Re: Is it possible to find widget on DOM and call it's jsobject java nonstatic method

Yes, you can do it very easy using two nice libraries I contribute with: gwtquery and gwtexporter

1.- Use gquery to find widgets in the DOM using css selectors

2.- Use gwtexporter to expose widget methods and and gquery finders

I've committed a maven project [1] to the gwtexporter repository with a very simple example so as you can use it as reference (I have used the gquery archetype btw) .

As you can see in the complete code [2] I use a class to export some static methods, which will be exposed to javascript using gwtexporter generator:

  @ExportPackage("")

  @Export("js")

  public static class Exposer implements Exportable {

    public static Widget[] getWidgets(String selector) {

      return $(selector).widgets().toArray(new Widget[0]);

    }

  }

Then it is necessary to expose the methods you want from your widgets, I use the ExportOverlay feature in gwtexporter so as I do not modify the original widget (gwt Button in this case)

  @ExportPackage("js")

  @Export

  public static interface ButtonOverLay extends ExportOverlay<Button> {

    void setText(String s);

    void click();

  }

Finally you can use js in this way to find widgets and call theirs methods

<script>

  var widget = js.getWidgets(".gwt-Button");

  var button = new js.Button(widget);

  button.click();

</script>

[1] svn checkout http://gwt-exporter.googlecode.com/svn/examples/export-widgets

[2] http://code.google.com/p/gwt-exporter/source/browse/examples/export-widgets/src/main/java/org/gquery/ewidget/client/ExportWidget.java

- Manolo

On Fri, May 4, 2012 at 2:15 PM, Alexander Kozyncev <kozyncev@gmail.com> wrote:

General Aim:  find widget's javascript object and call it's exported
java method

Tried: gwt-2.4.0 (with and without gwt-exporter 2.3.0)

Description:
To find gwt's widget on DOM in Java Applet code and call it's java
method(non static)
<pre><code>
JSObject win = JSObject.getWindow(this);
JSObject doc = (JSObject) win.getMember("document");
JSObject gwtWidget = (JSObject) doc.call("getElementsByName",
widgetName);

//todo: have possibility to call `exported` java method over here,
smth like:
//Object[] params = new Object[1];
//params[0] = widgetName;
//Object result = gwtWidget.call("exportedJavaMethod", params);

//todo: or just call global ($wnd) static JSNI bridge method:
//Object result = win.call("exportedJavaMethod", params);
//
</code></pre>

The problem is: I can find by widget's id not the widget, but it's
DivElement which does not have any exported instanced methods.

My widget class is Exportable (gwt-export):
<pre><code>
@Export(value="somewidget")
public class SomeWidget extends SimplePanel implements ..., Exportable
{
    private final String id = "id_some_widget_" + count++;
    private static int count = 0;

    public SomeWidget () {
        getElement().setAttribute("name", id);
        getElement().setId(id);
    }
    ...

    public static Element getInstanceById(String elementId) {
        Element someWidget= DOM.getElementById(elementId);
        return someWidget;
    }

    public String getSomeInstancedData() {
        return "useful_inner_data" + this.id;
    }
</code></pre>

So, for example I'd like to find the concrete widget added to DOM and
call nonstatic method `getSomeInstancedData()` in javascript. Is it
possible at all?

Suppose smth like:
<pre><code>
var someWidget = document.getElementById(widgetId);
alert(someWidget.getSomeInstancedData());

//or:
var someWidgetExported =
com.mypackage.widgets.somewidget.getInstanceById(listenerId);
alert(someWidgetExported.getSomeInstancedData());
</code></pre>

In Base module I write:
<pre><code>
ExporterUtil.exportAll();
</code></pre>

There is a View(ViewWithSomeWidget.ui.xml) that contains this widget:
<pre>
...
base:Form
base:SomeWidget ui:field="someWidget" ...
...
/base:SomeWidget
...
</pre>

When SomeWidget does not implement Exportable, project runs well, but
I couldn't call nonstatic methods of found widget's DIV element.

By the time, to solve the problem SomeWidget implements Exportable,
but progect doesn't show View with the SomeWidget well because of
ClassCastException using deferred binding:
<pre><code>
ClassCastException: com.mypackage.widgets.SomeWidgetExporterImpl
cannot be cast to com.mypackage.widgets.SomeWidget
</code></pre>

So, probably there are any other methods to find widget's javascript
object and call it's exported java method? In any ways, any idea is
much appreciated.

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