GWT: add handler to native js event onafterprint

Question

I have a GWT widget representing a document print preview. In this widget the print button/action is managed by an external Chrome service. I need to detect the native window.onafterprint event from my jave code.

How can I do that?

Providing code with no success:

var popup = $wnd.open(url, title, ""); // this open the preview window

popup.onafterprint = function (ev) {
   $wnd.console.log("mess 2"); // to try to see if detect the print button
}

Answer 1

One way to achieve this is to export a Java handler to Javascript, this way the Javascript event can call the Java handler:

public MyUtilityClass {
    public static int handleOnAfterPrint(String message) { ... }
    public static native void exportStaticMethod() /*-{
       $wnd.handleOnAfterPrint =
          $entry(@mypackage.MyUtilityClass::handleOnAfterPrint(Ljava/lang/String;));
    }-*/;
}

So you can do:

popup.onafterprint = function (ev) {
  handleOnAfterPrint("mess 2"); 
}