Class WContainerWidget

Direct Known Subclasses:
IndexContainerWidget, WAnchor, WDeferred, WFileDropWidget, WGroupBox, WMenuItem, WStackedWidget, WTableCell

public class WContainerWidget
extends WInteractWidget
A widget that holds and manages child widgets.

A WContainerWidget acts as a container for child widgets. Child widgets may be added directly to the container or using a layout manager.

Use addWidget() or pass the container as constructor argument to a widget to directly add children to the container, without using a layout manager. In that case, CSS-based layout is used, and the resulting display is determined by properties of the children and the container. By default, a WContainerWidget is displayed as a block and manages its children within a rectangle. Inline child widgets are layed out in lines, wrapping around as needed, while block child widgets are stacked vertically. The container may add padding at the container edges using setPadding(), and provide alignment of contents using setContentAlignment(). A container is rendered by default using a HTML div tag, but this may be changed to an HTML ul or ol tag to make use of other CSS layout techniques, using setList(). In addition, specializations of this class as implemented by WAnchor, WGroupBox, WStackedWidget and WTableCell provide other alternative rendering of the container.

When setting the WContainerWidget inline the container only acts as a conceptual container, offering a common style to its children. Inline children are still layed out inline within the flow of the parent container of this container, as if they were inserted directly into that parent container. Block children are then not allowed (according to the HTML specification).

To use a layout manager instead of CSS-based layout, use setLayout() or pass the container as constructor argument to a layout manager. In that case you should not define any padding for the container, and widgets and nested layout managers must be added to the layout manager, instead of to the container directly.

Usage example:


 // Example 1:
 // Instantiate a container widget and add some children whose layout
 // is governed based on HTML/CSS rules.
 WContainerWidget container1 = new WContainerWidget();
 container1.addWidget(new WText("Some text"));
 container1.addWidget(new WImage("images/img.png"));
 WContainerWidget child3 = new WContainerWidget(container1);

 // Example 2:
 // Instantiate a container widget which uses a layout manager
 WContainerWidget container2 = new WContainerWidget();
 // give the container a fixed height
 container2.resize(WLength.Auto, new WLength(600));

 WVBoxLayout layout = new WVBoxLayout();
 layout.addWidget(new WText("Some text"));
 layout.addWidget(new WImage("images/img.png"));

 container2.setLayout(layout);      // set the layout to the container.

 

When using a layout manager, you need to carefully consider the alignment of the layout manager with respect to the container: when the container's height is unconstrained (not specified explicitly using WWebWidget#resize() or a style class, and the container is not included in a layout manager), you should pass AlignmentFlag.Top to setLayout().

CSS

Depending on its configuration and usage, the widget corresponds to the following HTML tags:

  • By default, the widget corresponds to a <div> tag.
  • When configured with setInline(true), the widget corresponds to a <span> .
  • When configured with setList(true), the widget corresponds to a <ul>.
  • When configured with setList(true, true), the widget corresponds to a <ol> .
  • When inserted into a container widget that isList(), the widget corresponds to a <li>.

This widget does not provide styling, and can be styled using inline or external CSS as appropriate.

  • Constructor Details

  • Method Details

    • remove

      public void remove()
      Destructor.
      Overrides:
      remove in class WInteractWidget
      See Also:
      WWidget.removeWidget(WWidget widget)
    • setLayout

      public void setLayout​(WLayout layout)
      Sets a layout manager for the container.

      Note that you can nest layout managers inside each other, to create a complex layout hierarchy.

      If a previous layout manager was already set, it is first deleted. In that case, you will need to make sure that you either readd all widgets that were part of the previous layout to the new layout, or delete them, to avoid memory leaks.

      See Also:
      getLayout()
    • getLayout

      public WLayout getLayout()
      Returns the layout manager that was set for the container.

      If no layout manager was previously set using setLayout(WLayout *), 0 is returned.

    • addWidget

      public void addWidget​(WWidget widget)
      Adds a child widget to this container.

      The widget is appended to the list of children, and thus also layed-out at the end.

      If, for some reason, you want to be in control of the lifetime of the widget, you can retrieve a unique_ptr with WObject::removeChild()

    • insertBefore

      public void insertBefore​(WWidget widget, WWidget before)
      Inserts a child widget in this container, before another widget.

      The widget is inserted at the place of the before widget, and subsequent widgets are shifted.

      If, for some reason, you want to be in control of the lifetime of the widget, you can regain ownership of the widget (without any functional implication) using WObject::removeChild()

    • insertWidget

      public void insertWidget​(int index, WWidget widget)
      Inserts a child widget in this container at given index.

      The widget is inserted at the given index, and subsequent widgets are shifted.

      If, for some reason, you want to be in control of the lifetime of the widget, you can regain ownership of the widget (without any functional implication) using WObject::removeChild()

    • removeWidget

      public WWidget removeWidget​(WWidget widget)
      Removes a child widget from this container.

      If the WContainerWidget owns the given widget (i.e. if it was added with addWidget() or insertWidget() and not removed with WObject::removeChild()), a unique_ptr to this widget is returned. Otherwise, this returns nullptr.

      Overrides:
      removeWidget in class WWidget
    • clear

      public void clear()
      Removes all widgets.

      This removes all children that have been added to this container. If a layout was set, also the layout manager is cleared.

    • getIndexOf

      public int getIndexOf​(WWidget widget)
      Returns the index of a widget.
    • getWidget

      public WWidget getWidget​(int index)
      Returns the widget at index
    • getCount

      public int getCount()
      Returns the number of widgets in this container.
    • setContentAlignment

      public void setContentAlignment​(java.util.EnumSet<AlignmentFlag> alignment)
      Specifies how child widgets must be aligned within the container.

      For a WContainerWidget, only specifes the horizontal alignment of child widgets. Note that there is no way to specify vertical alignment: children are always pushed to the top of the container.

      For a WTableCell, this may also specify the vertical alignment. The default alignment is (AlignmentFlag.Top | AlignmentFlag.Left).

    • setContentAlignment

      public final void setContentAlignment​(AlignmentFlag alignmen, AlignmentFlag... alignment)
      Specifies how child widgets must be aligned within the container.

      Calls setContentAlignment(EnumSet.of(alignmen, alignment))

    • setPadding

      public void setPadding​(WLength length, java.util.EnumSet<Side> sides)
      Sets padding inside the widget.

      Setting padding has the effect of adding distance between the widget children and the border.

    • setPadding

      public final void setPadding​(WLength length, Side side, Side... sides)
      Sets padding inside the widget.

      Calls setPadding(length, EnumSet.of(side, sides))

    • setPadding

      public final void setPadding​(WLength length)
      Sets padding inside the widget.

      Calls setPadding(length, Side.AllSides)

    • getPadding

      public WLength getPadding​(Side side)
      Returns the padding set for the widget.

      See Also:
      setPadding(WLength length, EnumSet sides)
    • getContentAlignment

      public java.util.EnumSet<AlignmentFlag> getContentAlignment()
      Returns the alignment of children.

      See Also:
      setContentAlignment(EnumSet alignment)
    • setOverflow

      public void setOverflow​(Overflow value, java.util.EnumSet<Orientation> orientation)
      Sets how overflow of contained children must be handled.
    • setOverflow

      public final void setOverflow​(Overflow value, Orientation orientatio, Orientation... orientation)
      Sets how overflow of contained children must be handled.

      Calls setOverflow(value, EnumSet.of(orientatio, orientation))

    • setOverflow

      public final void setOverflow​(Overflow value)
      Sets how overflow of contained children must be handled.

      Calls setOverflow(value, EnumSet.of (Orientation.Horizontal, Orientation.Vertical))

    • setList

      public void setList​(boolean list, boolean ordered)
      Renders the container as an HTML list.

      Setting renderList to true will cause the container to be using an HTML <ul> or <ol> type, depending on the value of orderedList. This must be set before the initial render of the container. When set, any contained WContainerWidget will be rendered as an HTML <li>. Adding non-WContainerWidget children results in unspecified behaviour.

      Note that CSS default layout rules for <ul> and <ol> add margin and padding to the container, which may look odd if you do not use bullets.

      By default, a container is rendered using a <div> element.

      See Also:
      isList(), isOrderedList(), isUnorderedList()
    • setList

      public final void setList​(boolean list)
      Renders the container as an HTML list.

      Calls setList(list, false)

    • isList

      public boolean isList()
      Returns if this container is rendered as a List.

      See Also:
      setList(boolean list, boolean ordered), isOrderedList(), isUnorderedList()
    • isUnorderedList

      public boolean isUnorderedList()
      Returns if this container is rendered as an Unordered List.

      See Also:
      setList(boolean list, boolean ordered), isList(), isOrderedList()
    • isOrderedList

      public boolean isOrderedList()
      Returns if this container is rendered as an Ordered List.

      See Also:
      setList(boolean list, boolean ordered), isList(), isUnorderedList()
    • scrolled

      public EventSignal1<WScrollEvent> scrolled()
      Event signal emitted when scrolling in the widget.

      This event is emitted when the user scrolls in the widget (for setting the scroll bar policy, see setOverflow()). The event conveys details such as the new scroll bar position, the total contents height and the current widget height.

      See Also:
      setOverflow(Overflow value, EnumSet orientation)
    • getScrollTop

      public int getScrollTop()
      return the number of pixels the container is scrolled horizontally

      This value is only set if setOverflow() has been called

      See Also:
      setOverflow(Overflow value, EnumSet orientation), getScrollLeft()
    • getScrollLeft

      public int getScrollLeft()
      return the number of pixels the container is scrolled vertically

      This value is only set if setOverflow() has been called

      See Also:
      setOverflow(Overflow value, EnumSet orientation), getScrollTop()
    • setGlobalUnfocused

      public void setGlobalUnfocused​(boolean b)
    • isGlobalUnfocussed

      public boolean isGlobalUnfocussed()
    • parentResized

      protected void parentResized​(WWidget parent, java.util.EnumSet<Orientation> directions)
      Overrides:
      parentResized in class WWebWidget
    • getDomChanges

      protected void getDomChanges​(java.util.List<DomElement> result, WApplication app)
      Description copied from class: WWebWidget
      Get DOM changes for this widget.

      This is an internal function, and should not be called directly, or be overridden!

      Overrides:
      getDomChanges in class WWebWidget
    • iterateChildren

      protected void iterateChildren​(HandleWidgetMethod method)
      Overrides:
      iterateChildren in class WWebWidget
    • createDomElement

      protected DomElement createDomElement​(WApplication app)
      Description copied from class: WWebWidget
      Create DOM element for widget.

      This is an internal function, and should not be called directly, or be overridden!

      Overrides:
      createDomElement in class WWebWidget
    • setFormData

      protected void setFormData​(WObject.FormData formData)
      Overrides:
      setFormData in class WObject