Preface

Welcome to Android Design Patterns and Best Practice, a comprehensive guide to how to get the most out of your apps with the tried and tested programming philosophy, design patterns. These patterns provide a logical and elegant approach to solving many of the development problems that coders face. These patterns act as a guide creating a clear path from problem to solution, and although applying a design pattern does not guarantee best practice in itself, it will hugely assist the process and make the discovery of design flaws far easier. Design patterns can be implemented on very many platforms and written in as many programming languages. Some code libraries even apply patterns as part of their internal mechanics, and many readers will already be familiar with the Java Observer and Observable classes. The Android SDK we will be exploring makes great use of many patterns, such as factories, builders and listeners (which are really just observer patterns). Although we will cover these built-in design patterns, the book will mostly explore how we can build our own, custom made, patterns and apply them to Android development. Rather than approach each design pattern in turn, this book approaches the subject from the perspective of a developer, moving through each aspect of app development exploring individual design patterns as they would arise in the course of building an Android app. To clarify this journey, we will be focusing on a single imaginary app, designed to support a small business. This will take us from application conception through to publication, covering such topics as UI design, internal logic and user interaction along the way. During each of these steps we will explore those design patterns that are relevant to that process, by first exploring the pattern in its abstract form and then applying it to that particular situation. By the end of the book you will have learned how design patterns can be applied to all aspects of Android development and how using them assists best practice. It is the concept of design patterns that is more important than any specific pattern itself. Patterns can, and should, be adapted to suit our specific purposes, and by learning this way of approaching app development, we can even go on to create entirely original patterns of our own.