Question

I have a GWT application that features two frames (com.google.gwt.user.client.ui.Frame). Via Frame.setUrl(…) I can load arbitrary web pages without any problems. Of course, user then can click on links on the loaded pages, which in turn load the corresponding pages? How can I keep track of the currently loaded pages in both frames?

Below are my current attempt using two types of listeners; I found the code snippets on the Web. Both events fire, but still I don’t know how to get the current loaded URL

import com.google.gwt.event.dom.client.LoadEvent;
import com.google.gwt.event.dom.client.LoadHandler;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.EventListener;
import com.google.gwt.user.client.ui.Frame;

public class BrowserTabFrame extends Frame implements EventListener {

 public BrowserTabFrame() {
    super();
    sinkEvents(Event.ONLOAD);

    addLoadHandler(new LoadHandler() {      
        @Override
        public void onLoad(LoadEvent event) {
            System.out.println(event.getSource());
            // <iframe style="visibility: visible;" id="ext-gen17" src="http://..." class="gwt-Frame"></iframe>
            // however, the src attribute never changes
        }
    });
  }

  @Override
  public void onBrowserEvent(Event event) {
    super.onBrowserEvent(event);
    if (DOM.eventGetType(event) == Event.ONLOAD) 
        System.out.println(event.getCurrentEventTarget());
        // [object HTMLIFrameElement]
        // no idea what to do with it   
  }
}

Thanks for any hints!

Christian

Answer 1

The src attribute of an iframe will never change but the URL property of the contained document will. You can get this value using JSNI:

private native String getIframeUrl(IFrameElement frame) /*-{
  if (frame.contentDocument !== undefined) {
    return frame.contentDocument.URL;
  } else if (frame.contentWindow !== undefined &&
             frame.contentWindow.document !== undefined)
  {
    return frame.contentWindow.document;
  } else {
    return null;
  }
}-*/;

...

Window.alert(getIframeUrl(myFrame.getElement()));

However note that, if the security context (any of protocol, domain or port number) of the iframe changes, the browser will not allow the containing application to access the document in the frame.