Xamarin 4.x Cross-Platform Application Development: Develop powerful cross-platform applications with Xamarin, Third Edition

Xamarin has developed three core products for developing cross-platform applications: Xamarin Studio, Xamarin.iOS, and Xamarin.Android. Xamarin Studio is a C# IDE, while Xamarin.iOS and Xamarin.Android are the core tooling that enable C# applications to run on iOS and Android, respectively. These tools allow developers to leverage the native libraries on iOS and Android, and are built on the Mono runtime.

Mono, an open source implementation of C# and the .NET framework, was originally developed by Novell to be used on Linux operating systems. Since iOS and Android are similarly based on Linux, Novell was able to develop MonoTouch and Mono for Android as products to target the new mobile platforms. Shortly after their release, a larger company acquired Novell, and the Mono team left to form a new company aimed primarily at mobile development. Xamarin was founded to focus on these tools for developing with C# on iOS and Android.

Getting a development machine ready for cross-platform application development can take some time. And to make matters worse, Apple and Google both have their own requirements for development on their respective platforms. If you plan on developing on Windows with Visual Studio, your setup will be a bit different than on Mac OS X. Keep in mind that iOS development on Windows requires a Mac on your local network. Let's go over what needs to be installed on your machine.

The building blocks for Xamarin development on Mac OS X are as follows:

The required software for Xamarin development on Windows are as follows:

Each of these will take some time to download and install. If you can access a fast Internet connection, it will help speed up the installation and setup process. With everything ready to go, let's move ahead step by step and, hopefully, we can skip a few dead ends you might otherwise run into.

To make things progress more smoothly, let's start off by installing Xcode for Mac. Along with Apple's IDE, it will also install the most commonly-used developer tools on the Mac. Make sure you have at least OS X 10.10 (Yosemite), and locate Xcode in the App Store, as shown in the following screenshot:

This will take quite some time to download and install. I'd recommend taking the time to enjoy a nice cup of coffee or working on another project side-by-side.

Installing Xcode installs the iOS SDK, which is a requirement for iOS development in general. As a restriction from Apple, the iOS SDK can only run on a Mac. Xamarin has done everything possible to make sure they follow Apple's guidelines for iOS, such as dynamic code generation. Xamarin's tools also leverage features of Xcode wherever possible to avoid reinventing the wheel.

After installing Xcode, there are several other dependencies that need to be installed, prior to developing with Xamarin's tooling. Luckily, Xamarin has improved the experience by creating a simple all-in-one installer.

Install Xamarin by performing the following steps:

The Xamarin installer will download and install prerequisites such as the Mono runtime, Java, the Android SDK (including the Android emulator and tools), and everything else you need to be up and running.

You will end up with something similar to what is shown in the following screenshot, and we can move on to conquer bigger topics in cross-platform development:

The Android emulator has historically been known to be sluggish compared to developing on a physical device. To help solve this issue, Google has produced an x86 emulator that supports hardware acceleration on desktop computers. It isn't installed by default in the Android Virtual Device (AVD) Manager, so let's set that up.

The x86 Android emulator can be installed by performing the following steps:

The emulator will take some time to start up, so it is a good idea to leave the emulator running while working on an Android project. Xamarin is using the standard Android tools here, so even Java developers feel the pain of the sluggish emulator. If everything starts properly, you will see an Android boot screen followed by a virtual Android device ready for deploying applications from Xamarin Studio, as shown in the following screenshot:

There are many options out there for Android emulators, such as Genymotion or Visual Studio Android Emulator. Using Xamarin will not limit your choices in Android emulators, so feel free to experiment if the default Android emulator isn't working for you.

Since Microsoft acquired Xamarin in 2016, Xamarin is included with any edition of Visual Studio. The editions are as follows:

When first setting up a Windows PC for Xamarin development, there are two choices to consider. If you already have Visual Studio, then you can merely use the Xamarin installer to add the necessary Visual Studio extensions and item templates to your existing installation. If you do not have Visual Studio installed yet, then there is simply an option in the Visual Studio 2015 installer for installing Xamarin.

If you want to install from the Visual Studio installer:

Your installer should look something like this before you click Next:

The second option for installing Xamarin is from Xamarin's website:

The Xamarin installer is a very similar experience to what you see on Mac OS X, and should be very straightforward. It will add Xamarin to an existing Visual Studio installation if needed and install Xamarin Studio.

iOS development requires Xcode running on Mac OS X. Luckily, Xamarin has made remote development possible from a Windows PC.

To connect your PC to a Mac:

When connected, you should see something like the following screenshot:

Once connected, you can simply press the play button to debug your project against the iOS simulator or an iOS device of your choice. All the features in Visual Studio you expect will also work with iOS development: break points, mouse-over evaluation, add watch, and so on.

To deploy to an iOS device, Apple requires membership to its iOS Developer Program. Membership is $99 USD per year and gives you access to deploy 200 devices for development purposes. You also get access to test servers for implementing more advanced iOS features such as in-app purchases, push notifications, and iOS Game Center. Testing your Xamarin.iOS applications on a physical device is important, so I recommend that you get an account prior to starting iOS development. Performance is very different in a simulator running on your desktop versus a real mobile device. There are also a few Xamarin-specific optimizations that only occur when running on a real device. We'll fully cover the reasons for testing your apps on devices in later chapters.

Signing up for the iOS developer program can be performed through the following steps:

You should receive an e-mail that looks something like the following screenshot within two business days:

From here, you can continue setting up your account:

When all is said and done, your Agreements, Tax, and Banking section should look something like the following screenshot:

With your iOS developer account successfully registered, you will now be able to deploy to iOS devices and publish your apps to the Apple App Store.

Unlike iOS, deploying your applications to Android devices is free and only requires a few changes in your device settings. A Google Play developer account has only a one-time fee of $25 and doesn't have to be renewed each year. However, just like iOS, you will need a Google Play account to develop in-app purchases, push notifications, or Google Play Game Services. I would recommend setting up an account ahead of time if you inevitably plan on submitting an app to Google Play or need to implement one of these features.

To register as a developer for Google Play, perform the following steps:

If you get everything filled out correctly, you will end up with the following Google Play Developer Console:

If you plan on selling paid apps or in-app purchases, at this point, I would recommend setting up your Google Merchant Account. This will enable Google to pay you the proceeds toward your app sales by applying the appropriate tax laws in your country. If setting this up for your company, I would recommend getting the assistance of your company's accountant or bookkeeper.

The following are the steps to set up a Google Merchant Account:

When done, you will notice that the help tip for setting up a merchant account is now missing from the developer console, as shown in the following screenshot:

At this point, one would think our account would be fully set up, but there is one more crucial step prior to being able to sell apps: we have to enter the banking information.

Setting up banking for your Google Merchant Account can be performed with the following steps:

Your Google Merchant Account is also the place where you can cancel or refund customer orders. Google Play is different from the iOS App Store in that all customer issues are directed to the developers.

In this chapter, we discussed Xamarin's core products for developing Android and iOS applications in C# whether you are using Mac OS X or a Windows PC. We installed Xcode and then ran the Xamarin all-in-one installer, which installs Java, the Android SDK, Xamarin Studio, Xamarin.iOS, and Xamarin.Android. On Windows, we set up Xamarin for use inside Visual Studio and connected a Mac on our local network for iOS development. We set up the x86 Android emulator for a faster, more fluid experience when debugging applications. Finally, we set up iOS and Google Play developer accounts for distributing our applications.

In this chapter, you should have acquired everything you need to get started on building cross-platform applications with Xamarin. Your development computer should be ready to go and you should have all the native SDKs installed and ready for creating the next great app to take the world by storm.

The concepts in this chapter will set us up for more advanced topics, which will require the proper software installed as well as developer accounts with Apple and Google. We will be deploying applications to real devices and implementing more advanced features such as push notifications. In the following chapter, we'll create our first iOS and Android application and cover the basics of each platform.