Write Unity IOS Module to Swift Code

How to call Unity methods

Unity interface functions are defined in UnityInterface.h in an Xcode project built by Unity. This header file is imported into UnitySwift-Bridging-Header.h, so you can call functions directly in your Swift codes.

To call Unity methods, use the function UnitySendMessage

as shown below:

    //  Example.swift

import Foundation

class Example : NSObject {
    static func callUnityMethod(_ message: String) {
        // Call a method on a specified GameObject.
        UnitySendMessage("CallbackTarget", "OnCallFromSwift", message)
    }
}

      

        
        
        
      

    

How to access Swift classes from Unity

Step 1. Create Swift Classes.

//  Example.swift

import Foundation

class Example : NSObject {
    static func swiftMethod(_ message: String) {
        print("\(#function) is called with message: \(message)")
    }
}

      

        
        
        
      

    

Step 2. Include "unityswift-Swift.h" and define C functions to wrap Swift classes in a .mm (Objective-C ++) file.

//  Example.mm

#import <Foundation/Foundation.h>
#import "unityswift-Swift.h"    // Required
                                // This header file is generated automatically when Xcode build runs.

extern "C" {
    void _ex_callSwiftMethod(const char *message) {
        // You can access Swift classes directly here.
        [Example swiftMethod:[NSString stringWithUTF8String:message]];
    }
}

      

        
        
        
      

    

Step 3: Create an interface class to call exported C functions from C #.

// Example.cs

using System.Runtime.InteropServices;

public class Example {
    #if UNITY_IOS && !UNITY_EDITOR
    [DllImport("__Internal")]
    private static extern void _ex_callSwiftMethod(string message);
    #endif

    // Use this method to call Example.swiftMethod() in Example.swift
    // from other C# classes.
    public static void CallSwiftMethod(string message) {
        #if UNITY_IOS && !UNITY_EDITOR
        _ex_callSwiftMethod(message);
        #endif
    }
}

      

        
        
        
      

    

Step 4. Call the method from your C # code.

Example.CallSwiftMethod("Hello, Swift!");

      

        
        
        
      

    

The file names UnitySwift-Bridging-Header.h and unityswift-Swift.h are defined in the "Objective-C Bridging Header" entry and the "Objective-C Generated interface header name" entry in the build settings. These settings and other settings for the Swift compiler are automatically set by PostProcesser when Unity builds .

Requirements

iOS 7 or later

Compatibility

Unity 5.3.5f1 Xcode 7.3.1