cef -- JS与C++互调

JS调用C++函数

• （1）继承CefRenderProcessHandler
• （2）重写OnContextCreated虚函数
• （3）绑定值或者JS对象（数组）到window对象上
• （4）在js中访问window对象上绑定的值（或者JS对象、数组等）

// Called immediately after the V8 context for a frame has been created. To
  // retrieve the JavaScript 'window' object use the CefV8Context::GetGlobal()
  // method. V8 handles can only be accessed from the thread on which they are
  // created. A task runner for posting tasks on the associated thread can be
  // retrieved via the CefV8Context::GetTaskRunner() method.
  ///
  /*--cef()--*/
  virtual void OnContextCreated(CefRefPtr<CefBrowser> browser,
                                CefRefPtr<CefFrame> frame,

OnContextCreated接口实在chrome的V8引擎创建后调用的，在这里我们需要将JS里面调用的函数和C++的执行函数关联起来，这样JS就可以“执行”C++代码了。

我们的函数都是定义在window对象中的，根据注释我们需要GetGlobal获取这个对象。

void SimpleApp::OnContextCreated(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context)
{
    // The var type can accept all object or variable
    CefRefPtr<CefV8Value> window = context->GetGlobal();

    // bind value into window[or you can bind value into window sub node]
    CefRefPtr<CefV8Value> strValue = CefV8Value::CreateString("say yes");
    window->SetValue("say_yes", strValue, V8_PROPERTY_ATTRIBUTE_NONE);
}

CefRefPtr<CefV8Handler> myV8handle = new CCefV8Handler();
        CefRefPtr<CefV8Value> myFun = CefV8Value::CreateFunction(L"SetAppState", myV8handle);
        static_cast<CCefV8Handler*>(myV8handle.get())->AddFun(L"SetAppState", &CChromeJsCallback::JsSetAppState);
        pObjApp->SetValue(L"SetAppState", myFun, V8_PROPERTY_ATTRIBUTE_NONE);