$ wnd.google.visualization未定义 [英] $wnd.google.visualization is undefined

问题描述

我目前正在构建一个基于SmartGWT的Web应用程序（使用Portlet布局）。所以我有几个Portlet，它基本上扩展了GWT窗口的不同内容。现在我想让Portlet显示 Dygraphs 。所以我创建了一个RPC Service实现，它返回一个JSON字符串（基于DataTable对象）。

因为我不能直接序列化一个DataTable对象，所以我使用

 字符串json = JsonRenderer.renderDataTable（data，true，true）.toString（）; 
  

其中data是DataTable类型的。

现在这个String被正确地传递到我想创建Dygraph的客户端。在这个线程中，有人建议使用

  public static native DataTable toDataTable（String json）
 /  -  {return new $ wnd.google.visualization.DataTable（eval（（+ json +） ）））; }  -  /; 
  

如果我在我的GWT客户端代码中使用了这个，我收到一个错误消息：

  com.google.gwt.core.client.JavaScriptException：（TypeError）：$ wnd.google.visualization未定义
  

我错过了一些可视化API的导入吗？我在哪里必须实例化它？

或者有另一种方法可以将JSON数据字符串导入Dygraph中？我找不到任何示例...

感谢您的任何提示！

解决方案

我假设你已经在你的模块的XML中包含了visualization.jar和visualization命名空间。

 < inherits NAME = com.google.gwt.visualization.Visualization/> 
  

这会给你类。你可能已经这样做了，否则你会得到一个编译器错误。 然而，你也必须包含来自谷歌服务器的实际可视化JavaScript文件（可视化文件.jar只是一个包装）。这可以通过两种不同的方式完成：

1。）将其包含在主页中：

 < script type =text / javascript> 
 google.load（visualization，1，{'packages'：[corechart]}）; 
< / script> 
  

或

2。）加载它动态地在你需要它的地方：

  VisualizationUtils.loadVisualizationApi（onLoadCallback，MotionChart.PACKAGE）; 
  

请参阅 http://code.google.com/docreader/#p=gwt-google-apis&s=gwt- google-apis& t = VisualizationGettingStarted

顺便说一句。我分叉了Dygraphs项目并将GWT包装器更改为更像其他可视化包装器。你可以在这里查看： https://github.com/timeu/dygraphs

编辑：我使用GWT 2.8的新JsInterop为dygraph创建了一个新的GWT包装器： https://github.com/timeu/dygraphs-gwt

注意：我改变了dygraph中的一些行为，并添加了一些上游代码中不可用的功能。

I'm currently building a SmartGWT-based web application (using the Portlet Layout). So I have several "Portlet", which basically extend GWT Window with different content. Now I want a Portlet to display Dygraphs. So I've created an RPC Service implementation which returns a JSON String (based on a DataTable object).

Since I cannot directly serialize a DataTable object I use

String json = JsonRenderer.renderDataTable(data, true, true).toString();

where "data" is of type DataTable.

Now this String gets correctly passed to the client side where I want to create the Dygraph. In this thread , someone suggested to use

public static native DataTable toDataTable(String json) 
/-{ return new $wnd.google.visualization.DataTable(eval("(" + json + ")")); }-/;

If I use this in my GWT client code, i get an error saying

com.google.gwt.core.client.JavaScriptException: (TypeError): $wnd.google.visualization is undefined

Do i miss some "import" of the visualization API? Where do i have to instantiate it?

Or is there another way to get the JSON datastring into the Dygraph? I can't find any examples...

Thank you for any hint!

解决方案

I assume you have included the visualization.jar and the visualization namespace in your module's XML

<inherits name="com.google.gwt.visualization.Visualization"/>

This will give you the Classes. You probably have done this otherwise you would have gotten a compiler error.

However you also have to include the actual visualization javascript file from the google servers (the visualization.jar is only a wrapper). This can be done in two different ways:

1.) Include it in the host page:

<script type="text/javascript">
        google.load("visualization", "1", {'packages' : ["corechart"] });
</script>

or

2.) Load it dynamically where you need it:

VisualizationUtils.loadVisualizationApi(onLoadCallback, MotionChart.PACKAGE);

see http://code.google.com/docreader/#p=gwt-google-apis&s=gwt-google-apis&t=VisualizationGettingStarted

Btw. I have forked the Dygraphs Project and changed the GWT wrapper to more like the other visualization wrappers. You can check it out here: https://github.com/timeu/dygraphs

Edit: I have a new GWT wrapper for dygraphs that uses the GWT 2.8's new JsInterop: https://github.com/timeu/dygraphs-gwt

Note: I changed some behaviour in dygraphs and added some features which weren't available in the upstream code.

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