Javascript本机方法引发意外异常 [英] Javascript native method throws unexpectedly exception

问题描述

我正在将vaadin项目从 vaadin 6 版本更新为 vaadin 7 。它包含一些在旧版本中很好的原生Javascript方法。但是有些人在被调用时会抛出异常。我不熟悉 Javascript 编程，因此我无法识别错误的来源。特别的方法是：

I am updating a vaadin project from vaadin 6 version to vaadin 7. It contains some native Javascript methods which work well in the old version. However some of them throw an exception when they should be called. I am not acquainted enough to Javascript programming and therefore I am not able to identify the source of the error. In particular the method is:

 protected static native void addSthToImg()
    /*-{
        $wnd.$(document).ready(function() {
            var = $wnd.$;
            var('.settingswrapper > img').addClass("imgStartup");
            if (var('.settingswrapper > img').hasClass("imgStartup")) {
                console.log("imgStartup exist");
                var('.settingswrapper > img')
      .animate(null, 300, function() {
                    var('.settingswrapper > img').removeClass("imgStartup");
                    var('.settingswrapper > img').addClass("imagePopIn");

                });
            }
        });
    }-*/;

在Chrome的控制台中，我看到错误堆栈跟踪：

On the Console in Chrome I see the error stack trace:

Caused by: com.google.gwt.core.client.JavaScriptException: (TypeError) : Object [object global] has no method '$'

什么可能是错误的可能原因，为什么它在旧版本中工作？一个jar /库缺少？

What could be a possible cause of the error and why is it working in the old version? Is a jar/library missing?

推荐答案

看起来像jQuery别名 $ 没有在全局范围中定义（由 $ wnd 表示）。你确定你的页面包含jQuery？

Seems like jQuery alias $ is not defined in the global scope (denoted by $wnd). Are you sure your page includes jQuery?

你应该有一些类似< script src =/ js / jquery.jstype =文本/ javascript>< / script> （但指向项目中jquery.js的实际位置）。我不知道Vaadin是否自动管理JavaScript库，因为我不熟悉框架。

You should have something like <script src="/js/jquery.js" type="text/javascript"></script> (but pointing to the actual location of jquery.js in your project) in your HTML source. I don't know if Vaadin manages JavaScript libraries automatically, since I'm not familiar with the framework.

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