display no thing on screen

Dear all,
I have create vaadin demo to display an button on screen, but it display no thing, hope you help me in this problem,

My application :

public class StudentApplication extends Application {
private static final long serialVersionUID = 1L;
@Override
public void init() {
setTheme(“mythemse”);
final Window w = new Window();
setMainWindow(w);
setContent(new LoginView());
}
public void setContent(LoginView loginView) {
final Window window = new Window();
window.setCaption(“Login”);
window.setContent(loginView);
}
}

My View:

public class LoginView extends Panel {
private static final long serialVersionUID = 1L;
private final CustomLayout loginLayout = new CustomLayout(“login”);
public LoginView(){
initalize();
this.setSizeFull();
}
public void initalize() {
Button loginButton = new Button(“TEST”);
loginLayout.addComponent(loginButton,“testlogin”);
this.setContent(loginLayout);
}
}

My html : webapp/VAADIN/themses/mythemses/layouts/login.html

thankyou very much

You’re creating two windows - main window and the one containing your LoginView. The first one is set properly, but the second window is not added anywhere in your code. Either add the second window with an addWindow(…) call, or remove the second window completely and place your LoginView directly into the main window.