will get you up to speed with the main tasks involved in app development, such as user interface and user experience (UI/UX) design, API design, and creating animations. Later chapters will focus on routing, retrieving data from web services, and persisting data locally. A dedicated section also covers Firebase and its machine learning capabilities. The last chapter is specifically designed to help you create apps for the web and desktop (Windows, Mac, and Linux). Throughout the book, you’ll also find recipes that cover the most important features needed to build a cross-platform application, along with insights into running a single codebase on different platforms. By the end of this Flutter book, you’ll be writing and delivering fully functional apps with confidence.
Table of Contents (17 chapters)
About Packt

How to do it...

Let's continue with the aforementioned, less than optimal code and reimplement it with cascades:

  1. Recreate the UrlBuilder class, but without any of the extra methods that are usually required to implement this pattern. This new class will not look that different from a mutable Dart object:
class UrlBuilder {
String scheme;
String host;
List<String> routes;

String toString() {
assert(scheme != null);
assert(host != null);
final paths = [host, if (routes != null) ...routes];
final path = paths.join('/');

return '$scheme://$path';

  1. Next, you are going to use the cascade operator to get the builder pattern for free. Write this function just after the declaration of the UrlBuilder class:
void cascadePlayground() {
final url = UrlBuilder()
..scheme = 'https' = ''
..routes = [

  1. The cascade operator is not exclusively used for the builder pattern. It can also be used to, well, cascade similar operations on the same object. Add the following code inside the cascadePlayground function:
final numbers = [342, 23423, 53, 232, 534]
..insert(0, 10)
..sort((a, b) => a.compareTo(b));

print('The largest number in the list is ${numbers.last}');