On Feb 14, 11:19 pm, Jim Douglas <[email protected]> wrote:
> I've been playing with some code to register oncut against a GWT
> TextBox. The basic event registration seems to be working ok; I get
> to the event handler function, and the "return false" part seems to be
> working as designed (the cut is blocked). The problem is that I'm
> trying to call back from the event handler into a Java method ... but
> it's never getting there. Am I doing something obviously stupid
> here? The syntax looks right, and I'm not getting any errors. But
> when I run this, I get the two alerts bracketing the attempt to call
> from JavaScript to Java, but that method isn't getting invoked.
that's a "scope" issue (very common in JavaScript).
> Here's my test code. I added this to the end of StockWatcher
> onModuleLoad():
>
> registerOnCut(nameField.getElement());
>
> And added these functions:
>
> public native void registerOnCut(Element element)
> /*-{
> element.oncut = function()
> {
> $wnd.alert("about to invoke Java doCut");
>
> $entry([email protected]::doCut());
The "this" is no longer your class here, as the function is a
callback. First assign it to a variable outside the function and then
pass a function to $entry(), not a reference to the method.
Which leads to:
public native void registerOnCut(Element element) /*-{
var that = this;
element.oncut = function() {
$wnd.alert("about to invoke Java doCut");
$entry(function() {
[email protected]::doCut()
();
});
$wnd.alert("returned from Java doCut");
return false;
};
}-*/;
(or you could wrap the whole 'oncut' callback in $entry).
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