如何在QWebView中获取Javascript以创建基于C ++的类的新实例？ [英] How to get Javascript in a QWebView to create new instances of C++ based classes?

问题描述

我使用 addToJavaScriptWindowObject

I've successfully added an C++ object to a QWebFrame with addToJavaScriptWindowObject, and can call a slot on that object from javascript.

但我真正想做的是让其中一个插槽返回一个新对象。例如，我有一个这样的插槽，它返回一个QObject派生类实例：

But what I really want to do is have one of those slots return a new object. For example, I have a slot like this, which returns a QObject derived class instance:

   MyObject* MyApp::helloWorld()
   {
          //MyObject is dervied from QObject
          return new MyObject();
   }

我可以像这样成功地从javascript调用这个插槽

I can call this slot from javascript successfully like this

   var foo=myapp.helloWorld();

但是foo似乎是空的，我无法拨打任何插槽或访问任何
来自Javascript的属性。

But foo appears to be empty, I can't call any slots or access any properties on it from Javascript.

关于如何实现这一点的任何想法？

Any ideas on how I can achieve this?

推荐答案

我考虑过的一个相当丑陋的黑客是使用addToJavaScriptWindowObject来删除我想要以随机名称返回到窗口对象的对象，然后让我的插槽返回对象实例的名称：

One rather ugly hack I've considered is to use addToJavaScriptWindowObject to drop the object I want to return into the window object with a random name, then have my slot return the name of the object instance instead:

QString MyApp::helloWorld()
{
     //general a unique name for the js variable
     QString name=getRandomVariableName();

     //here's the object we want to expose to js
     MyObject* pReturn=new MyObject();

     //we make attach our object to the js window object    
     getWebFrame()->addToJavaScriptWindowObject(name, pReturn,
         QScriptEngine::ScriptOwnership);  

     //tell js the name we used
     return name;
}

可以编写JS以检查返回值是否为字符串，并且如果是，从窗口抓取对象。：

The JS can be written to check if the return value is a string, and if it is, grab the object from the window.:

var foo=myapp.helloWorld();
if (typeof foo == "string")
{
    foo=window[foo];
}

有点难看，但会让我走过，直到有更好的方法出现。未来的Qt版本将统一脚本支持，所以它都基于WebKit中的JavaScriptCore，所以希望这会有所改进！

A little ugly, but will get me by until a better method comes along. Future Qt versions are going unify the scripting support so that it's all based on the JavaScriptCore in WebKit, so hopefully this will improve then!

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