Как изменить основной вид приложения Vaadin 7?

Question

Я хочу написать приложение Vaadin 7 (см. MyVaadinUI ниже), в котором предлагается ввести имя пользователя и пароль.

Если они верны, то должен появиться другой вид (см. MainUI) и взять всю область (заменить вид входа).

Я пытался осуществить этот переход в методе MyVaadinUI.goToMainWindow, но я получаю ошибку

java.lang.RuntimeException: Component must be attached to a session when getConnectorId() is called for the first time 
    at com.vaadin.server.AbstractClientConnector.getConnectorId(AbstractClientConnector.java:417) 
    at com.vaadin.server.communication.ConnectorHierarchyWriter.write(ConnectorHierarchyWriter.java:67) 
    at com.vaadin.server.communication.UidlWriter.write(UidlWriter.java:143) 
    at com.vaadin.server.communication.UidlRequestHandler.writeUidl(UidlRequestHandler.java:149) 
    at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:97) 
    at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:37) 
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1371) 
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:238) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:848) 

при запуске приложения и нажмите на кнопку.

Как это исправить?

@Theme("mytheme") 
@SuppressWarnings("serial") 
public class MyVaadinUI extends UI 
{ 
    private TextField userNameTextField; 
    private PasswordField passwordTextField; 

    @WebServlet(value = "/*", asyncSupported = true) 
    @VaadinServletConfiguration(productionMode = false, ui = MyVaadinUI.class, widgetset = "ru.mycompany.vaadin.demo.AppWidgetSet") 
    public static class Servlet extends VaadinServlet { 
    } 

    @Override 
    protected void init(VaadinRequest request) { 
     final VerticalLayout layout = new VerticalLayout(); 
     layout.setMargin(true); 
     setContent(layout); 

     addUserNameTextField(layout); 
     addPasswordTextField(layout); 

     addButton(layout, request); 
    } 

    private void addPasswordTextField(Layout aLayout) { 
     passwordTextField = new PasswordField("Пароль:"); 

     aLayout.addComponent(passwordTextField); 

    } 

    private void addUserNameTextField(final Layout aLayout) { 
     userNameTextField = new TextField("Пользователь:"); 

     aLayout.addComponent(userNameTextField); 
    } 


    private void addButton(final Layout aParent, final VaadinRequest request) { 
     final Button button = new Button("Войти"); 
     button.addClickListener(new Button.ClickListener() { 
      public void buttonClick(Button.ClickEvent event) { 
       final boolean credentialsCorrect = checkCredentials(); 

       if (credentialsCorrect) { 
        goToMainWindow(request); 
       } else { 
        [...] 
       } 
      } 
     }); 
     aParent.addComponent(button); 
    } 

    private void goToMainWindow(final VaadinRequest aRequest) { 

     final MainUI mainUI = new MainUI(); 
     mainUI.init(aRequest); 
     setContent(mainUI); 
    } 

} 

@Theme("mytheme") 
@SuppressWarnings("serial") 
public class MainUI extends UI { 
    @Override 
    protected void init(final VaadinRequest vaadinRequest) { 
     final HorizontalSplitPanel splitPanel = new HorizontalSplitPanel(); 

     setContent(splitPanel); 

     splitPanel.setSizeFull(); 
     splitPanel.setSplitPosition(200, Unit.PIXELS); 

     final String[] tabLabels = new String[] { 
       "Tree item 1", 
       "Tree item 2"}; 

     final Tree tree = new Tree(); 

     for (int i=0; i < tabLabels.length; i++) 
     { 
      addTreeItem(tree, tabLabels[i]); 
     } 

     splitPanel.setFirstComponent(tree); 
     splitPanel.setSecondComponent(new Label("Test")); 
    } 

    private void addTreeItem(final Tree aTree, final String aLabel) { 
     aTree.addItem(aLabel); 
    } 
} 

Answer 1

На форуме Ваадин кто-то предложил использовать navigator, который решил мою проблему.

Answer 2

Я бы предпочел, чтобы MainUI должен расширить HorizontalSplitPanel, а не пользовательский интерфейс. Для меня странная идея вставить один пользовательский интерфейс в другой.

Answer 3

Вы можете использовать @SpringUI для основного класса, который расширяет интерфейс:

@SpringUI 
@Theme("mytheme") 
@Widgetset("com.MyAppWidgetset") 
@PreserveOnRefresh 
public class MainUI extends UI { 

    private static final long serialVersionUID = -8247521108438815011L; 

    private static Locale locale = VaadinSession.getCurrent().getLocale(); 
    @Autowired 
    private ToolBoxMessageSource messageSource; 

    @Autowired 
    private SpringViewProvider springViewProvider; 

    public MainUI() { 

    } 

//Initializes navigator with SpringViewProvider and add all existing 
//and ui specific assigned views to navigator. 

    @Override 
    protected void init(VaadinRequest vaadinRequest) { 
    Navigator navigator = new Navigator(this, this); 
    // Adding springViewProvider for spring autowiring 
    navigator.addProvider(springViewProvider); 
    // Adding all views for navigation 
    navigator.addView(LoginView.NAME, LoginView.class); 
    navigator.addView(MainView.NAME, MainView.class); 
    navigator.addView(MailToolView.NAME, MailToolView.class); 
    navigator.addView(AdminView.NAME, AdminView.class); 
    navigator.addView(EditRecipientView.NAME, EditRecipientView.class); 
    navigator.addView(EditRecipientsView.NAME, EditRecipientsView.class); 
    navigator.addView(ServerView.NAME, ServerView.class); 
    navigator.addView(TestJobView.NAME, TestJobView.class); 
    navigator.addView("", new LoginView()); 
    navigator.navigateTo(LoginView.NAME); 
    navigator.setErrorView(LoginView.class); 

    // security: if user changes view check if the user has the required rights 
    navigator.addViewChangeListener(new ViewChangeListener() { 
    private static final long serialVersionUID = 7330051193056583546L; 

    @Override 
    public boolean beforeViewChange(ViewChangeEvent event) { 
    Toolbox toolbox = getSession().getAttribute(Toolbox.class); 
    if (TbRightManagement.checkAccess(event.getNewView().getClass(), toolbox)) { 
     return true; 
    } else { 
     if (toolbox != null) { 
     TBNotification.show(messageSource.getMessage("access.denied.title", locale), 
      messageSource.getMessage("access.denied.no_permissions.msg", locale), 
      Type.ERROR_MESSAGE); 
     navigator.navigateTo(MainView.NAME); 
     return false; 
     } else { 
     TBNotification.show(messageSource.getMessage("access.denied.title", locale), 
      messageSource.getMessage("access.denied.not_loggedin.msg", locale), 
      Type.ERROR_MESSAGE); 
     navigator.navigateTo(LoginView.NAME); 
     return false; 
     } 
    } 
    } 

    @Override 
    public void afterViewChange(ViewChangeEvent event) {} 
}); 
} 
} 

И для других взглядов, в качестве примера EditRecipientsView должен быть @SpringView, который расширяет Vaadin Designer и реализует Vaadin View.

@SpringView(name = EditRecipientsView.NAME) 
@Theme("mytheme") 
@TbRight(loggedIn = true, mailTool = true) 
public class EditRecipientsView extends RecipientsDesign implements View { 

private static final long serialVersionUID = 1L; 
public static final String NAME = "editRecipients"; 

private static Locale locale = VaadinSession.getCurrent().getLocale(); 

private BeanItemContainer<Recipient> recipientContainer; 

private Uploader uploader; 

@Autowired 
private ToolBoxMessageSource messageSource; 

    public EditRecipientsView() { 
    super(); 
    } 
    //Initializes the ui components of the recipient view. 
    @PostConstruct 
    public void init() { 
    btn_addRecipient.addClickListener(e -> { MainUI.getCurrent().getNavigator().navigateTo(EditRecipientView.NAME);}); 
    } 
    //Handling data when entering this view. 
    @Override 
    public void enter(ViewChangeEvent event) { 
    if (getSession().getAttribute(UIMailing.class) != null) { 
    List<Recipient> recipientList = getSession().getAttribute(UIMailing.class).getRecipients(); 
    if (recipientList != null) { 
     recipientContainer.removeAllItems(); 
    } else { 
     recipientList = new ArrayList<Recipient>(); 
    } 
    recipientContainer.addAll(recipientList); 
    recipient_table.sort(new Object[] {"foreName", "lastName"}, new boolean[] {true, true}); 
    } 
    } 
}