--- title: Sub-Windows order: 7 layout: page --- [[layout.sub-window]] = Sub-Windows ifdef::web[] [.sampler] image:{live-demo-image}[alt="Live Demo", link="http://demo.vaadin.com/sampler/#ui/structure/window"] endif::web[] __Sub-windows__ are floating panels within a native browser window. Unlike native browser windows, sub-windows are managed by the client-side runtime of Vaadin using HTML features. Vaadin allows opening, closing, resizing, maximizing and restoring sub-windows, as well as scrolling the window content. [[figure.layout.sub-window.basic]] .A Sub-Window image::img/subwindow-basic.png[] Sub-windows are typically used for __Dialog Windows__ and __Multiple Document Interface__ applications. Sub-windows are by default not modal; you can set them modal as described in <>. [[layout.sub-window.openclose]] == Opening and Closing Sub-Windows You can open a new sub-window by creating a new [classname]#Window# object and adding it to the UI with [methodname]#addWindow()#, typically in some event listener. A sub-window needs a content component, which is typically a layout. In the following, we display a sub-window immediately when a UI opens: [source, java] ---- public static class SubWindowUI extends UI { @Override protected void init(VaadinRequest request) { // Some other UI content setContent(new Label("Here's my UI")); // Create a sub-window and set the content Window subWindow = new Window("Sub-window"); VerticalLayout subContent = new VerticalLayout(); subContent.setMargin(true); subWindow.setContent(subContent); // Put some components in it subContent.addComponent(new Label("Meatball sub")); subContent.addComponent(new Button("Awlright")); // Center it in the browser window subWindow.center(); // Open it in the UI addWindow(subWindow); } } ---- The result was shown in <>. Sub-windows by default have undefined size in both dimensions, so they will shrink to fit the content. The user can close a sub-window by clicking the close button in the upper-right corner of the window. The button is controlled by the __closable__ property, so you can disable it with [methodname]#setClosable(false)#. You can also use keyboard shortcuts for closing a sub-window. You can manage the shortcuts with the [methodname]#addCloseShortcut()#, [methodname]#removeCloseShortcut()#, [methodname]#removeAllCloseShortcuts()#, [methodname]#hasCloseShortcut()# and [methodname]#getCloseShortcuts()# methods. You close a sub-window also programmatically by calling the [methodname]#close()# for the sub-window, typically in a click listener for an [guibutton]#OK# or [guibutton]#Cancel# button. You can also call [methodname]#removeWindow()# for the current [classname]#UI#. ifdef::web[] [[layout.sub-window.openclose.example]] === Sub-Window Management Usually, you would extend the [classname]#Window# class for your specific sub-window as follows: [source, java] ---- // Define a sub-window by inheritance class MySub extends Window { public MySub() { super("Subs on Sale"); // Set window caption center(); // Some basic content for the window VerticalLayout content = new VerticalLayout(); content.addComponent(new Label("Just say it's OK!")); content.setMargin(true); setContent(content); // Disable the close button setClosable(false); // Trivial logic for closing the sub-window Button ok = new Button("OK"); ok.addClickListener(new ClickListener() { public void buttonClick(ClickEvent event) { close(); // Close the sub-window } }); content.addComponent(ok); } } ---- You could open the window as follows: [source, java] ---- // Some UI logic to open the sub-window final Button open = new Button("Open Sub-Window"); open.addClickListener(new ClickListener() { public void buttonClick(ClickEvent event) { MySub sub = new MySub(); // Add it to the root component UI.getCurrent().addWindow(sub); } }); ---- endif::web[] [[layout.sub-window.position]] == Window Positioning When created, a sub-window will have an undefined default size and position. You can specify the size of a window with [methodname]#setHeight()# and [methodname]#setWidth()# methods. You can set the position of the window with [methodname]#setPositionX()# and [methodname]#setPositionY()# methods. [source, java] ---- // Create a new sub-window mywindow = new Window("My Dialog"); // Set window size. mywindow.setHeight("200px"); mywindow.setWidth("400px"); // Set window position. mywindow.setPositionX(200); mywindow.setPositionY(50); UI.getCurrent().addWindow(mywindow); ---- [[layout.sub-window.scrolling]] == Scrolling Sub-Window Content ((("scroll bars", id="term.layout.sub-window.scrolling.scrollbars", range="startofrange"))) If a sub-window has a fixed or percentual size and its content becomes too big to fit in the content area, a scroll bar will appear for the particular direction. On the other hand, if the sub-window has undefined size in the direction, it will fit the size of the content and never get a scroll bar. Scroll bars in sub-windows are handled with regular HTML features, namely [literal]#++overflow: auto++# property in CSS. ((("overflow"))) ((("[interfacename]#Scrollable#"))) As [classname]#Window# extends [classname]#Panel#, windows are also [interfacename]#Scrollable#. Note that the interface defines __programmatic scrolling__, not scrolling by the user. Please see <>. (((range="endofrange", startref="term.layout.sub-window.scrolling.scrollbars"))) [[layout.sub-window.modal]] == Modal Sub-Windows A modal window is a sub-window that prevents interaction with the other UI. Dialog windows, as illustrated in <>, are typical cases of modal windows. The advantage of modal windows is limiting the scope of user interaction to a sub-task, so changes in application state are more limited. The disadvantage of modal windows is that they can restrict workflow too much. You can make a sub-window modal with [methodname]#setModal(true)#. [[figure.layout.sub-window.modal]] .Modal Sub-Window image::img/subwindow-modal.png[] Depending on the theme, the parent window may be grayed when the modal window is open. [WARNING] .Security Warning ==== Modality of child windows is purely a client-side feature and can be circumvented with client-side attack code. You should not trust in the modality of child windows in security-critical situations such as login windows. ====