1 前言

        Lua基础语法 中系统介绍了 Lua 的语法体系，ToLua逻辑热更新 中介绍了 ToLua 的应用，本文将进一步介绍 Unity3D 中基于 xLua 实现逻辑热更新。

        逻辑热更新是指：在保持程序正常运行的情况下，在后台修改代码逻辑，修改完成并推送到运行主机上，主机无缝接入更新后的代码逻辑。Unity3D 中，基于 Lua 的逻辑热更新方案主要有 ToLua、xLua、uLua、sLua，本文将介绍 xLua 逻辑热更新方案。

        1）热更新的好处

• 不用浪费流量重新下载；
• 不用通过商店审核，版本迭代更加快捷；
• 不用重新安装，用户可以更快体验更新的内容

         2）xLua 插件下载

        xLua 是腾讯研发的 Unity3D 逻辑热更新方案，目前已开源，资源见：

• github：https://github.com/Tencent/xLua
• gitcode：https://gitcode.net/mirrors/Tencent/xlua

        3）xLua 插件导入

        将插件的 Assets 目录下的所有文件拷贝到项目的 Assets 目录下，如下：

        4）生成 Wrap 文件

        导入插件后，菜单栏会多一个 XLua 窗口，点击 Generate Code 会生成一些 Wrap 文件，生成路径见【Assets\XLua\Gen】，这些 Wrap 文件是 C# 与 Lua 沟通的桥梁。每次生成文件时，建议先点击下 Clear Generate Code，再点击 Generate Code。

        5）官方教程文档

        在【Assets\XLua\Doc\XLua教程.doc】中可以查阅官方教程文档，在线教程文档见：

• github：https://github.com/Tencent/xLua/tree/master/Assets/XLua/Doc/XLua教程.md
• gitcode：https://gitcode.net/mirrors/Tencent/xLua/tree/master/Assets/XLua/Doc/XLua教程.md

        6）官方Demo

2 xLua 应用

2.1 C# 中执行 Lua 代码串

        HelloWorld.cs

using UnityEngine;
using XLua;public class HelloWorld : MonoBehaviour {private void Start() {LuaEnv luaEnv = new LuaEnv();string luaStr = @"print('Hello World')CS.UnityEngine.Debug.Log('Hello World')";luaEnv.DoString(luaStr);luaEnv.Dispose();}
}

        运行如下：

        说明：第一个日志是 lua 打印的，所以有 "LUA: " 标识，第二个日志是 Lua 调用 C# 的 Debug 方法，所以没有 "LUA: " 标识。

2.2 C# 中调用 Lua 文件

        1）通过 Resources.Load 加载 lua 文件

         ScriptFromFile.cs

using UnityEngine;
using XLua;public class ScriptFromFile : MonoBehaviour {private void Start() {LuaEnv luaEnv = new LuaEnv();TextAsset textAsset = Resources.Load<TextAsset>("02/LuaScript.lua");luaEnv.DoString(textAsset.text);luaEnv.Dispose();}
}

        LuaScript.lua.txt

print("Load lua script")

        说明：LuaScript.lua.txt 文件放在 【Assets\Resources\02】目录下。因为 Resource 只支持有限的后缀，放 Resources 下的 lua 文件得加上 txt 后缀。

        2）通过内置 loader 加载 lua 文件

        ScriptFromFile.cs

using UnityEngine;
using XLua;public class ScriptFromFile : MonoBehaviour {private void Start() {LuaEnv luaEnv = new LuaEnv();luaEnv.DoString("require '02/LuaScript'");luaEnv.Dispose();}
}

        说明：require 实际上是调一个个的 loader 去加载，有一个成功就不再往下尝试，全失败则报文件找不到。 目前 xLua 除了原生的 loader 外，还添加了从 Resource 加载的 loader。因为 Resource 只支持有限的后缀，放 Resources 下的 lua 文件得加上 txt 后缀。 

        3）通过自定义 loader 加载 lua 文件

        ScriptFromFile.cs

using UnityEngine;
using XLua;
using System.IO;
using System.Text;public class ScriptFromFile : MonoBehaviour {private void Start() {LuaEnv luaEnv = new LuaEnv();luaEnv.AddLoader(MyLoader);luaEnv.DoString("require '02/LuaScript'");luaEnv.Dispose();}private byte[] MyLoader(ref string filePath) {string path = Application.dataPath + "/Resources/" + filePath + ".lua.txt";string txt = File.ReadAllText(path);return Encoding.UTF8.GetBytes(txt);}
}

2.3 C# 中调用 Lua 变量

        AccessVar.cs

using UnityEngine;
using XLua;public class AccessVar : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '03/LuaScript'");TestAccessVar();}private void TestAccessVar() {bool a = luaEnv.Global.Get<bool>("a");int b = luaEnv.Global.Get<int>("b");float c = luaEnv.Global.Get<float>("c");string d = luaEnv.Global.Get<string>("d");Debug.Log("a=" + a + ", b=" + b + ", c=" + c + ", d=" + d); // a=True, b=10, c=7.8, d=xxx}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        LuaScript.lua.txt

a = true
b = 10
c = 7.8
d = "xxx"

2.4 C# 中调用 Lua table

        1）通过自定义类映射 table

        AccessTable.cs

using UnityEngine;
using XLua;public class AccessTable : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '04/LuaScript'");TestAccessTable();}private void TestAccessTable() {Student stu = luaEnv.Global.Get<Student>("stu");Debug.Log("name=" + stu.name + ", age=" + stu.age); // name=zhangsan, age=23stu.name = "lisi";luaEnv.DoString("print(stu.name)"); // LUA: zhangsan}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}class Student {public string name;public int age;
}

        LuaScript.lua.txt

stu = {name = "zhangsan", age = 23, sex = 0, 1, 2, 3}

        说明：允许 table 中元素个数与自定义类中属性个数不一致，允许自定义类中属性顺序与 table 中元素顺序不一致；类中需要映射的属性名必须与 table 中相应元素名保持一致（大小写也必须一致）；修改映射类的属性值，不影响 table 中相应元素的值。

        2）通过自定义接口映射 table

        AccessTable.cs

using UnityEngine;
using XLua;public class AccessTable : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '04/LuaScript'");TestAccessTable();}private void TestAccessTable() {IStudent stu = luaEnv.Global.Get<IStudent>("stu");Debug.Log("name=" + stu.name + ", age=" + stu.age); // name=zhangsan, age=23stu.name = "lisi";luaEnv.DoString("print(stu.name)"); // LUA: lisistu.study("program"); // LUA: subject=programstu.raiseHand("right"); // LUA: hand=right}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}[CSharpCallLua]
public interface IStudent {public string name {get; set;}public int age {get; set;}public void study(string subject);public void raiseHand(string hand);
}

        说明：在运行脚本之前，需要先点击下 Clear Generate Code，再点击 Generate Code；允许 table 中元素个数与自定义接口中属性个数不一致，允许自定义接口中属性顺序与 table 中元素顺序不一致；接口中需要映射的属性名和方法名必须与 table 中相应元素名和函数名保持一致（大小写也必须一致）；修改映射接口的属性值，会影响 table 中相应元素的值。

        LuaScript.lua.txt

stu = {name = "zhangsan",age = 23,study = function(self, subject)print("subject="..subject)end
}--function stu.raiseHand(self, hand)
function stu:raiseHand(hand)print("hand="..hand)
end

        3）通过 Dictionary 映射 table

         AccessTable.cs

using System.Collections.Generic;
using UnityEngine;
using XLua;public class AccessTable : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '04/LuaScript'");TestAccessTable();}private void TestAccessTable() {Dictionary<string, object> stu = luaEnv.Global.Get<Dictionary<string, object>>("stu");Debug.Log("name=" + stu["name"] + ", age=" + stu["age"]); // name=zhangsan, age=23stu["name"] = "lisi";luaEnv.DoString("print(stu.name)"); // LUA: zhangsan}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        说明：修改映射 Dictionary 的元素值，不影响 table 中相应元素的值。

        LuaScript.lua.txt

stu = {name = "zhangsan", age = 23, "math", 2, true}

       4）通过 List 映射 table

         AccessTable.cs

using System.Collections.Generic;
using UnityEngine;
using XLua;public class AccessTable : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '04/LuaScript'");TestAccessTable();}private void TestAccessTable() {List<object> list = luaEnv.Global.Get<List<object>>("stu");string str = "";foreach(var item in list) {str += item + ", ";}Debug.Log(str); // math, 2, True, }private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        LuaScript.lua.txt

stu = {name = "zhangsan", age = 23, "math", 2, true}

        5）通过 LuaTable 映射 table

        AccessTable.cs

using UnityEngine;
using XLua;public class AccessTable : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '04/LuaScript'");TestAccessTable();}private void TestAccessTable() {LuaTable table = luaEnv.Global.Get<LuaTable>("stu");Debug.Log("name=" + table.Get<string>("name") + ", age=" + table.Get<int>("age")); // name=zhangsan, age=23table.Set<string, string>("name", "lisi");luaEnv.DoString("print(stu.name)"); // LUA: lisitable.Dispose();}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        说明：修改映射 LuaTable 的属性值，会影响 table 中相应元素的值 

        LuaScript.lua.txt

stu = {name = "zhangsan", age = 23, "math", 2, true}

2.5 C# 中调用 Lua 全局函数

        1）通过 delegate 映射 function

        AccessFunc.cs

using System;
using UnityEngine;
using XLua;public class AccessFunc : MonoBehaviour {private LuaEnv luaEnv;[CSharpCallLua] // 需要设置 public, 并且点击 Generate Codepublic delegate int MyFunc1(int arg1, int arg2);[CSharpCallLua] // 需要设置 public, 并且点击 Generate Codepublic delegate int MyFunc2(int arg1, int arg2, out int resOut);[CSharpCallLua] // 需要设置 public, 并且点击 Generate Codepublic delegate int MyFunc3(int arg1, int arg2, ref int resRef);private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '05/LuaScript'");TestAccessFunc1();TestAccessFunc2();TestAccessFunc3();TestAccessFunc4();}private void TestAccessFunc1() { // 测试无参函数Action func1 = luaEnv.Global.Get<Action>("func1");func1(); // LUA: func1}private void TestAccessFunc2() { // 测试有参函数Action<string> func2 = luaEnv.Global.Get<Action<string>>("func2");func2("xxx"); // LUA: func2, arg=xxx}private void TestAccessFunc3() { // 测试有返回值函数MyFunc1 func3 = luaEnv.Global.Get<MyFunc1>("func3");Debug.Log(func3(2, 3)); // 6}private void TestAccessFunc4() { // 测试有多返回值函数MyFunc1 func41 = luaEnv.Global.Get<MyFunc1>("func4");Debug.Log(func41(2, 3)); // 5int res, resOut;MyFunc2 func42 = luaEnv.Global.Get<MyFunc2>("func4");res = func42(2, 3, out resOut);Debug.Log("res=" + res + ", resOut=" + resOut); // res=5, resOut=-1int ans, resRef = 0;MyFunc3 func43 = luaEnv.Global.Get<MyFunc3>("func4");ans = func43(2, 3, ref resRef);Debug.Log("ans=" + ans + ", resRef=" + resRef); // res=5, resRef=-1}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        说明：Lua 函数支持多返回值，但 C# 函数不支持多返回值，要想让 C# 接收 Lua 函数的多个返回值，需要通过 out 或 ref 参数接收第 2 个及之后的返回值。

        LuaScript.lua.txt

--无参函数
function func1()print("func1")
end--有参函数
function func2(arg)print("func2, arg="..arg)
end--有返回值函数
function func3(a, b)return a * b
end--有多返回值函数
function func4(a, b)return a + b, a - b
end

        2）通过 LuaFunction 映射 function

        AccessFunc.cs 

using UnityEngine;
using XLua;public class AccessFunc : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '05/LuaScript'");TestAccessFunc1();TestAccessFunc2();TestAccessFunc3();TestAccessFunc4();}private void TestAccessFunc1() { // 测试无参函数LuaFunction func1 = luaEnv.Global.Get<LuaFunction>("func1");func1.Call(); // LUA: func1}private void TestAccessFunc2() { // 测试有参函数LuaFunction func2 = luaEnv.Global.Get<LuaFunction>("func2");func2.Call("xxx"); // LUA: func2, arg=xxx}private void TestAccessFunc3() { // 测试有返回值函数LuaFunction func3 = luaEnv.Global.Get<LuaFunction>("func3");object[] res = func3.Call(2, 3);Debug.Log(res[0]); // 6}private void TestAccessFunc4() { // 测试有多返回值函数LuaFunction func4 = luaEnv.Global.Get<LuaFunction>("func4");object[] res = func4.Call(2, 3);Debug.Log("res1=" + res[0] + ", res2=" + res[1]); // res1=5, res2=-1}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        说明：LuaScript.lua.txt 同第 1）节；LuaFunction 映射方式相较 delegate 方式，性能消耗较大。

2.6 Lua 中创建 GameObject 并获取和添加组件

        TestGameObject.cs

using UnityEngine;
using XLua;public class TestGameObject : MonoBehaviour {private LuaEnv luaEnv;private void Start() {luaEnv = new LuaEnv();luaEnv.DoString("require '06/LuaScript'");}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}

        LuaScript.lua.txt

local GameObject = CS.UnityEngine.GameObject
local PrimitiveType = CS.UnityEngine.PrimitiveType
local Color = CS.UnityEngine.Color
local Rigidbody = CS.UnityEngine.RigidbodyGameObject("xxx") --创建空对象
go = GameObject.CreatePrimitive(PrimitiveType.Cube)
go:GetComponent("MeshRenderer").sharedMaterial.color = Color.red
rigidbody = go:AddComponent(typeof(Rigidbody))
rigidbody.mass = 1000

2.7 Lua 中访问 C# 自定义类

        TestSelfClass.cs

using UnityEngine;
using XLua;public class TestSelfClass : MonoBehaviour {private LuaEnv luaEnv;private void Awake() {luaEnv = new LuaEnv();luaEnv.DoString("require '07/LuaScript'");}private void OnApplicationQuit() {luaEnv.Dispose();luaEnv = null;}
}[LuaCallCSharp] // 需要点击 Generate Code
class Person {public string name;public int age;public Person(string name, int age) {this.name = name;this.age = age;}public void Run() {Debug.Log("run");}public void Eat(string fruit) {Debug.Log("eat " + fruit);}public override string ToString() {return "name=" + name + ", age=" + age;}
}

        LuaScript.lua.txt

local Person = CS.Personperson = Person("zhangsan", 23)
print("name="..person.name..", age="..person.age) -- LUA: name=zhangsan, age=23
print(person:ToString()) -- LUA: name=zhangsan, age=23
person:Run() -- run
person:Eat("aple") -- eat aple

3 Lua Hook MonoBehaviour 生命周期方法

        MonoBehaviour 生命周期方法见→MonoBehaviour的生命周期。

        TestLife.cs

using System;
using System.Collections.Generic;
using UnityEngine;
using XLua;public class TestLife : MonoBehaviour {private LuaEnv luaEnv;private Dictionary<string, Action> func;private void Awake() {luaEnv = new LuaEnv();luaEnv.DoString("require '08/LuaScript'");GetFunc();CallFunc("awake");}private void OnEnable() {CallFunc("onEnable");}private void Start() {CallFunc("start");}private void Update() {CallFunc("update");}private void OnDisable() {CallFunc("onDisable");}private void OnDestroy() {CallFunc("onDestroy");}private void GetFunc() {func = new Dictionary<string, Action>();AddFunc("awake");AddFunc("onEnable");AddFunc("start");AddFunc("update");AddFunc("onDisable");AddFunc("onDestroy");}private void AddFunc(string funcName) {Action fun = luaEnv.Global.Get<Action>(funcName);if (fun != null) {func.Add(funcName, fun);}}private void CallFunc(string funcName) {if (func.ContainsKey(funcName)) {Action fun = func[funcName];fun();}}private void OnApplicationQuit() {func.Clear();func = null;luaEnv.Dispose();luaEnv = null;}
}

        LuaScript.lua.txt 

function awake()print("awake")
endfunction onEnable()print("onEnable")
endfunction start()print("start")
endfunction update()print("update")
endfunction onDisable()print("onDisable")
endfunction onDestroy()print("onDestroy")
end