Multiplatform development

Compiler Definitions

Compiler definitions run platform specific code. Using them you can make small differences between various platforms.

Trigger Game Center achievements on apple devices and google play achievements on Android devices.
Change the icons in menus (windows logo in windows, Linux penguin in Linux).
Possibly have platform specific mechanics depending on the platform.
And much more…

void Update(){

#if UNITY_IPHONE //code here is only called when running on iPhone #endif

#if UNITY_STANDALONE_WIN && !UNITY_EDITOR //code here is only ran in a unity game running on windows outside of the editor #endif

//other code that will be ran regardless of platform

}

A complete list of Unity compiler definitions can be found here

Organizing platform specific methods to partial classes

Partial classes provide a clean way to separate core logic of your scripts from platform specific methods.

Partial classes and methods are marked with the keyword partial. This signals the compiler to leave the class “open” and look in other files for the rest of the implementation.

// ExampleClass.cs
using UnityEngine;

public partial class ExampleClass : MonoBehaviour
{
    partial void PlatformSpecificMethod();

    void OnEnable()
    {
        PlatformSpecificMethod();
    }
}

Now we can create files for our platform specific scripts that implement the partial method. Partial methods can have parameters (also ref) but must return void.

// ExampleClass.Iphone.cs

#if UNITY_IPHONE
using UnityEngine;

public partial class ExampleClass
{
    partial void PlatformSpecificMethod()
    {
        Debug.Log("I am an iPhone");
    }
}
#endif

// ExampleClass.Android.cs

#if UNITY_ANDROID
using UnityEngine;

public partial class ExampleClass
{
    partial void PlatformSpecificMethod()
    {
        Debug.Log("I am an Android");
    }
}
#endif

If a partial method is not implemented, the compiler will omit the call.

Tip: This pattern is useful when creating Editor specific methods as well.