Add even on Button made on Composite UI

I am very much new with Vaadin. I have made buttons on Composite UI and now I want to call another compositeUI (loginUI) on the button click. What should I do and where should I write the click event. I tried but failed. Below are my code

public class Logon extends CustomComponent {
    @AutoGenerated
    private AbsoluteLayout mainLayout;

    @AutoGenerated
    private Label welcome;

    @AutoGenerated
    private HorizontalLayout horizontalLayout_2;

    @AutoGenerated
    private Button registerButton;

    @AutoGenerated
    private Button loginButton;

    /*- VaadinEditorProperties={"grid":"RegularGrid,20","showGrid":true,"snapToGrid":true,"snapToObject":true,"movingGuides":false,"snappingDistance":10} */
    final static Logger logger = Logger.getLogger(Logon.class);

    /**
     * The constructor should first build the main layout, set the
     * composition root and then do any custom initialization.
     *
     * The constructor will not be automatically regenerated by the
     * visual editor.
     */
    public Logon() {
        buildMainLayout();
        setCompositionRoot(mainLayout);
        // TODO add user code here
        logger.info(resources.org.tu.strike4cash.LogonConf.buttonClickA);
        LoginUI loginUI = new LoginUI();
    }
    
    @AutoGenerated
    private AbsoluteLayout buildMainLayout() {
        // common part: create layout
        mainLayout = new AbsoluteLayout();
        mainLayout.setImmediate(false);
        mainLayout.setWidth("100%");
        mainLayout.setHeight("100%");
        
        // top-level component properties
        setWidth("100.0%");
        setHeight("100.0%");
        
        // horizontalLayout_2
        horizontalLayout_2 = buildHorizontalLayout_2();
        mainLayout.addComponent(horizontalLayout_2, "top:90.0px;right:348.0px;bottom:334.0px;left:120.0px;");
        
        // welcome
        welcome = new Label();
        welcome.setCaption("Welcome to Strike4Cash");
        welcome.setImmediate(false);
        welcome.setWidth("-1px");
        welcome.setHeight("100.0%");
        welcome.setValue("Earn cash in simple click");
        mainLayout.addComponent(welcome, "top:60.0px;bottom:374.0px;left:431.0px;");
        
        return mainLayout;
    }

    @AutoGenerated
    private HorizontalLayout buildHorizontalLayout_2() {
        // common part: create layout
        horizontalLayout_2 = new HorizontalLayout();
        horizontalLayout_2.setImmediate(false);
        horizontalLayout_2.setWidth("100.0%");
        horizontalLayout_2.setHeight("100.0%");
        horizontalLayout_2.setMargin(false);
        
        // loginButton
        loginButton = new Button();
        loginButton.setCaption("Login");
        loginButton.setImmediate(true);
        loginButton.setWidth("100.0%");
        loginButton.setHeight("-1px");
        horizontalLayout_2.addComponent(loginButton);
        horizontalLayout_2.setExpandRatio(loginButton, 1.0f);
        
        // registerButton
        registerButton = new Button();
        registerButton.setCaption("Register");
        registerButton.setImmediate(true);
        registerButton.setWidth("100.0%");
        registerButton.setHeight("-1px");
        horizontalLayout_2.addComponent(registerButton);
        horizontalLayout_2.setExpandRatio(registerButton, 1.0f);
        
        return horizontalLayout_2;
    }
    
}

Are you using the old and deprecated Visual Designer with Eclipse? I strongly recommend Vaadin Designer instead (commercial product).

Anyways using Navigator is a good way to implement navigation. In your UI class init method. 

@Override
    protected void init(VaadinRequest vaadinRequest) {
        // ....
                Navigator navigator = new Navigator(this, this);
        navigator.addView("someview", SomeView.class);
        navigator.addView("anotherview", AnotherView.class);
        setNavigator(navigator);
        if ("".equals(navigator.getState())) {
            navigator.navigateTo("someview");
        }
    }

Using navigator requires your views to implement com.navigator.View interface.
        

Yes I am using old deprecated Visual Designer, I have applied for Student Key but no one ever replied to me.

Did you try to use Navigator?

Sorry to hear no one answered your application. The instructions for non-commercial license key applications has been clarified to explain that due to high amount of requests, applications must be done by the teacher / faculty member. 

I copied the latest instructions from /pro-tools and they are the following

• Application email must be sent from the official domain provided by the institute
• Application for an educational institute needs to be done by an employee of the institute (not students). If you are a student, you should ask a professor or an employee at the educational institute to request the licenses
• Please provide a brief description of the project

Well if at first Navigator seems too difficult to use, you can always call 

loginButton.addClickListener(new ClickListener() {
            @Override
            public void buttonClick(ClickEvent event) {
                UI.getCurrent().setContent(new LoginUI());
            }
        });

Wow, This was easy but haven't found on Google. Problem Solved. Thanks for the Help Hayry..  As I said I am new to Vaadin. I might will disturb you all Pros. :)

It was great help!