unity微信小游戏实现JS与C#的通信

需求背景

最近微信广告要求微信小游戏必须接入广告归因js-sdk, 但我们的unity开发的微信小游戏游戏逻辑都在c#实现, 所以需要JS与C#的通信, 全网搜索之前还没有其他同学对此做过总结分享, 借此水一篇小作文

C#发消息给JS

参考unity官方文档

js库代码

在unity工程Plugins文件夹里创建wx.jslib

mergeInto(LibraryManager.library, {
    CSharpSendMsgToJS: function (msgPtr) {
        // 注意window系统jslib文件不能添加中文注释, 否则会打包失败
        // 用于将 Unity 中的字符串指针转换为 JavaScript 字符串
        var msg = _WXPointer_stringify_adaptor(msgPtr);
        console.log(msg);
        // 在js里创建一个方法接收c#的消息
        window.handleReceiveMsgFromCSharp(msg);
    }
});

c#桥接代码

public class Bridge : MonoBehaviour
{
    private static Bridge _instance;


    [DllImport("__Internal")]
    private static extern void CSharpSendMsgToJS(string msg);

    public void JSSendMsgToCSharp(string msg)
    {
        Debug.Log($"CSharp收到了JS发来的消息: {msg}");
    }

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterSceneLoad)]
    public static void Init()
    {
        if (_instance == null)
        {
            GameObject go = GameObject.Find("WXBridge");
            if (go == null)
            {
                go = new GameObject("WXBridge");
                DontDestroyOnLoad(go);
            }
            _instance = go.AddComponent<Bridge>();
        }
        Dictionary<string, object> data = new Dictionary<string, object>();
        data.Add("msg", "hello form CSharp");
        CSharpSendMsgToJS(JsonConvert.SerializeObject(data));
    }

}

JS发消息给C#

function sendMsgToCSharp(data) {
	GameGlobal.Module.SendMessage(
           // 注意此字符串必须与GameObject的名称保持一致
		'WXBridge',
		'JSSendMsgToCSharp',
		JSON.stringify(data)
	)
}

GameGlobal.Module.SendMessage方法的实现在unity打包的微信小游戏工程里根目录下的webgl.wasm.framework.unityweb.js里

function SendMessage(gameObject, func, param) {
        var func_cstr = stringToNewUTF8(func);
        var gameObject_cstr = stringToNewUTF8(gameObject);
        var param_cstr = 0;
        try {
            if (param === undefined) _SendMessage(gameObject_cstr, func_cstr);
            else if (typeof param === "string") {
                param_cstr = stringToNewUTF8(param);
                _SendMessageString(gameObject_cstr, func_cstr, param_cstr);
            } else if (typeof param === "number") _SendMessageFloat(gameObject_cstr, func_cstr, param);
            else throw "" + param + " is does not have a type which is supported by SendMessage.";
        } finally {
            _free(param_cstr);
            _free(gameObject_cstr);
            _free(func_cstr);
        }
    }