JSNI troubles (TypeError)

[dhoffer]

I'm trying to write a little JNSI but am having trouble, I get an
exception with this this message (TypeError): Object expected

When I run this code:

public static native void init(String id) /*-{

var elem = $doc.getElementById(id);
addEvent(elem, 'drop', droppedHandler);
addEvent(elem, 'dragover', allowDrop);

function allowDrop(event) {
if (event.stopPropagation)event.stopPropagation();
if (event.preventDefault)event.preventDefault();
return false;
}

function droppedHandler(event) {
if (event.preventDefault)event.preventDefault();
return false;
}

var addEvent = (function () {
if (document.addEventListener) {
return function (el, type, fn) {
if (el && el.nodeName || el === window) {
el.addEventListener(type, fn, false);
} else if (el && el.length) {
for (var i = 0; i < el.length; i++) {
addEvent(el[i], type, fn);
}
}
};
} else {
return function (el, type, fn) {
if (el && el.nodeName || el === window) {
el.attachEvent('on' + type, function () {
return fn.call(el, window.event);
});
} else if (el && el.length) {
for (var i = 0; i < el.length; i++) {
addEvent(el[i], type, fn);
}
}
};
}
})();
}-*/;

Where in my extended RichTextArea I set a unique ID on its element
via:

private final String id = UUID.uuid();
getElement().setId(id);

I don't think the problem is in the body of the method...i think there
is something wrong with getting a valid Element to the addEvent()
method. Also is there a way to debug this somehow so I can see what
is really happening?

Thanks,
-Dave

[Joseph Lust]

Generally it is an antipattern to reference by id in GWT due to how UiBinder works behind the scenes with Id's. Can you pass an element into the JSNI method on which to operate?

Sincerely,

Joseph

[dhoffer]

I tried that too and got the same error.

I was given the javascript code that started like this (where dropBox
was the id of the div)

var dropBox = document.getElementById("dropBox");
addEvent(dropBox, 'drop', droppedHandler);
addEvent(dropBox, 'dragover', allowDrop);

And I was asked to add this to our GWT app where the widget is now a
RichTextArea. Initially I used getElement() and passed that directly
into the init method so the JSNI method used the passed elem
directly...but that gave the same exception. I just don't understand
why.

Thanks,
-Dave

[Alfredo Quiroga-Villamil]

Decorate your JSNI with some "console.log(...." statements. Open up in
your browser your Dev Tools (depends on the browser you are using),
look at the console and narrow down the issue there.

If you provide a simple concise example that allows the issue to be
easily duplicated, I'll be happy to take a look at it here as well.

Best regards,

Alfredo

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AOL/Yahoo/Gmail/MSN IM: lawwton

[Thomas Broyer]

How about converting the code to Java/GWT?

widget.addDomHandler(new DropHandler() {

    @Override

    public void onDrop(DropEvent event) {

        event.stopPropagation();

        event.preventDefault();

    }

}, DropEvent.getType());

widget.addDomHandler(new DragOverHandler() {

    @Override

    public void onDragOver(DragOverEvent event) {

       event.preventDefault();

    }

}, DragOverEvent.getType());

[dhoffer]

Thanks for the replies.  With the console logging I was able to figure out why it was failing, it's working now.

But I also like the idea to converting to Java/GWT...I'll try that too.

Thanks!

-Dave