Appendix: Going Mobile

Tips to take the bat and ball game from this guide to Android and iOS devices.

This appendix gives short tips to play the bat and ball game from Step 6 on Android and iOS devices. It is not a full guide to mobile development.

Install the mobile workloads

A workload adds support for a platform to the .NET SDK. To build for Android or iOS, install the workload for each platform:

dotnet workload install android
dotnet workload install ios

Important

Install the workload for each platform onto your developer machine. If a workload is not installed, the full solution will not build. These are available for all projects, the workload simply enables your machine to build for that platform with .NET.

You will also need some additional tools from the vendors for each platform:

Android: You also need the Android SDK. Visual Studio and Rider can install it for you. For other methods, refer to Install the .NET for Android dependencies.
iOS: To build and run an iOS game, you must have a Mac with Xcode installed. To install a game on an iPhone or iPad, you also need an Apple developer account. (You can build an iOS project on Windows, but you cannot build or run it).

Add the mobile platforms to your project

The template adds platform projects only when you create a project. To add Android and iOS to the game from this guide:

Create a new project that includes the mobile platforms to a separate folder (DO NOT try this command targeting the existing project folder, as it will either not work or overwrite files):
```
dotnet new monogame -n BatAndBall --Platforms vk dx12 android ios
```
Copy these files from your old project to the new project:
- Source/Game1.cs.
- All the files in Content/Assets.
- Content/Builder/Builder.cs.
Build the full solution once.

Note

Alternatively, you can copy the new "Platforms" folders, and the platform "resources" folders to your existing project and then update the .sln (or .slnx if you have migrated it) to include the new platforms. Everything else should just work.

The game code and the content do not change for each platform. Only the projects in the Platforms folder are different.

Tip

When you start a new game, select all the platforms that you think you will need. It is easier to delete a platform than to add one. To delete a platform, delete its folder in Platforms and remove the project from the solution.

Add touch input

Phones and tablets do not have a keyboard. To move the bats with touch, you need to read the TouchPanel state in Update.

At the top of Game1.cs, add this line:

using Microsoft.Xna.Framework.Input.Touch;

In Update, add this code below the two lines that move the bats with the keyboard, and above the two MathHelper.Clamp lines:

// Move each bat to a finger on its side of the screen.
foreach (TouchLocation touch in TouchPanel.GetState())
{
    float touchY = touch.Position.Y - _batTexture.Height / 2f;
    if (touch.Position.X < screen.Width / 2)
    {
        _leftBat.Y = touchY;
    }
    else
    {
        _rightBat.Y = touchY;
    }
}

TouchPanel.GetState gives one TouchLocation for each finger on the screen. A finger on the left half of the screen moves the left bat. A finger on the right half moves the right bat. Thus, two players can play on one device. The MathHelper.Clamp lines below this code keep the bats on the screen.

The keyboard code stays in the game, so the desktop versions still operate with the keyboard.

Screen size and orientation

The game uses GraphicsDevice.Viewport.Bounds for all positions. Thus, it adapts to the screen size of each device.
The Android project shows the game in landscape orientation. This is set by ScreenOrientation.SensorLandscape in Platforms/Android/MainActivity.cs.
The iOS project also shows the game in landscape orientation. This is set by UISupportedInterfaceOrientations in Resources/iOS/Info.plist.

Stop the game

iOS does not let an app close itself. The #if !__IOS__ lines in Update remove the exit code from iOS builds.
On Android, the Back button of the device is the same as the Back button of a gamepad. Thus, the template exit code closes the game.

Run the game on a device

Visual Studio: Install the .NET Multi-platform App UI development workload. Then, select the Android or iOS project, select a device or an emulator in the toolbar, and press F5.
Visual Studio Code: Install the .NET MAUI extension. Then, select a device in the status bar, and run the Android or iOS launch configuration.
Rider: Select the run configuration for the Android or iOS project, then select a device.

On a physical Android device, enable Developer options and USB debugging before you connect it to your computer.

Before you publish

Before you publish your game to a store, change the identity of your game in Resources/Identity.props:

ApplicationId: a unique name for your game, for example com.yourname.batandball. This becomes the Android package name and the iOS bundle identifier.
ApplicationVersion and ApplicationDisplayVersion: the version of your game. Increase ApplicationVersion for each store submission.

The Android name under the launcher icon comes from Resources/Android/Values/strings.xml.

For more information, refer to these pages:

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