eu.webtoolkit.jwt
Class WContainerWidget

java.lang.Object
  eu.webtoolkit.jwt.WObject
      eu.webtoolkit.jwt.WWidget
          eu.webtoolkit.jwt.WWebWidget
              eu.webtoolkit.jwt.WInteractWidget
                  eu.webtoolkit.jwt.WContainerWidget

Direct Known Subclasses:

WAnchor, WGroupBox, WOverlayLoadingIndicator, 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 AlignTop 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.

Nested Class Summary

static class

WContainerWidget.Overflow How to handle overflow of inner content.

Constructor Summary

WContainerWidget()
Creates a container with optional parent.

WContainerWidget(WContainerWidget parent)
Creates a container with optional parent.

Method Summary

void	addWidget(WWidget widget) Adds a child widget to this container.
void	clear() Removes and deletes all child widgets.
java.util.EnumSet<AlignmentFlag>	getContentAlignment() Returns the alignment of children.
int	getCount() Returns the number of widgets in this container.
int	getIndexOf(WWidget widget) Returns the index of a widget.
WLayout	getLayout() Returns the layout manager that was set for the container.
WLength	getPadding(Side side) Returns the padding set for the widget.
WWidget	getWidget(int index) Returns the widget at index.
void	insertBefore(WWidget widget, WWidget before) Inserts a child widget in this container, before another widget.
void	insertWidget(int index, WWidget widget) Inserts a child widget in this container at given index.
boolean	isList() Returns if this container is rendered as a List.
boolean	isOrderedList() Returns if this container is rendered as an Ordered List.
boolean	isUnorderedList() Returns if this container is rendered as an Unordered List.
void	remove() Destructor.
void	removeWidget(WWidget widget) Removes a child widget from this container.
EventSignal1<WScrollEvent>	scrolled() Event signal emitted when scrolling in the widget.
void	setContentAlignment(AlignmentFlag alignmen, AlignmentFlag... alignment) Specifies how child widgets must be aligned within the container.
void	setContentAlignment(java.util.EnumSet<AlignmentFlag> alignment) Specifies how child widgets must be aligned within the container.
void	setLayout(WLayout layout) Sets a layout manager for the container.
void	setLayout(WLayout layout, AlignmentFlag alignmen, AlignmentFlag... alignment) Sets a layout manager for the container.
void	setLayout(WLayout layout, java.util.EnumSet<AlignmentFlag> alignment) Sets a layout manager for the container.
void	setList(boolean list) Renders the container as an HTML list.
void	setList(boolean list, boolean ordered) Renders the container as an HTML list.
void	setOverflow(WContainerWidget.Overflow value) Sets how overflow of contained children must be handled.
void	setOverflow(WContainerWidget.Overflow value, java.util.EnumSet<Orientation> orientation) Sets how overflow of contained children must be handled.
void	setOverflow(WContainerWidget.Overflow value, Orientation orientatio, Orientation... orientation) Sets how overflow of contained children must be handled.
void	setPadding(WLength length) Sets padding inside the widget.
void	setPadding(WLength length, java.util.EnumSet<Side> sides) Sets padding inside the widget.
void	setPadding(WLength length, Side side, Side... sides) Sets padding inside the widget.

Methods inherited from class eu.webtoolkit.jwt.WInteractWidget

clicked, doubleClicked, enterPressed, escapePressed, gestureChanged, gestureEnded, gestureStarted, isEnabled, keyPressed, keyWentDown, keyWentUp, load, mouseDragged, mouseMoved, mouseWentDown, mouseWentOut, mouseWentOver, mouseWentUp, mouseWheel, propagateSetEnabled, setDraggable, setDraggable, setDraggable, setDraggable, touchEnded, touchMoved, touchStarted

Methods inherited from class eu.webtoolkit.jwt.WWebWidget

addStyleClass, callJavaScriptMember, childrenChanged, doJavaScript, domCanBeSaved, enableAjax, escapeText, escapeText, escapeText, escapeText, find, getAttributeValue, getChildren, getClearSides, getDecorationStyle, getFloatSide, getHeight, getId, getJavaScriptMember, getLineHeight, getMargin, getMaximumHeight, getMaximumWidth, getMinimumHeight, getMinimumWidth, getOffset, getPositionScheme, getStyleClass, getTabIndex, getToolTip, getVerticalAlignment, getVerticalAlignmentLength, getWidth, isDisabled, isHidden, isHiddenKeepsGeometry, isInline, isLoaded, isPopup, isRendered, isVisible, jsStringLiteral, jsStringLiteral, refresh, removeScript, removeStyleClass, resize, setAttributeValue, setClearSides, setDecorationStyle, setDisabled, setFloatSide, setHidden, setHiddenKeepsGeometry, setId, setInline, setJavaScriptMember, setLineHeight, setLoadLaterWhenInvisible, setMargin, setMaximumSize, setMinimumSize, setOffsets, setPopup, setPositionScheme, setSelectable, setStyleClass, setTabIndex, setToolTip, setVerticalAlignment, updateSignalConnection

Methods inherited from class eu.webtoolkit.jwt.WWidget

acceptDrops, acceptDrops, addCssRule, addCssRule, addStyleClass, animateHide, animateShow, boxBorder, boxPadding, containsExposed, disable, dropEvent, enable, getDrop, getJsRef, getParent, hide, htmlText, isLayoutSizeAware, layoutSizeChanged, positionAt, positionAt, removeStyleClass, resize, setClearSides, setHeight, setHidden, setLayoutSizeAware, setMargin, setMargin, setMargin, setMargin, setMargin, setOffsets, setOffsets, setOffsets, setOffsets, setOffsets, setToolTip, setVerticalAlignment, setWidth, show, stopAcceptDrops, toggleStyleClass, toggleStyleClass, tr

Methods inherited from class eu.webtoolkit.jwt.WObject

getObjectName, setObjectName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WContainerWidget

public WContainerWidget(WContainerWidget parent)

Creates a container with optional parent.

WContainerWidget

public WContainerWidget()

Creates a container with optional parent.

Calls this((WContainerWidget)null)

Method Detail

remove

public void remove()

Destructor.

Overrides:

remove in class WInteractWidget

See Also:

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.

The layout manager arranges children in the entire width and height of the container. This is equivalent to setLayout(layout, AlignJustify)

See Also:

getLayout(), setLayout(WLayout layout, EnumSet alignment)

setLayout

public void setLayout(WLayout layout,
                      java.util.EnumSet<AlignmentFlag> alignment)

Sets a layout manager for the container.

The alignment argument determines how the layout is aligned inside the container. By default, the layout manager arranges children over the entire width and height of the container, corresponding to a value of AlignJustify. This requires that the container has a specified height (either because it is managed by another layout manager, is the root container widget, or has a height set).

In general, alignment is the logical OR of a horizontal and a vertical flag:

• The horizontal alignment option may be one of AlignmentFlag.AlignLeft, AlignmentFlag.AlignCenter, AlignmentFlag.AlignRight, or AlignmentFlag.AlignJustify.
• The vertical alignment option may be '0' (corresponding to vertical justification to the full height), or AlignmentFlag.AlignTop.

When using a horizontal alingment different from AlignmentFlag.AlignJustify, and a vertical alignment different from '0', the widget is sized in that direction to fit the contents, instead of the contents being adjusted to the widget size. This is useful when the container does not have a specific size in that direction and when the layout manager does not contain any widgets that wish to consume all remaining space in that direction.

Only a single layout manager may be set. If you want to replace the current layout manager, you have to erase all contents first using clear(), which also deletes the layout manager.

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

The widget will take ownership of layout.

See Also:

getLayout()

setLayout

public final void setLayout(WLayout layout,
                            AlignmentFlag alignmen,
                            AlignmentFlag... alignment)

Sets a layout manager for the container.

Calls setLayout(layout, EnumSet.of(alignmen, alignment))

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.

See Also:

setLayout(WLayout layout)

addWidget

public void addWidget(WWidget widget)

Adds a child widget to this container.

This is equivalent to passing this container as the parent when constructing the child. The widget is appended to the list of children, and thus also layed-out at the end.

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.

See Also:

insertWidget(int index, WWidget widget)

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.

See Also:

insertBefore(WWidget widget, WWidget before)

removeWidget

public void removeWidget(WWidget widget)

Removes a child widget from this container.

This removes the widget from this container, but does not delete the widget !

clear

public void clear()

Removes and deletes all child widgets.

This deletes all children that have been added to this container.

If a layout was set, also the layout manager is deleted.

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.AlignTop | AlignmentFlag.AlignLeft).

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.All)

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(WContainerWidget.Overflow value,
                        java.util.EnumSet<Orientation> orientation)

Sets how overflow of contained children must be handled.

This is an alternative (CSS-ish) way to configure scroll bars on a container widget, compared to wrapping inside a WScrollArea.

Unlike WScrollArea, horizontal scrolling does not work reliably when the container widget is inserted in a layout manager: the layout manager will overflow rather than use scrollbars for this container widget. A solution then is to use WScrollArea instead.

See Also:

WScrollArea

setOverflow

public final void setOverflow(WContainerWidget.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(WContainerWidget.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(WContainerWidget.Overflow value, EnumSet orientation)