This page describes Native Code Plugins for the iOS platform.
Define your extern method in the C# file as follows:
[DllImport ("__Internal")]
private static extern float FooPluginFunction();
Set the editor to the iOS build target.
Add your native code source files to the generated Xcode project’s Classes folder (this folder is not overwritten when the project is updated, but don’t forget to backup your native code).
If you are using C++ (.cpp) or Objective-C++ (.mm) to implement the plugin you must ensure the functions are declared with C linkage to avoid name mangling issues.
extern "C" {
float FooPluginFunction();
}
Plugins written in C or Objective-C do not need this since these languages do not use name-mangling.
iOS native plugins can be called only when deployed on the actual device, so it is recommended to wrap all native code methods with an additional C# code layer. This code should check Application.platform and call native methods only when the app is running on the device; dummy values can be returned when the app runs in the Editor. See the Bonjour browser sample application for an example.
Unity iOS supports limited native-to-managed callback functionality via UnitySendMessage:
UnitySendMessage("GameObjectName1", "MethodName1", "Message to send");
This function has three parameters: the name of the target GameObject, the script method to call on that object and the message string to pass to the called method.
Known limitations:
function MethodName(message:string)
Unity iOS supports automated plugin integration in a limited way. All files with extensions .a,.m,.mm,.c,.cpp located in the Assets\Plugins\iOS folder will be merged into the generated Xcode project automatically. However, merging is done by symlinking files from Assets\Plugins\iOS to the final destination, which might affect some workflows. The .h files are not included in the Xcode project tree, but they appear on the destination file system, thus allowing compilation of .m/.mm/.c/.cpp files.
Note: Subfolders are currently not supported.
A simple example of the use of a native code plugin can be found here
This sample demonstrates how objective-C code can be invoked from a Unity iOS application. This application implements a very simple Bonjour client. The application consists of a Unity iOS project (Plugins\Bonjour.cs is the C# interface to the native code, while BonjourTest.cs is the script that implements the application logic) and native code (Assets\Code) that should be added to the built Xcode project.
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