[游戏开发]cocos creator jsb2.0手动绑定过程

在打包原生包的时候js层想调用c++层，但是没有对应的实现需要自己扩展自己的jsb,官方有两种绑定方式：手动绑定和自动绑定，这里着重介绍手动绑定：

首先找到cocos creator自带的c++层的源码，复制出来然后自定义引擎，这里我也不细讲了，感兴趣的可以去看看官网的文档。

将c++层的jswrap 主要的目录如下：

?找到手动manual文件夹下在这里创建自己的c++文件就可以了

?这里作为测试我创建了文件 jsb_test.hpp jsb_test.cpp

test.hpp:

#pragma once

namespace se
{
    class Object;
    
}

bool register_all_testio(se::Object* obj);

test.cpp:

#include "jsb_test.hpp"
#include "cocos/scripting/js-bindings/manual/jsb_conversions.hpp"
#include "cocos/scripting/js-bindings/jswrapper/SeApi.h"
#include "stdio.h"
#include "test.hpp"
#include<iostream>

/**
 * 整形：
 * short 2字节 -2^15 ~ 2^15 - 1  -32768 ~ 32767 short a = 32768 => a = -32768;
 * int 4字节
 * long 4字节
 * long long 8字节
 * 
 * 实型
 * float 4字节
 * double 8字节
 * 
 * 字符型
 * char 1字节
 * 
 * 
*/

using namespace std;
static se::Object* __jsb_test_proto = nullptr;
static se::Class* __jsb_test_class = nullptr;

static bool jsb_Test(se::State &s) {
    // char* a = "ads";
    CC_UNUSED std::string ok = "";
    std::string result = "测试指令";
    ok = std_string_to_seval(result,&s.rval());

    return true;
}
SE_BIND_FUNC(jsb_Test);

static bool jsb_Console(se::State &s) {
    cout << s.args()[0].toString() << endl;
    return true;
}
SE_BIND_FUNC(jsb_Console);

// 析构函数
static bool jsb_finalize(se::State& s) {
    cout << "析构函数调用" << endl;
    ns::TestJsb* obj = (ns::TestJsb*)s.nativeThisObject();
    delete obj;
    return true;
}
// 绑定析构函数
SE_BIND_FINALIZE_FUNC(jsb_finalize);

// 构造函数
static bool jsb_constructor(se::State& s) {
    cout << "构造函数调用" << endl;
    ns::TestJsb* obj = new ns::TestJsb();
    s.thisObject()->setPrivateData(obj);
    return true;
}
// 绑定构造函数
SE_BIND_CTOR(jsb_constructor, __jsb_test_class,jsb_finalize);

// get方法
static bool jsb_getName(se::State& s) {
    // 拿到nativeObject 的属性name值
    ns::TestJsb* obj = (ns::TestJsb*)s.nativeThisObject();
    cout << "name is " << obj->getName() << endl;
    s.rval().setString(obj->getName());
    return true;
} 
SE_BIND_PROP_GET(jsb_getName);

// set方法
static bool jsb_setName(se::State& s) {
    std::cout << "设置名字" << std::endl;
    cout << "参数是：" << s.args()[0].toString() << endl;
    ns::TestJsb* obj = (ns::TestJsb*)s.nativeThisObject();
    
    const std::string& a0 = s.args()[0].toString();
    obj->setName(a0.c_str());
    
    cout << "设置名字完毕" << endl;
    return true;
}
SE_BIND_PROP_SET(jsb_setName);

static bool jsb_staticFunction(se::State& s) {
    ns::TestJsb::goHome();
    return true;
    
}
SE_BIND_FUNC(jsb_staticFunction);


// 回调函数
static bool jsb_callback(se::State& s) {
    const auto& args = s.args();
    int argc = (int)args.size();
    if(argc == 0) {
        cout << "参数个数错误" << endl;
        return false;
    }
    
    ns::TestJsb* cobj = (ns::TestJsb*)s.nativeThisObject();
    se::Value jsFunc = args[0];
    se::Value jsTarget = argc > 1 ? args[1] : se::Value::Undefined;
    
    if(jsFunc.isNullOrUndefined()) {
        cobj->setCallback(nullptr);
    } else {
        assert(jsFunc.isObject() && jsFunc.toObject()->isFunction());
        s.thisObject()->attachObject(jsFunc.toObject());
        s.thisObject()->attachObject(jsTarget.toObject());
        
        cobj->setCallback([jsFunc,jsTarget](int counter) {
            cout << "回调函数调用了： counter is " << endl;
            char* a = "sd";
            
            printf("counter is %d",counter);
            se::ScriptEngine::getInstance()->clearException();
            se::AutoHandleScope hs;
            
            se::ValueArray args;
            args.push_back(se::Value(counter));
            se::Object* target = jsTarget.isObject() ? jsTarget.toObject(): nullptr;
            
            jsFunc.toObject()->call(args,target);
        });
    }
    return true;
}
SE_BIND_FUNC(jsb_callback);

bool register_all_testio(se::Object* obj) {
    
    se::Value nsVal;
    if(!obj->getProperty("ns", &nsVal)) {
        // 不存在则创建一个js对象，相当于 let ns = {}
        se::HandleObject jsObj(se::Object::createPlainObject());
        // 给一个js对象设置一个全局对象
        nsVal.setObject(jsObj);
        
        // 将ns对象挂载到global对象上 名称为ns
        obj->setProperty("ns", nsVal);
    }
    se::Object* nsObj = nsVal.toObject();

    // 如果最后一个参数传入nullptr 则这个类在js中无法被new出来
    se::Class* cls = se::Class::create("TestJsb",nsObj,nullptr,_SE(jsb_constructor));

    cls->defineProperty("name",_SE(jsb_getName),_SE(jsb_setName));
    /** 设置jsObject 对象方法名称 */
    cls->defineFunction("test",_SE(jsb_Test));
    cls->defineFunction("console",_SE(jsb_Console));
    // 定义析构函数
    cls->defineFinalizeFunction(_SE(jsb_finalize));
    
    /** Install into jsvm*/
    cls->install();
    JSBClassType::registerClass<ns::TestJsb>(cls);

    __jsb_test_proto = cls->getProto();
    __jsb_test_class = cls;

    __jsb_test_proto->setProperty("id",se::Value("test1"));

    se::Value ctorVal;
    // 定义静态成员和静态函数
    if(nsObj->getProperty("TestJsb",&ctorVal) && ctorVal.isObject()) {
        cout << "构造函数存在" << endl;
        ctorVal.toObject()->setProperty("age", se::Value(22));
        ctorVal.toObject()->defineFunction("goHome", _SE(jsb_staticFunction));
    }
    

//    ctorVal.toObject();
//    cout << ctorVal.toObject()->getProperty("age",se::Value(22)) << endl;

    se::ScriptEngine::getInstance()->clearException();
    return true;
}

注意这些方法的操作对应的有个类支撑： TestJsb可以理解成mode,对应的是文件 test.hpp test.cpp

test.hpp:

#include <iostream>
#include <string>

using namespace std;

namespace ns {
    class TestJsb {
    private:
        std::string name;
        std::function<void(int)> _cb;

    public:
    void test();
    void console(const std::string& msg);
    void setName(const char* nameStr);
    string& getName();
    void setCallback(const std::function<void(int)>& cb);
    
    static void goHome() {
        cout << "静态函数goHome" << endl;
    }
    };
};

test.cpp:

#include "test.hpp"


void ns::TestJsb::setName(const char* nameStr) {
    cout << "setName 里面的名字 " << nameStr << endl;
    this->name = nameStr;

}

void ns::TestJsb::setCallback(const std::function<void (int)> &cb) {
    _cb = cb;
    if(cb !== nullptr) {
        cout << "设置了回调函数" << endl;
    } else {
        cout << "回调函数是空的" << endl;
    }
}

string& ns::TestJsb::getName() {
    return this->name;
}

void ns::TestJsb::test() {

}

void ns::TestJsb::console(const std::string& msg) {
    cout << "msg is " << msg << endl;
}

js层：

onLoad() {
    if (typeof jsb === 'undefined') return;

        if(typeof ns !== 'undefined' && ns.TestJsb) {
            const jsbTestObj = new ns.TestJsb();
            console.log('jsbTestObj is ',jsbTestObj);
            jsbTestObj.console("hello my baby");

            // jsbTestObj.name = "nb";
            console.log('name is ',jsbTestObj.name);

            jsbTestObj.name = "lck";
            console.log('After set name,name is ',jsbTestObj.name);
            console.log('age is ',jsbTestObj.age);
            console.log('id is ',jsbTestObj.id);

            // 静态函数调用
            if(ns.TestJsb.goHome) {
                ns.TestJsb.goHome();
            }
            if(ns.TestJsb.age) {
                console.log(ns.TestJsb.age);
            }

        } else {
            console.log('testJsb is not founded');
            console.log('ns is ',ns);
        }
}

?打包原生工程之后会发现cocos2d_libs.xcodeproj里面没有刚刚写好的c++文件，我的做法是复制进去

最后别忘记手动注册你写的模块,在jsb_module_register.cpp里面引入你自己的文件：比如：

#include "jsb_test.hpp"
#include<iostream>

#endif // (CC_TARGET_PLATFORM == CC_PLATFORM_IOS || CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID)

using namespace cocos2d;
using namespace std;

bool jsb_register_all_modules()
{
    se::ScriptEngine* se = se::ScriptEngine::getInstance();

    se->addBeforeInitHook([](){
        JSBClassType::init();
    });

    se->addBeforeCleanupHook([se](){
        se->garbageCollect();
        PoolManager::getInstance()->getCurrentPool()->clear();
        se->garbageCollect();
        PoolManager::getInstance()->getCurrentPool()->clear();
    });

    se->addRegisterCallback(jsb_register_global_variables);
    se->addRegisterCallback(JSB_register_opengl);
    se->addRegisterCallback(register_all_engine);
    se->addRegisterCallback(register_all_cocos2dx_manual);
    se->addRegisterCallback(register_platform_bindings);
    
    se->addRegisterCallback(register_all_network);
    se->addRegisterCallback(register_all_cocos2dx_network_manual);
    se->addRegisterCallback(register_all_xmlhttprequest);
    // extension depend on network
    se->addRegisterCallback(register_all_extension);
    cout << "注册自己的模块" << endl;
    se->addRegisterCallback(register_all_testio);
    

这就是jsb2.0手动绑定的全过程，是不是很简单?

?

总结下来就是js想调用c++层的方法，对应着c++层有对应的类对象方法和属性，只有这样js ,c++ 才能交互，内部原理就是c++层暴露出static方法给v8(js的底层实现)，这样js就可以调用这些接口从而实现交互