Looking for preferred way of widget interaction

[Blama]

Hi everyone,

I'm getting started with SmartGWT EE and I'm stuck now for quite a time on an app-design-widget-communication-problem and looking for a best practice advice.

System:
- SmartGWT EE 2.4 evaluation version
- Eclipse Indigo
- GWT 2.3
- SQL Server 2005, Windows 2008 Server
- sqljdbc_3.0.1301.101 from http://www.microsoft.com/downloads/de-de/details.aspx?familyid=a737000d-68d0-4531-b65d-da0f2a735707&displaylang=de
- Tomcat 7.0 (nothing deployed there yet, only hosted mode so far)
- FF 5.01

I build a nice app mockup so far with a navigation pane left and a main window with tabs right.
They are created from the onModuleLoad like this

public void onModuleLoad() {
    		Window.setMargin("0px");

		// main layout occupies the whole area
		mainLayout = new VLayout();
		mainLayout.setWidth100();
		mainLayout.setHeight100();

		navigationArea = new NavigationArea();
		navigationArea.setWidth("15%");
		
		
		mainArea = new MainArea();
		mainArea.setWidth("85%");

		navigationPlusMain = new HLayout();
		navigationPlusMain.setMembers(navigationArea, mainArea);

		mainLayout.addMember(navigationPlusMain);
		mainLayout.draw();
		// add the main layout container to GWT's root panel
		RootLayoutPanel.get().add(mainLayout);

The NavigationArea class looks like this:

public class NavigationArea extends HLayout {
	public StammdatenTreeGrid stammdatenTreeGrid;

	public void nothing() {
	};

	public NavigationArea() {
		super();

		this.setMembersMargin(20);
		this.setOverflow(Overflow.HIDDEN);
		this.setShowResizeBar(true);

		SectionStack sectionStack = new SectionStack();
		sectionStack.setVisibilityMode(VisibilityMode.MULTIPLE);
		sectionStack.setShowExpandControls(true);
		sectionStack.setAnimateSections(true);
		sectionStack.setVisibilityMode(VisibilityMode.MUTEX);
		sectionStack.setOverflow(Overflow.HIDDEN);

		SectionStackSection sectionStammdaten = new SectionStackSection(
				"Stammdaten");
		sectionStammdaten.setExpanded(true);

		stammdatenTreeGrid = new StammdatenTreeGrid();
		stammdatenTreeGrid.setHeight100();
		sectionStammdaten.addItem(stammdatenTreeGrid);

		SectionStackSection sectionAdmin = new SectionStackSection(
				"SmartGWT Admin");
		sectionAdmin.setExpanded(false);

		IButton adminButton = new IButton("Admin Console");
		adminButton.addClickHandler(new ClickHandler() {
			public void onClick(ClickEvent event) {
				com.smartgwtee.tools.client.SCEE.openDataSourceConsole();
			}
		});

		IButton generatorButton = new IButton("DS Generator");
		generatorButton.addClickHandler(new ClickHandler() {
			public void onClick(ClickEvent event) {
				com.smartgwtee.tools.client.SCEE.openDataSourceGenerator();
			}
		});

		sectionAdmin.addItem(adminButton);
		sectionAdmin.addItem(generatorButton);

		sectionStack.addSection(sectionStammdaten);
		sectionStack.addSection(sectionAdmin);

		this.addMember(sectionStack);
	}
}

Now from onModuleLoad() I can't access the public members of navigationArea. Eclipse does not offer them as auto-complete. I can't neither access the "StammdatenTreeGrid" member nor the "nothing" method.

My question is:
What is the best practice for communicating between widgets?
Is there a document on this? What am I doing wrong in my example?

Thanks a lot,
Blama

[Blama]

I think the problem is the same one as in this post: http://stackoverflow.com/questions/5...classsmart-gwt

It is also what is described (but not explained) in the tutorial http://www.javacodegeeks.com/2011/01...al-part-2.html as "Note that the navigation pane should be linked to the main area".

Best regards,
Blama

[Blama]

Error on my behalf.

I didn't show the members of buildinds class above "onModuleLoad".

The variable was typed like this:
public HLayout navigationArea;

Of course, this is wrong. Correct is
public NavigationArea navigationArea;

Eclipse didn't bother or warn because NavigationArea extends HLayout. But of course it didn't show the NavigationArea-specific methods.

Lesson learned (again): Always take breaks while programming.