5.5.2.2.2. BoxLayout

BoxLayout is a container with sequential placement of components.

There are three types of BoxLayout, identified by the XML-elements:

  • hbox − components are placed horizontally.

    gui hbox 
    <hbox spacing="true" margin="true">
    <dateField datasource="orderDs" property="date"/>
    <lookupField datasource="orderDs" property="customer" optionsDatasource="customersDs"/>
    <textField datasource="orderDs" property="amount"/>
</hbox>

  • vbox − components are placed vertically. vbox has 100% width by default.

    gui vbox 
    <vbox spacing="true" margin="true">
    <dateField datasource="orderDs" property="date"/>
    <lookupField datasource="orderDs" property="customer" optionsDatasource="customersDs"/>
    <textField datasource="orderDs" property="amount"/>
</vbox>

  • flowBox − components are placed horizontally with line wrapping. If there is not enough space in a line, the components that do not fit will be displayed in the next line (the behavior is similar to Swing FlowLayout).

    gui flowbox 
    <flowBox spacing="true" margin="true">
    <dateField datasource="orderDs" property="date"/>
    <lookupField datasource="orderDs" property="customer" optionsDatasource="customersDs"/>
    <textField datasource="orderDs" property="amount"/>
</flowBox>

In Web Client with a Halo-based theme, BoxLayout may be used to create enhanced composite layouts. The stylename attribute with card or well value along with stylename="v-panel-caption" for an enclosed container will make a component look like Vaadin Panel.

  • card style name makes a layout look like a card.

  • well style makes the card look "sunken" with shaded background.

gui boxlayout 
<vbox stylename="well"
      height="200px"
      width="300px"
      expand="message"
      spacing="true">
    <hbox stylename="v-panel-caption"
          width="100%">
        <label value="Widget caption"/>
        <button align="MIDDLE_RIGHT"
                icon="font-icon:EXPAND"
                stylename="borderless-colored"/>
    </hbox>
    <textArea id="message"
              inputPrompt="Enter your message here..."
              width="280"
              align="MIDDLE_CENTER"/>
    <button caption="Send message"
            width="100%"/>
</vbox>

The getComponent() method allows you to obtain a child component of BoxLayout by its index:

Button button = (Button) hbox.getComponent(0);

You can use keyboard shortcuts in BoxLayout. Set the shortcut and the action to be performed using the addShortcutAction() method:

flowBox.addShortcutAction(new ShortcutAction("SHIFT-A", shortcutTriggeredEvent ->
        showNotification("SHIFT-A action" )));
Attributes of hbox, vbox, flowBox

align - enable - expand - height - id - margin - spacing - stylename - visible - width

API

add - addLayoutClickListener - addShortcutAction - getComponent - getComponentNN - getComponents - getMargin - getOwnComponent - getOwnComponents - indexOf - remove - removeAll - setMargin - setSpacing