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


Reducing is the act of taking a collection and simplifying it down to a single value. For a list of numbers, you might want to use the reduce function to quickly calculate the sum of those numbers. For a list of strings, you can use reduce to concatenate all the values.

A reduce function will provide two parameters, the previous result, and the current elements: 

final total = allAges.reduce((total, age) => total + age);

The first time this function runs, the total value will be 0. The function will return 0 plus the first age value, 10. In the second iteration, the total value will 10. That function will then return 10 + 9. This process will continue until all the elements have been added to the total value.

Since higher-order functions are mostly abstractions on top of loops, we could write this code without the reduce function, like so:

int sum = 0;
for (int age in allAges) {
sum += age;

Just like with where(), Dart also provides alternative implementations of reduce that you may want to use. The fold() function allows you to provide an initial value for the reducer. This is helpful for non-numeric types such as strings or if you do not want your code to start reducing from 0:

final oddTotal = allAges.fold<int>(-1000, (total, age) => total + age);