Thank you for your reply.
I did know that I had to add the element before calling those methods,
but sure enough I had forgotten that the panel in line 4 hadn't been
added yet, as it was part of a cascade of constructors. Your reply
helped me point that one out.
Thanks,
G.
On Jul 1, 10:55 am, Daniel Simons <daniel.simo...@gmail.com> wrote:
> i) The problem here is that you are trying to reference an element that has
> not yet been added to the dom.
>
> Check where you are adding the element...most likely a you have a call to
> RootPanel.get().add(elem). Be sure that this happens before calling
> getElementsById().
>
> ii) I prefer to create my own Generic Widgets by extending ComplexPanel.
> This is helpful because you can pass in any tag name that you'd like:
>
> public class ContainerTag extends ComplexPanel{
> public ContainerTag(String tagName) {
> setElement(DOM.createElement(tagName));
> }
>
> }
>
> Then you can use: ContainerTag div = new ContainerTag("div");
>
> Daniel
>
> On Thu, Jul 1, 2010 at 12:13 PM, giacomo <gia.ghid...@gmail.com> wrote:
> > Hi everyone!
>
> > SUMMARY
> > =========
>
> > I'm facing a problem with Document.get().getElementById(String) (in
> > Java) and $doc.getElementById(String) (in JavaScript) returning nulls.
>
> > My design goal is to define a <div> element in the Java code and add
> > it to the document, so that I can then retrieve it in the JSNI method
> > and use JavaScript libraries to draw stuff within it.
>
> > DESCRIPTION
> > ============
>
> > To make problem description simpler, here is my GWT code:
>
> > 1 protected void draw() {
> > 2 String id = "divId";
> > 3 HTML divElement = new HTML("<div id=\'" + id + "\'>Hello
> > World</
> > div>");
> > 4 getChartPanel().add(divElement); //getChartPanel() returns
> > a Panel
> > 5 Window.alert("The element ID is " + id);
> > 6 Element element = Document.get().getElementById(id);
> > 7 Window.alert("The GWT element ID is " + element.getId());
> > 8 drawJS(id);
> > 9 }
> > 10
> > 11 public static native void drawJS(String divID) /*-{
> > 12 $wnd.alert("The JS element ID is " + divID);
> > 13 var chartPanel1 = $doc.getElementById(divID);
> > 14 $wnd.alert("The chart panel is " + chartPanel1);
> > 15 var chartPanel2 = document.getElementById(divID);
> > 16 $wnd.alert("The chart panel is " + chartPanel2);
> > 17 chartPanel.innerHTML("Hello, World!");
> > 18 }-*/;
>
> > When the draw() method is called I get the following:
>
> > i) Window on line 5 pops up with "The element ID is divId";
> > ii) Window on line 7 pops up with "The GWT element ID is null";
> > iii) Window on line 12 pops up with "The JS element ID is divId";
> > iv) Window on line 14 pops up with "The chart panel is null";
> > v) Window on line 16 pops up with "The chart panel is null"; and
> > vi) A JavaScriptException is raised in development mode at line 17:
>
> > -----------------------------------------------------------
> > 09:50:16.235 [ERROR] [sensor_network] Uncaught exception escaped
> > com.google.gwt.core.client.JavaScriptException: (ReferenceError):
> > chartPanel is not defined
> > fileName:http://127.0.0.1:8888
> > lineNumber: 7
> > stack: ("divId")@http://127.0.0.1:8888:7
> > @:0
> > -----------------------------------------------------------
>
> > ANALYSIS
> > ========
>
> > I inspected the Web page with FireBug and the <div> element with id =
> > "divId" DOES exist after it is added in the Java code. However,
> > neither the Java nor the JavaScript methods are able to retrieve it.
>
> > QUESTIONS
> > ==========
>
> > i) What am I doing wrong and how do I fix it?
>
> > ii) Is there a better way to add a <div> element in Java and pass it
> > to a JavaScript method, so that the latter can use it to add stuff
> > (e.g., JavaScript-based charts) in it?
>
> > Thank you.
>
> > G.
>
> > --
> > You received this message because you are subscribed to the Google Groups
> > "Google Web Toolkit" group.
> > To post to this group, send email to google-web-tool...@googlegroups.com.
> > To unsubscribe from this group, send email to
> > google-web-toolkit+unsubscr...@googlegroups.com<google-web-toolkit%2bunsubscr...@googlegroups.com>
> > .
> > For more options, visit this group at
> >http://groups.google.com/group/google-web-toolkit?hl=en.
--
You received this message because you are subscribed to the Google Groups
"Google Web Toolkit" group.
To post to this group, send email to google-web-tool...@googlegroups.com.
To unsubscribe from this group, send email to
google-web-toolkit+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/google-web-toolkit?hl=en.
