Xamarin with Visual Studio. Launch your mobile development career by creating Android and iOS applications using .NET and C (Alessandro Del Sole)（Z-Library）

Xamarin with Visual Studio Launch Your Mobile Development Career by Creating Android and iOS Applications Using.NET and C# Alessandro Del Sole www.bpbonline.com

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Dedicated to My wonderful wife Angelica, I’ll love you until the end

About the Author Alessandro Del Sole is a senior software engineer working on building mobile apps with Xamarin in the healthcare industry. He has been using Xamarin since 2015 and is a Xamarin Certified Mobile Developer. Alessandro has also been Microsoft Most Valuable Professional since 2008, and has authored many technical books, eBooks, articles, instructional videos and has been speaker in the most important Italian conferences. He has also been recently appointed as C# Corner MVP.

About the Reviewer Ninaada is a Xamarin certified mobile developer with 10+ years of industry experience. He has extensively worked on Xamarin based projects for more than 6 years, across various domains and industries including Fortune 500 companies. He also is active in the xamarin community by contributing to GitHub and blogging occasionally. Currently, he is working as a Xamarin developer with Steer73. He also has a keen interest in nature and wildlife photography, which can be found on his social media pages. Find more at https://linktr.ee/ninaada

Acknowledgement I would first like to thank so much my wife, Angelica, who respects the time I need to write and that never stops to be supportive to me, always demonstrating to me so much love. I would like to then thank the team at BPB Publications for being so supportive. I have been authoring books for 15 years, but this was my first time with them, and the whole team made it simpler for me to approach to a different way of working. Special thanks to the amazing Arielle (https://imarielle.com), whose music has been my fuel during the many hours I spent writing. Finally, I would like to thank all the readers of this book and all those who have read other books or articles I wrote in the past years. Writing is a big effort, so you need a motivation to do it and having had good feedback over the years, is the right motivation for me to still write.

Preface This book covers mobile app development from the point of view of the developer that wants to target both iOS and Android systems from one codebase, using development tools from Microsoft. The book is intended for both the experienced and the novice developers, with a special, practical approach for those who want to start a new career as software developers in the mobile apps industry. Basic knowledge of the C# programming language is recommended, however the book introduces general programming and language-specific concepts that will be used across the book, so that also the novice developer can be familiar with all the discussed topics. The goal of the book is explaining how to build mobile apps from the ground up, focusing on all the necessary aspects: the user interface, the logic, the interaction with Web services, the consumption of data, the way an app should be architected for mobile devices. Special focus is also offered for those who want to start searching a new occupation as software developers with a Microsoft technical background. This book is divided into 15 chapters. The first four chapters introduce the reader into the world of software development with C#, Microsoft Visual Studio and .NET. Chapters from 5 to 13 are all technical chapters that cover the development of mobile apps with Xamarin, in a cross-platform approach. The last two chapters have specific focus on starting, building, and maintaining a career as a successful mobile developer. Below you find the details of each chapter. Chapter 1 describes why it is important to be a mobile app developer today, and why building apps in a cross-platform approach is the best choice especially for jobseekers. Chapter 2 describes how Microsoft jumped into the mobile app development ecosystem. An introduction to Xamarin is made, plus a you find a discussion about why choosing Xamarin as the development platform can be the key to success today.

Chapter 3 gives an introduction on the .NET technology (including the latest updates) and to Microsoft Visual Studio as a development environment Chapter 4 is intended to give absolute beginners a quick overview of the C# programming language to make them feel more comfortable with the development tools used across the book. Chapter 5 describes how to create a Xamarin solution with Microsoft Visual Studio, explaining how the code sharing strategy works to deliver apps to multiple OSes from the same codebase. Chapter 6 explains the fundamentals of user interface in mobile apps, and how to create adaptive and auto-sizing user interfaces using layouts. Chapter 7 chapter describes how to create the user interface of an app with the controls offered by Xamarin and how to manage user interaction with controls. Chapter 8 describes how to organize the user interface of an app in pages, the different kinds of pages and how navigation between pages works. Chapter 9 describes the concept of reusable resource and explains how to connect data objects to the user interface for automatic communication. It also explains how to use local SQLite databases to store, retrieve and display data. Chapter 10 discusses how to enrich the user interface of an app with brushes, shapes, and with media contents. Chapter 11 explains how to handle the different events of an app’s lifecycle and how to manage common requirements of mobile apps, such as network connection, battery level, local settings. Chapter 12 describes how to consume Web services in Xamarin projects, including Cloud services hosted on Azure. Chapter 13 describes how to access native iOS and Android APIs from Xamarin, pointing out how it is something to do only when the Xamarin and Xamarin.Essentials codebases do not have something that works cross- platform. It also describes how to implement customizations that are platform-specific. Chapter 14 helps you understand how to search for jobs that are related to mobile app development with Xamarin by making focused, appropriate job searches based on the reader’s experience after understanding the core

business of a company that is hiring. Chapter 15 provides advice on what a good approach is in order to keep a job in the mobile app development market including tips & tricks to work in a team and to stay up to date with technology.

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Table of Contents 1. The Importance of Mobile App Development Introduction Structure Objectives The importance of mobile app development Mobile devices and applications A brief history of modern mobile devices Mobile devices for everyone Mobile devices everywhere The importance of mobile apps for companies Career opportunities with mobile app development Making money with mobile app development Summarizing how a mobile system works The importance of a cross-platform approach Limitations of cross-platform code Application size and performance Understanding native applications Demystifying application performance issues Staying up to date with new devices and platforms Getting updates from Apple Getting updates from Google Getting news from Microsoft Conclusion Points to remember 2. Xamarin and Microsoft in the Mobile App Market Introduction Structure Objectives Xamarin as the app development framework Mobile App Development with Microsoft Skills Xamarin as a company

Introducing the mono project The transition to Xamarin Microsoft in the mobile app ecosystem The importance of Microsoft investments on Xamarin Improved productivity with Microsoft tools and services Understanding Xamarin and Xamarin.Forms Advantages of Xamarin.Forms Hints about .NET MAUI Installing and configuring the development tools System requirements for Xamarin System requirements on Windows System requirements on macOS Android and iOS Devices Installing and configuring Microsoft Visual Studio Selecting workloads Checking for individual components Configuring Android devices for developer mode Minimum macOS configuration Conclusion Questions Points to remember 3. Introducing .NET and Visual Studio Introduction Structure Objectives Introducing .NET Introducing the .NET framework for Windows Locating the .NET framework on disk The .NET framework architecture The Common Language Runtime (CLR) Compilers and the concept of Assembly Assemblies in .NET The Base Class Library From .NET Framework to .NET Core Advantages of .NET Core .NET 6: One .NET

Building applications with Visual Studio Signing in with a Microsoft account Synchronized settings Introducing the Start window Understanding projects and solutions Creating projects with C# Creating your first C# project Working with the Visual Studio IDE Working with tool windows Solution Explorer The Error List The Properties window The Output window Editing project properties Editing application settings Basic code editing features Syntax colorization Zooming the code editor Introducing IntelliSense Changing the Code Editor options Compiling, running, and debugging code Understanding configurations Running and Debugging Code Debugging your code Preparing the sample project for debugging Breakpoints and data tips Detecting and fixing runtime errors Conclusion Points to remember Key terms 4. The C# Programming Language Introduction Structure Objectives Understanding data types Meet the Common Type System

Clarifying value types and reference types .NET primitive types Declaring and consuming variables Clarifying the difference between value and reference types Common data operators Equals and Not Equals Operators Arithmetic operators Conversion operators Direct type conversion Converting types with the Convert class String conversion Logical operators Working with strings Checking for Null or Empty strings Concatenating strings Formatting strings Iterating objects Understanding loops Introducing the do loop Introducing the while loop Conditional code blocks The if conditional code block The switch conditional code block Introducing arrays Single-dimensional arrays Multi-dimensional arrays Jagged arrays Object-oriented programming (OOP) Understanding access modifiers Defining reference types with classes Storing information with fields and properties Running actions with methods Introducing constructors and static classes Defining derived types with inheritance Understanding interfaces and abstract classes Defining interfaces Implementing interfaces

Introducing abstract classes Organizing types within namespaces Accessing types within namespaces with using directives Defining value types with structures Assigning structures to variables Visibility of structures and their members Defining enumerations Using enumerations Implementing error handling Implementing events Advanced C# programming Generics and Nullable Types Working with Nullable types Language INtegrated Query (LINQ) Asynchronous programming Conclusion Suggested readings 5. Building Apps with Xamarin and Xamarin.Forms Introduction Structure Objective Understanding Xamarin.Android Projects Understanding the project structure Drawing and handling the user interface Configuring the App Manifest Debugging an Android app Configuring debugging and Build options Understanding Xamarin.iOS projects Understanding the project structure Handling the user interface Debugging an iOS app Understanding provisioning profiles and developer accounts Configuring App Package options Cross-platform projects with Xamarin.Forms Understanding the project structure Introducing XAML, App.xaml, and MainPage.xaml

Running and debugging apps Preparing apps for publication Preparing Android packages Preparing iOS packages Conclusion Points to remember Key terms 6. Organizing the User Interface with Layouts Introduction Structure Objectives Understanding the concept of layout Alignment and spacing options Understanding the visual tree .NET objects hierarchy Organizing the user interface Creating a Sample Project The StackLayout The FlexLayout The Grid Spacing, proportions and spans for rows and columns The AbsoluteLayout The RelativeLayout The ScrollView Controlling the ScrollView programmatically The Frame The ContentView Using a ContentView Styling the user interface with cascading style sheets Defining CSS styles as a XAML resource Consuming CSS files in XAML Creating and implementing CSS styles in C# Conclusion Points to remember Key terms