cef内核中js调用mfc代码

cef内核下，js调用mfc代码有很多种方式，本文只记录其中一种方式（重写CefV8Handler）。
第一步，创建类CSimpleV8Handler继承自CefV8Handler，并重写虚函数Execute，代码如下

#pragma once
#include "include/cef_v8.h"
class CSimpleV8Handler : public CefV8Handler
{
public:
	CSimpleV8Handler();
	~CSimpleV8Handler();
public:
	virtual bool Execute(const CefString& name, CefRefPtr<CefV8Value> object, const CefV8ValueList& arguments,
		CefRefPtr<CefV8Value>& retval, CefString& exception) OVERRIDE;
private:
	IMPLEMENT_REFCOUNTING(CSimpleV8Handler);
};

#include "stdafx.h"
#include "simple_v8handler.h"
#include "WebBrowse/elecmapvideo.h"

CSimpleV8Handler::CSimpleV8Handler(){}
CSimpleV8Handler::~CSimpleV8Handler(){}
bool CSimpleV8Handler::Execute(const CefString& name, CefRefPtr<CefV8Value> object, const CefV8ValueList& arguments,
	CefRefPtr<CefV8Value>& retval, CefString& exception)
{
	if (name == CefString("JSCallCpp")){		//JSCallCpp这个名字就是网页上回调的函数名字
		if (arguments.size() ==3 ){				//3表示网页上JSCallCpp函数的参数为3个
			CefString chnstr = arguments[1]->GetStringValue();
			//做自己的操作
			return true;
		}
	}
	return false;
}

第二步，修改simple_app.h文件，SimpleApp类继承自CefApp和CefRenderProcessHandler，完整代码如下

#ifndef CEF_TESTS_CEFSIMPLE_SIMPLE_APP_H_
#define CEF_TESTS_CEFSIMPLE_SIMPLE_APP_H_

#include "include/cef_app.h"
class SimpleApp : public CefApp, public CefRenderProcessHandler {
public:
	SimpleApp();
	virtual CefRefPtr<CefRenderProcessHandler> GetRenderProcessHandler() OVERRIDE{ return this; }
	virtual void OnContextCreated(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context) OVERRIDE;
	virtual void OnBeforeCommandLineProcessing(const CefString& process_type, CefRefPtr<CefCommandLine> command_line) {
		command_line->AppendSwitch("no-proxy-server");		//去掉代理-避免由于代理加载网页慢
	}
private:
	// Include the default reference counting implementation.
	IMPLEMENT_REFCOUNTING(SimpleApp);
};
#endif

对应的cpp文件实现代码如下

#include "simple_app.h"
#include "simple_handler.h"
#include "simple_v8handler.h"
#include "include/cef_browser.h"
#include "include/cef_command_line.h"
#include "include/wrapper/cef_helpers.h"

SimpleApp::SimpleApp(){}
void SimpleApp::OnContextCreated(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context)
{
	// The var type can accept all object or variable
	CefRefPtr<CefV8Value> pV8 = context->GetGlobal();
	// bind function 
	CefRefPtr<CSimpleV8Handler> pJsHandler(new CSimpleV8Handler());
	CefRefPtr<CefV8Value> pFunc = CefV8Value::CreateFunction(CefString("JSCallCpp"), pJsHandler);		//这里的JSCallCpp就是网页上的回调函数名字
	pV8->SetValue(CefString("JSCallCpp"), pFunc, V8_PROPERTY_ATTRIBUTE_NONE);
}

至此，在网页上js中调用JSCallCpp，就会在Execute中执行。