Maui-Xamarin.Forms

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Xamarin.Forms

xamarin/Xamarin.Forms: Xamarin.Forms Official Home (github.com)

Xamarin.Forms provides a way to quickly build native apps for iOS, Android, Windows and macOS, completely in C#.

Read more about the platform at https://www.xamarin.com/forms.

Getting Started

For both methods underneath you will have to add this NuGet feed for the build to succeed. See this documentation page to find out how.

Windows

Install Visual Studio 2019+

VS 2019+ is required for developing Xamarin.Forms. If you do not already have it installed, you can download it here. VS 2019+ Community is completely free. If you are installing VS 2019+ for the first time, select the "Custom" installation type and select the following from the features list to install:

  • .NET desktop development
    • Individual Components > .NET > .NET Framework 4.6.1 SDK, .NET Framework 4.6.1 targeting pack, .NET Framework 4.7.2 SDK, .NET Framework 4.7.2 targeting pack.
  • Universal Windows Platform Development
  • Mobile Development with .NET
    • Individual Components > Development Activities > Xamarin Remoted Simulator
    • If you're not using Hyper-V Individual Components > Emulators > Hyper-V Intel Hardware Accelerated Execution Manager (HAXM)
  • Most current SDK version of .NET Core

The Android 10.0 API 29 SDK and Android 9.0 API 28 SDK are required for developing Xamarin.Forms. They can be installed by using the Xamarin Android SDK Manager.

We also recommend installing Xamarin Android Device Manager. This will use the HAXM tools installed above and allow you to configure Android Virtual Devices (AVDs) that emulate Android devices. If you already have VS 2019+ installed, you can verify that these features are installed by modifying the VS 2019+ installation via the Visual Studio Installer.

Provisioning script

If you are getting errors about missing SDKs, you can run our provisioning script. Note that it can take some time to run the whole script. To better understand how the script works, feel free to check out our build.cake file.

  • On CMD

    build.cmd -Target provision

  • On Powershell

    ./build.ps1 -Target provision

    NOTE: If you encounter an error saying build.ps1 is not digitally signed, open Powershell as an administrator and resolve by running Set-ExecutionPolicy RemoteSigned first.

  • On CMD/Powershell/sh (New! More info here)

    dotnet tool install Cake.Tool -g
dotnet cake --target=provision

Mac

Install Visual Studio for Mac 2019

If you do not already have it installed, instructions to download and setup can be found here.

Because of current Multi-Targeting limitations with Visual Studio for Mac you will need to manually build/restore some projects before you are able to work on the Xamarin Forms solution.

Here are a few different options we've put together to help make this process easier

  • Branches 3.5+ come with a Cake script target that you can use to build and open VSMac

    ./build.sh --target vsmac

    OR as mentioned above in the Windows section about provisioning, you can also use the new Cake.Tool

    dotnet tool install Cake.Tool -g
dotnet cake --target=provision

  • When working on an earlier branch that does not have the cake scripts, you can use the following build.sh script

  • If you don't want to run any scripts:

    • Open Xamarin.Forms.sln
    • Wait for VSMAC to finish restoring all projects
    • from the command line run:
      • msbuild Xamarin.Forms.Build.Tasks/Xamarin.Forms.Build.Tasks.csproj
    • Now you should be able to run and deploy everything. The only reason you would need to do this process again is if you clean the solution folder or delete the bin/obj folders that are part of the Xamarin.Forms.Build.Tasks.csproj
Solution Configuration

Upon opening the Xamarin.Forms solution, you will find that there are a number of errors and warnings under the Error List pane; you can resolve this by changing the filter of Build + IntelliSense to Build Only. At this point, you should be able to successfully build the solution.

By default, the Xamarin.Forms.Controls project does not have a configuration for various API keys to access certain features on each platform (e.g. maps). When building the solution for the first time, a controlgallery.config file will be generated inside that project, which looks like this:

UWPMapsAuthKey:

If you aren't working with maps, you can ignore this. If you want to work with maps, you will have to obtain your own API keys for each of these services, inserted directly after the identifier (e.g. UWPMapsAuthKey:abcdefghijklmnopqrstuvwxyz). You can find out how to obtain each of these as follows:

Due to the way that Android works, the maps API key cannot be injected at runtime. As a result, you will have to add this key to the MapsKey.cs file under Xamarin.Forms.ControlGallery.Android/Properties:

[assembly: Android.App.MetaData("com.google.android.maps.v2.API_KEY", Value = "INSERT_KEY_HERE")]

You can find out how to obtain a Google Maps API key here.

Build from the Command line

Make sure you have nuget.exe 4.0 or above and the latest .NET Core SDK. On macOS you should specify the platform in the msbuild command (/p:Platform=iPhoneSimulator)

msbuild /restore Xamarin.Forms.sln

UI Tests

Run Android UI Tests

Depending on your environment setup, you might need to configure a few things before being able to debug / run UI tests, especially on Windows.

  • If you receive an error about ANDROID_HOME, please make sure to set your environment variable to the Android SDK directory (e.g. C:\Program Files (x86)\Android\android-sdk).
  • If you receive an error about JAVA_HOME, please install the latest Java JDK and set your environment variable to the JDK directory (e.g. C:\Program Files\Java\jdk-13).
  • If you receive an error about a missing ApkFile, please generate an APK file for Xamarin.Forms.ControlGallery.Android. The easiest way to do this is to right click the project and select "Deploy". Note that if you rebuild the solution, you might lose the APK and will need to generate it again.

After these steps are taken care of, you should be good to go. You can see all UI tests in Test Explorer, search them for your own convenience, and quickly run individual tests.

Run UWP UI Tests

To run the UWP UI Tests:

  1. Install and run the Windows Application Driver.
  2. Launch the Xamarin.Forms.ControlGallery.WindowsUniversal project to install the ControlGallery application onto your system.

You should now be able to run any of the UWP UI Tests.

Coding Style

We follow the style used by the .NET Foundation, with a few exceptions:

  • We do not use the private keyword as it is the default accessibility level in C#.
  • We use hard tabs over spaces. You can change this setting in Visual Studio for Windows via Tools > Options and navigating to Text Editor > C# and selecting the "Keep tabs" radio option. In Visual Studio for Mac it's set via preferences in Source Code > Code Formatting > C# source code and disabling the checkbox for Convert tabs to spaces.
  • Lines should be limited to a max of 120 characters (or as close as possible within reason). This may be set in Visual Studio for Mac via preferences in Source Code > Code Formatting > C# source code and changing the Desired file width to 120.