Hi,
i am trying to write a vaadin Application. But i am stucked with the first Problem.
I want to have a Navigation and a Content Area on my Application.
If i click something on the Navigation, only the Contentarea should change => Sounds genius 
Therefore i read the wiki and found this:
https://vaadin.com/book/vaadin7/-/page/advanced.navigator.html
I modified the code and got a really strange behavior, that i dont undestand. I added a Button, whats adds a new Button to the Navigation. (I only did this, to verify, that only the content area reloads by clicking on the navigation buttons).
But: When i go on the Page the First time, and i click the test button, then a new test button appears. If i now click on View1, the button disapears.
Until this moment, i pressed one of the Buttons View1 or View2 and i add now a test Button via the Button “test”, and i click again an View1 oder View2 the button dont disapear.
I hope i described my problem well enough for understanding.
Here is my code:
public class MainView extends VerticalLayout implements View {
public static final String NAME = "";
private Panel panel;
// Menu navigation button listener
class ButtonListener implements Button.ClickListener {
String menuitem;
public ButtonListener(String menuitem) {
this.menuitem = menuitem;
}
@Override
public void buttonClick(ClickEvent event) {
// Navigate to a specific state
getUI().getNavigator().navigateTo("main" + "/" + menuitem);
}
}
public MainView() {
setSizeFull();
// Layout with menu on left and view area on right
HorizontalLayout hLayout = new HorizontalLayout();
hLayout.setSizeFull();
// Panel for the navgigation
Panel menu = new Panel("Navigation");
menu.setHeight("100%");
menu.setWidth(null);
//creating the navigationcontent
final VerticalLayout menuContent = new VerticalLayout();
menuContent.addComponent(new Button("View1",
new ButtonListener("View1")));
menuContent.addComponent(new Button("View2",
new ButtonListener("View2")));
menuContent.setWidth(null);
menuContent.setMargin(true);
menu.setContent(menuContent);
//Panel dem Layout hinzufĂĽgen
hLayout.addComponent(menu);
// A panel that contains a content area on right
panel = new Panel("Inhalt");
panel.setSizeFull();
hLayout.addComponent(panel);
hLayout.setExpandRatio(panel, 1.0f);
addComponent(hLayout);
setExpandRatio(hLayout, 1.0f);
[b]
//create new test navigation button
Button test = new Button("test", new Button.ClickListener() {
@Override
public void buttonClick(ClickEvent event) {
menuContent.addComponent(new Button("test"));
}
});
menuContent.addComponent(test);
[/b]
}
@Override
public void enter(ViewChangeEvent event) {
VerticalLayout panelContent = new VerticalLayout();
panelContent.setSizeFull();
panelContent.setMargin(true);
panel.setContent(panelContent); // Also clears
//Standardcontent anzeigen
if (event.getParameters() == null
|| event.getParameters().isEmpty()) {
panelContent.addComponent( new Label("DefaultPage"));
return;
}
// Display the fragment parameters
Label watching = new Label(
"You are currently watching a " + event.getParameters());
watching.setSizeUndefined();
panelContent.addComponent(watching);
panelContent.setComponentAlignment(watching,
Alignment.MIDDLE_CENTER);
}
}The question is why this is happening and the next question is should i do my navigation like this.
I am reading about use a differnt View for each page, but in my understanding, if i am doing this, this way. I only have one View which loads different CustomComponents to my ContentArea.
Thanx for Helping