How to use

addBeforeSelectionHandler

method

in

com.google.gwt.user.client.ui.TabPanel

public static void add(TabPanel source, TabListener listener) {
 WrappedTabListener t = new WrappedTabListener(listener);
 source.addBeforeSelectionHandler(t);
 source.addSelectionHandler(t);
}

public static void add(TabPanel source, TabListener listener) {
 WrappedTabListener t = new WrappedTabListener(listener);
 source.addBeforeSelectionHandler(t);
 source.addSelectionHandler(t);
}

public static void add(TabPanel source, TabListener listener) {
 WrappedTabListener t = new WrappedTabListener(listener);
 source.addBeforeSelectionHandler(t);
 source.addSelectionHandler(t);
}

/**
 * @return this editor as a Widget.
 */
public Widget asWidget() {
  VerticalPanel panel = new VerticalPanel();
  panel.add(new ContentGroupLabel(Singleton.MESSAGES.label_serviceDetails()));
  panel.add(new ContentDescription(Singleton.MESSAGES.description_serviceDetails()));
  panel.add(createImplementationDetailsPanel());
  TabPanel tabs = new TabPanel();
  tabs.setStyleName("default-tabpanel"); //$NON-NLS-1$
  tabs.getElement().setAttribute("style", "margin-top:15px;"); //$NON-NLS-1$ //$NON-NLS-2$
  tabs.add(createGatewayDetailsPanel(), Singleton.MESSAGES.label_gateways());
  tabs.add(createThrottlingDetailsPanel(), Singleton.MESSAGES.label_throttling());
  tabs.addBeforeSelectionHandler(new BeforeSelectionHandler<Integer>() {
    @Override
    public void onBeforeSelection(BeforeSelectionEvent<Integer> event) {
      _toolstrip.doCancel();
    }
  });
  panel.add(tabs);
  tabs.selectTab(0);
  return panel;
}