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 it works...

With Dart, you can write functions with unnamed (the old way)named, and unnamed optional parameters. In Flutter, unnamed optional parameters are the most common style you will be using, especially with widgets (more on this in the following chapters).

Named parameters can also remove ambiguity from what each parameter is supposed to do. Take a look at the following line from the preceding code example:

unnamed('Huxley', 3);

Now, compare it with this line:

duplicate('Mikey', times: 3);

In the first example, it isn't immediately clear what the purpose of each parameter is. In the second example, the times parameter immediately tells you that the text Mikey will be duplicated three times. This can go a long way with functions that have rather long parameter lists, where it can be difficult to remember the expected order of the parameters. Take a look at how this syntax is put to work in the Flutter framework:

const EdgeInsets.all(10.0),
height: 48.0,
child: Text('Named parameters are great!'),

This isn't even all the properties that are available for containers – it can get much longer. Without named parameters, this sort of syntax could be almost impossible to read.

Type annotation for Dart functions is optional.


You can completely omit it if you are so inclined. However, for any parameter or even function name that does not have type annotation, Dart will assume that it is of the dynamic type. Since we would like to exploit Dart's type system for all it's worth, dynamic types should be avoided. That is why we always strive to add the void keyword in front of any function that doesn't return a value.