Package eu.webtoolkit.jwt

Class WWidget

java.lang.Object
eu.webtoolkit.jwt.WObject
eu.webtoolkit.jwt.WWidget
Direct Known Subclasses:
WCompositeWidget, WWebWidget
public abstract class WWidget extends WObject
The abstract base class for a user-interface component.

The user-interface is organized in a tree structure, in which each node is a widget. All widgets, except for the application's root widget and dialogs, have a parent which is usually a WContainerWidget.

This is an abstract base class. Implementations derive either from the abstract WWebWidget (for basic widgets with a direct HTML counter-part) or from the abstract WCompositeWidget (for anything else). To add a WWidget to a parent container add the widget to the parent using WContainerWidget#addWidget(). Alternatively, you may add the widget to a layout manager set for a WContainerWidget.

A widget provides methods to manage its decorative style base on CSS. It also provides access to CSS-based layout, which you may not use when the widget is not inserted into a layout manager.

  • Field Details

    • WT_GETEXTRAMS_JS

      protected static String WT_GETEXTRAMS_JS

  • Constructor Details

  • Method Details

    • remove

      public void remove()
      Destructor.

      Deletes a widget and all contained contents.

      Overrides:
      remove in class WObject
      See Also:

    • getParent

      public WWidget getParent()
      Returns the parent widget.

    • getChildren

      public abstract List<WWidget> getChildren()
      Returns child widgets.

      This returns widgets for which widget.getParent() == this.

    • removeWidget

      public WWidget removeWidget(WWidget widget)
      Removes a child widget.

    • removeFromParent

      public WWidget removeFromParent()
      Removes the widget from its parent.

      This is equivalent to getParent().removeWidget(this);

    • setPositionScheme

      public abstract void setPositionScheme(PositionScheme scheme)
      Sets the CSS position scheme.

      Establishes how the widget must be layed-out relative to its siblings. The default position scheme is PositionScheme.Static.

      This applies to CSS-based layout.

      See Also:

    • getPositionScheme

      public abstract PositionScheme getPositionScheme()
      Returns the CSS position scheme.

      This applies to CSS-based layout.

      See Also:

    • setOffsets

      public abstract void setOffsets(WLength offset, EnumSet<Side> sides)
      Sets CSS offsets for a non-statically positioned widget.

      The argument sides may be a combination of Side.Left, Side.Right, Side.Top, and Side.Bottom.

      This applies only to widgets that have a position scheme that is PositionScheme.Relative, PositionScheme.Absolute, or PositionScheme.Fixed, and has a slightly different meaning for these three cases.

      For a relatively positioned widget, an offset applies relative to the position the widget would have when layed-out using a static position scheme. The widget may be shifted to the left or right by specifying an offset for the left or right) side. The widget may be shifted vertically, by specifying an offset for the top or bottom side.

      For an absolutely positioned widget, an offset specifies a distance of the corresponding side of the widget with respect to the corresponding side of the reference parent widget. Thus, setting all offsets to 0 result in a widget that spans the entire reference widget. The reference parent widget is the first ancestor widget that is a table cell, or a widget with a relative, absolute or fixed position scheme.

      For an fixed positioned widget, an offset specifies a distance of the corresponding side of the widget with respect to the browser window, regardless of scrolling. Thus, setting all offsets to 0 result in a widget that spans the entire browser window.

      This applies to CSS-based layout.

      See Also:

    • setOffsets

      public final void setOffsets(WLength offset, Side side, Side... sides)
      Sets CSS offsets for a non-statically positioned widget.

      Calls setOffsets(offset, EnumSet.of(side, sides))

    • setOffsets

      public final void setOffsets(WLength offset)
      Sets CSS offsets for a non-statically positioned widget.

      Calls setOffsets(offset, Side.AllSides)

    • setOffsets

      public void setOffsets(int pixels, EnumSet<Side> sides)
      Sets CSS offsets for a non-statically positioned widget.

      This is a convenience method for applying offsets in pixel units.

      See Also:

    • setOffsets

      public final void setOffsets(int pixels, Side side, Side... sides)
      Sets CSS offsets for a non-statically positioned widget.

      Calls setOffsets(pixels, EnumSet.of(side, sides))

    • setOffsets

      public final void setOffsets(int pixels)
      Sets CSS offsets for a non-statically positioned widget.

      Calls setOffsets(pixels, Side.AllSides)

    • getOffset

      public abstract WLength getOffset(Side side)
      Returns a CSS offset.

      This applies to CSS-based layout.

      See Also:

    • resize

      public void resize(WLength width, WLength height)
      Resizes the widget.

      Specifies a fixed size for this widget, setting CSS width and height properties. By default a widget has automatic width and height, which sets a size for the widget following CSS rules.

      When the widget is not managed by a layout manager, the automatic (natural) size of a widget depends on whether the widget is a block or inline widget:

      • a block widget takes by default the width of the parent, and the height that it needs based on its contents
      • an inline widget takes the width and height that it needs based on its contents (possibly wrapping over multiple lines). The width and height of an inline widget cannot be changed (by the letter of CSS, although most browsers will react to it in varying ways).

      When inserted in a layout manager, the size set will be used as a widget's preferred size, but the widget may be given a different size by the layout manager based on available space and stretch factors. The actual size given by a layout manager may be retrieved by making the widget "layout size aware", using setLayoutSizeAware(). If you have defined a "wtResize()" JavaScript method for the widget, then this method will also be called.

      The default width and height of a widget is WLength.Auto.

      See Also:

    • resize

      public void resize(int widthPixels, int heightPixels)
      Resizes the widget.

      This is a convenience method for resizing a widget using pixel units.

      See Also:

    • getWidth

      public abstract WLength getWidth()
      Returns the width.

      Returns the width set for this widget. This is not a calculated width, based on layout, but the width as specified with resize().

      This applies to CSS-based layout.

      See Also:

    • setWidth

      public void setWidth(WLength width)
      Sets the width.

      This is a convenience method to change only the width of a widget, and is implemented as: 

      
 resize(width, height())

      See Also:

    • getHeight

      public abstract WLength getHeight()
      Returns the height.

      Returns the height set for this widget. This is not a calculated height, based on layout, but the height as specified previously with resize().

      This applies to CSS-based layout.

      See Also:

    • setHeight

      public void setHeight(WLength height)
      Sets the height.

      This is a convenience method to change only the height of a widget, and is implemented as: 

      
 resize(width(), height)

      This applies to CSS-based layout.

      See Also:

    • setMinimumSize

      public abstract void setMinimumSize(WLength width, WLength height)
      Sets a minimum size.

      Specifies a minimum size for this widget, setting CSS min-width and min-height properties.

      The default minimum width and height is 0. The special value WLength.Auto indicates that the initial width is used as minimum size. A LengthUnit.Percentage size should not be used, as this is (in virtually all cases) undefined behaviour.

      When the widget is inserted in a layout manager, then the minimum size will be taken into account.

      See Also:

    • getMinimumWidth

      public abstract WLength getMinimumWidth()
      Returns the minimum width.

      Returns the minimum width set for this widget with setMinimumSize().

      See Also:

    • getMinimumHeight

      public abstract WLength getMinimumHeight()
      Returns the minimum height.

      Returns the minmum height set for this widget with setMinimumSize().

      See Also:

    • setMaximumSize

      public abstract void setMaximumSize(WLength width, WLength height)
      Sets a maximum size.

      Specifies a maximum size for this widget, setting CSS max-width and max-height properties.

      The default the maximum width and height are WLength.Auto, indicating no maximum size. A LengthUnit.Percentage size should not be used, as this is (in virtually all cases) undefined behaviour.

      When the widget is a container widget that contains a layout manager, then setting a maximum size will have the effect of letting the size of the container to reflect the preferred size of the contents (rather than constraining the size of the children based on the size of the container), up to the specified maximum size.

      See Also:

    • getMaximumWidth

      public abstract WLength getMaximumWidth()
      Returns the maximum width.

      Returns the maximum width set for this widget with setMaximumSize().

      See Also:

    • getMaximumHeight

      public abstract WLength getMaximumHeight()
      Returns the maximum height.

      Returns the minmum height set for this widget with setMaximumSize().

      See Also:

    • positionAt

      public void positionAt(WWidget widget, Orientation orientation, EnumSet<Orientation> adjustOrientations)
      Positions a widget next to another widget.

      Positions this absolutely positioned widget next to another widget. Both widgets must be visible (including all their ancestors). The current widget is shown automatically if needed.

      When orientation = Orientation.Vertical, the widget is displayed below the other widget (or above in case there is not enough room below). It is aligned so that the left edges align (or the right edges if there is not enough room to the right).

      Conversely, when orientation = Orientation.Horizontal, the widget is displayed to the right of the other widget (or to the left in case there is not enough room to the right). It is aligned so that the top edges align (or the bottom edges if there is not enough room below).

      adjustOrientations allows to specify the axes on which the widget can adjust it's position if there is not enough room next to the other widget, breaking the previous rules if necessary. For example, if Orientation.Vertical flag of adjustOrientations is set, and part of the widget would be cut off by the top of the window, the widget would be move downward until the top of the widget is fully visible (or the widget reaches the bottom of the window). In that case, the widget would not be aligned with the other widget, in case orientation = Orientation.Horizontal, or would be displayed over the other widget, in case orientation = Orientation.Vertical.

      Note: This only works if JavaScript is available.

    • positionAt

      public final void positionAt(WWidget widget, Orientation orientation, Orientation adjustOrientation, Orientation... adjustOrientations)
      Positions a widget next to another widget.

      Calls positionAt(widget, orientation, EnumSet.of(adjustOrientation, adjustOrientations))

    • positionAt

      public final void positionAt(WWidget widget)
      Positions a widget next to another widget.

      Calls positionAt(widget, Orientation.Vertical, Orientation.AllOrientations)

    • positionAt

      public final void positionAt(WWidget widget, Orientation orientation)
      Positions a widget next to another widget.

      Calls positionAt(widget, orientation, Orientation.AllOrientations)

    • setLineHeight

      public abstract void setLineHeight(WLength height)
      Sets the CSS line height for contained text.

    • getLineHeight

      public abstract WLength getLineHeight()
      Returns the CSS line height for contained text.

      sa setLineHeight()

    • setFloatSide

      public abstract void setFloatSide(Side s)
      Specifies a CSS float side.

      This only applies to widgets with a PositionScheme.Static getPositionScheme().

      This lets the widget float to one of the sides of the parent widget, at the current line. A typical use is to position images within text. Valid values for Side Side.Left, or Side.Right.

      This applies to CSS-based layout.

    • getFloatSide

      public abstract Side getFloatSide()
      Returns the CSS float side.

      See Also:

    • setClearSides

      public abstract void setClearSides(EnumSet<Side> sides)
      Sets the sides that should be cleared of floats.

      This pushes the widget down until it is not surrounded by floats at the sides (which may be a combination of Side.Left and Side.Right).

      This applies to CSS-based layout.

      See Also:

    • setClearSides

      public final void setClearSides(Side side, Side... sides)
      Sets the sides that should be cleared of floats.

      Calls setClearSides(EnumSet.of(side, sides))

    • getClearSides

      public abstract EnumSet<Side> getClearSides()
      Returns the sides that should remain empty.

      See Also:

    • setMargin

      public abstract void setMargin(WLength margin, EnumSet<Side> sides)
      Sets CSS margins around the widget.

      Setting margin has the effect of adding a distance between the widget and surrounding widgets. The default margin (with an automatic length) is zero.

      Use any combination of Side.Left, Side.Right, Side.Bottom, or Side.Top.

      This applies to CSS-based layout.

      See Also:

    • setMargin

      public final void setMargin(WLength margin, Side side, Side... sides)
      Sets CSS margins around the widget.

      Calls setMargin(margin, EnumSet.of(side, sides))

    • setMargin

      public final void setMargin(WLength margin)
      Sets CSS margins around the widget.

      Calls setMargin(margin, Side.AllSides)

    • setMargin

      public void setMargin(int pixels, EnumSet<Side> sides)
      Sets CSS margins around the widget.

      This is a convenience method for setting margins in pixel units.

      See Also:

    • setMargin

      public final void setMargin(int pixels, Side side, Side... sides)
      Sets CSS margins around the widget.

      Calls setMargin(pixels, EnumSet.of(side, sides))

    • setMargin

      public final void setMargin(int pixels)
      Sets CSS margins around the widget.

      Calls setMargin(pixels, Side.AllSides)

    • getMargin

      public abstract WLength getMargin(Side side)
      Returns a CSS margin set.

      This applies to CSS-based layout.

      See Also:

    • setHiddenKeepsGeometry

      public abstract void setHiddenKeepsGeometry(boolean enabled)
      Sets whether the widget keeps its geometry when hidden.

      Normally, a widget that is hidden will no longer occupy space, causing a reflow of sibling widgets. Using this method you may change this behavior to keep an (open) space when hidden.

      Note: Currently you can only set this before initial rendering.

      See Also:

    • isHiddenKeepsGeometry

      public abstract boolean isHiddenKeepsGeometry()
      Returns whether the widget keeps its geometry when hidden.

      See Also:

    • setHidden

      public abstract void setHidden(boolean hidden, WAnimation animation)
      Hides or shows the widget.

      Hides or show the widget (including all its descendant widgets). When setting hidden = false, this widget and all descendant widgets that are not hidden will be shown. A widget is only visible if it and all its ancestors in the widget tree are visible, which may be checked using isVisible().

    • setHidden

      public final void setHidden(boolean hidden)
      Hides or shows the widget.

      Calls setHidden(hidden, new WAnimation())

    • isHidden

      public abstract boolean isHidden()
      Returns whether the widget is set hidden.

      A widget that is not hidden may still be not visible when one of its ancestor widgets is hidden. Use isVisible() to check the visibility of a widget.

      See Also:

    • isVisible

      public abstract boolean isVisible()
      Returns whether the widget is visible.

      A widget is visible if it is not hidden, and none of its ancestors are hidden. This method returns the true visibility, while isHidden() returns whether a widget has been explicitly hidden.

      Note that a widget may be at the same time not hidden, and not visible, in case one of its ancestors was hidden.

      See Also:

    • setDisabled

      public abstract void setDisabled(boolean disabled)
      Sets whether the widget is disabled.

      The widget can be set to being disabled, or enabled. This state will also be propagated to all its descendants. Those descendants will only be "visually" made disabled, their actual isDisabled() state will remain unaltered. All descendants will be assigned the disabled styleclass, which is dependent on the used Theme.

      The isDisabled() check will thus only return true in case setDisabled(true) has been called on the widget before. If the anscestor of a widget has been marked setDisabled(true), the widget's isDisabled() state will remain false.

      To check if a widget has been passively disabled, by one of its anscestors, use isEnabled().

      Typically, a disabled form widget will not allow changing the value, and disabled widgets will not react to mouse click events.

      See Also:

    • isDisabled

      public abstract boolean isDisabled()
      Returns whether the widget is set disabled.

      This method will return true if, and only if, it has been marked setDisabled(true) explicitly. It can still inherit the disabled state from one of its anscestors.

      See Also:

    • isEnabled

      public abstract boolean isEnabled()
      Returns whether the widget is enabled.

      A widget is enabled if it is not disabled, and none of its ancestors are disabled. This method returns whether the widget is rendered as enabled, while isDisabled() returns whether a widget has been explicitly disabled.

      Note that a widget may be at the same time not enabled, and not disabled, in case one of its ancestors was disabled.

      See Also:

    • setPopup

      public abstract void setPopup(boolean popup)
      Lets the widget overlay over other sibling widgets.

      A widget that isPopup() will be rendered on top of any other sibling widget contained within the same parent (including other popup widgets previously added to the container).

      This will only have an effect when the widgetis either PositionScheme.Absolute or PositionScheme.Fixed getPositionScheme().

      This applies to CSS-based layout, and configures the z-index property.

    • isPopup

      public abstract boolean isPopup()
      Returns whether the widget is overlayed.

      This applies to CSS-based layout.

      See Also:

    • setInline

      public abstract void setInline(boolean inlined)
      Sets whether the widget is displayed inline or as a block.

      This option changes whether this widget must be rendered in line with sibling widgets wrapping at the right edge of the parent container (like text), or whether this widget must be rendered as a rectangular block that stacks vertically with sibling widgets (unless a CSS float property is applied). Depending on the widget type, the default value is inline (such as for example for WText, or WPushButton), or block (such as for example for a WContainerWidget).

      This applies to CSS-based layout.

    • isInline

      public abstract boolean isInline()
      Returns whether the widget is displayed inline or as block.

      See Also:

    • setDecorationStyle

      public abstract void setDecorationStyle(WCssDecorationStyle style)
      Sets a CSS decoration style.

      This copies the style over its current getDecorationStyle()

    • getDecorationStyle

      public abstract WCssDecorationStyle getDecorationStyle()
      Returns the decoration style of this widget.

      This groups all decorative aspects of the widget, which do not affect the widget layout (except for the border properties which may behave like extra margin around the widget).

      When a decoration style has not been previously set, it returns a default decoration style object.

      See Also:

    • setStyleClass

      public abstract void setStyleClass(String styleClass)
      Sets (one or more) CSS style classes.

      You may set one or more space separated style classes. CSS style class works in conjunction with style sheet, and provides a flexible way to provide many widgets the same markup.

      Setting an empty string removes the style class(es).

      See Also:

    • getStyleClass

      public abstract String getStyleClass()
      Returns the CSS style class.

      See Also:

    • addStyleClass

      public abstract void addStyleClass(String styleClass, boolean force)
      Adds a CSS style class.

      When force = true, a JavaScript call will be used to add the style class to the DOM element (if JavaScript is available). This may be necessary when client-side JavaScript manipulates the same style class.

      The styleClass should be a single class (although multiple classes will work for the common case that the additional style classes are all not yet present on the element.

    • addStyleClass

      public final void addStyleClass(String styleClass)
      Adds a CSS style class.

      Calls addStyleClass(styleClass, false)

    • removeStyleClass

      public abstract void removeStyleClass(String styleClass, boolean force)
      Removes a CSS style class.

      When force = true, a JavaScript call will be used to remove the style class from the DOM element (if JavaScript is available). This may be necessary when client-side JavaScript manipulates the same style class.

      The styleClass should be a single class

    • removeStyleClass

      public final void removeStyleClass(String styleClass)
      Removes a CSS style class.

      Calls removeStyleClass(styleClass, false)

    • toggleStyleClass

      public void toggleStyleClass(String styleClass, boolean add, boolean force)
      Toggles a CSS style class.

    • toggleStyleClass

      public final void toggleStyleClass(String styleClass, boolean add)
      Toggles a CSS style class.

      Calls toggleStyleClass(styleClass, add, false)

    • hasStyleClass

      public abstract boolean hasStyleClass(String styleClass)
      Returns whether the widget has a style class.

    • setVerticalAlignment

      public abstract void setVerticalAlignment(AlignmentFlag alignment, WLength length)
      Sets the vertical alignment.

      This only applies to inline widgets, and determines how to position itself on the current line, with respect to sibling inline widgets.

      This applies to CSS-based layout.

    • setVerticalAlignment

      public final void setVerticalAlignment(AlignmentFlag alignment)
      Sets the vertical alignment.

      Calls setVerticalAlignment(alignment, WLength.Auto)

    • getVerticalAlignment

      public abstract AlignmentFlag getVerticalAlignment()
      Returns the vertical alignment.

      This applies to CSS-based layout.

      See Also:

    • getVerticalAlignmentLength

      public abstract WLength getVerticalAlignmentLength()
      Returns the fixed vertical alignment that was set.

      This applies to CSS-based layout.

      See Also:

    • setToolTip

      public abstract void setToolTip(CharSequence text, TextFormat textFormat)
      Sets a tooltip.

      The tooltip is displayed when the cursor hovers over the widget.

      When textFormat is TextFormat.XHTML, the tooltip may contain any valid XHTML snippet. The tooltip will then be rendered using JavaScript.

      Note: This will set deferred tooltip to false.

    • setToolTip

      public final void setToolTip(CharSequence text)
      Sets a tooltip.

      Calls setToolTip(text, TextFormat.Plain)

    • getToolTip

      public abstract WString getToolTip()
      Returns the tooltip.

    • setDeferredToolTip

      public abstract void setDeferredToolTip(boolean enable, TextFormat textFormat)
      Enable deferred tooltip.

      You may override getToolTip() to read data only when the user hovers over the widget.

      When textFormat is TextFormat.XHTML, the tooltip may contain any valid XHTML snippet. The tooltip will then be rendered using JavaScript.

      Note: To change existing toolTip call setDeferredToolTip() again.

      See Also:

    • setDeferredToolTip

      public final void setDeferredToolTip(boolean enable)
      Enable deferred tooltip.

      Calls setDeferredToolTip(enable, TextFormat.Plain)

    • refresh

      public void refresh()
      Refresh the widget.

      The refresh method is invoked when the locale is changed using WApplication#setLocale() or when the user hit the refresh button.

      The widget must actualize its contents in response.

      Note: This does not rerender the widget! Calling refresh() usually does not have any effect (unless you've reimplemented refresh() to attach to it an effect).

    • getJsRef

      public String getJsRef()
      Returns a JavaScript expression to the corresponding DOM node.

      You may want to use this in conjunction with JSlot or doJavaScript() in custom JavaScript code.

      See Also:

    • setAttributeValue

      public abstract void setAttributeValue(String name, String value)
      Sets an attribute value.

      Sets the value for an HTML attribute.

      This is only useful for HTML features that are not supported directly in JWt (and beware that browsers have non-consistent support for many more exotic HTML features).

      See Also:

    • getAttributeValue

      public abstract String getAttributeValue(String name)
      Returns an attribute value.

      See Also:

    • setJavaScriptMember

      public abstract void setJavaScriptMember(String name, String value)
      Sets a JavaScript member.

      This binds a JavaScript member, which is set as a JavaScript property to the DOM object that implements this widget. The value may be any JavaScript expression, including a function.

      Members that start with "wt" are reserved for internal use. You may define a member "wtResize(self, width, height)" method if your widget needs active layout management. If defined, this method will be used by layout managers and when doing resize() to set the size of the widget, instead of setting the CSS width and height properties.

    • getJavaScriptMember

      public abstract String getJavaScriptMember(String name)
      Returns the value of a JavaScript member.

      See Also:

    • callJavaScriptMember

      public abstract void callJavaScriptMember(String name, String args)
      Calls a JavaScript member.

      This calls a JavaScript member.

      See Also:

    • tr

      public static WString tr(String key)
      Short hand for WString#tr()

      Creates a localized string with the given key.

    • load

      public abstract void load()
      Loads content just before the widget is used.

      This function is called when a widget is inserted in the widget hierarchy. Widgets that get inserted in the widget hierarchy will be rendered. Visible widgets are rendered immediately, and invisible widgets in the back-ground (or not for a plain HTML session). This method is called when the widget is directly or indirectly inserted into the widget tree.

      The default implementation simply propagates the load signal to its children. You may want to override this method to delay loading of resource-intensive contents.

      During the life-time of a widget, this method may be called multiple times, so you should make sure that you do a deferred initialization only once.

    • isLoaded

      public abstract boolean isLoaded()
      Returns whether this widget has been loaded.

      See Also:

    • setCanReceiveFocus

      public abstract void setCanReceiveFocus(boolean enabled)
      Sets whether the widget can receive focus.

      By default, only form widgets (descendants of WFormWidget), anchors (WAnchor) and buttons (WPushButton) can receive focus.

      Any other widget can be configured to receive focus however.

    • isCanReceiveFocus

      public abstract boolean isCanReceiveFocus()
      Returns whether the widget can receive focus.

      See Also:

    • setFocus

      public void setFocus()
      Sets focus.

      This only has an effect for a widget which can receive focus, and is equivalent to setFocus(true).

      See Also:

    • setFocus

      public abstract void setFocus(boolean focus)
      Sets focus.

      When using focus = false, you can undo a previous setFocus() call.

    • isSetFirstFocus

      public abstract boolean isSetFirstFocus()
      Set focus on the widget's first descendant.

      Set focus on the widget itself, or on a first descendant which can receive focus.

      Returns whether focus could be set.

    • hasFocus

      public abstract boolean hasFocus()
      Returns whether the widget currently has the focus.

    • setTabIndex

      public abstract void setTabIndex(int index)
      Sets the tab index.

      For widgets that receive focus (isCanReceiveFocus()), focus is passed on to the next widget in the tabbing chain based on their tab index. When the user navigates through form widgets using the keyboard, widgets receive focus starting from the element with the lowest tab index to elements with the highest tab index.

      Widgets with a same tab index will receive focus in the same order as they are inserted in the widget tree.

      The default tab index is 0 (for a widget that can receive focus).

    • getTabIndex

      public abstract int getTabIndex()
      Returns the tab index.

      See Also:

    • acceptDrops

      public void acceptDrops(String mimeType, String hoverStyleClass)
      Sets a mime type to be accepted for dropping.

      You may specify a style class that is applied to the widget when the specified mimetype hovers on top of it.

      See Also:

    • acceptDrops

      public final void acceptDrops(String mimeType)
      Sets a mime type to be accepted for dropping.

      Calls acceptDrops(mimeType, "")

    • stopAcceptDrops

      public void stopAcceptDrops(String mimeType)
      Indicates that a mime type is no longer accepted for dropping.

      See Also:

    • setId

      public abstract void setId(String id)
      Sets the CSS Id.

      Sets a custom Id. Note that the Id must be unique across the whole widget tree, can only be set right after construction and cannot be changed. This is mostly useful for in tests using a test plan that manipulates DOM elements by Id.

      By default, auto-generated id's are used.

      Note: An id must start with a letter ([A-Za-z]), followed by one or more letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").

      Warning: We recommend that you leave the id of a widget unchanged. JWt uses the id to identify widgets in the JavaScript it generates, and this can often leads to bugs. If you do change the id, only change the id right after widget construction. However, usually there's a more preferable alternative, like setting the object name (WObject#setObjectName()), or adding style classes (addStyleClass()).

      See Also:

    • find

      public abstract WWidget find(String name)
      Finds a descendent widget by name.

      See Also:

    • findById

      public abstract WWidget findById(String id)
      Finds a descendent widget by id.

    • htmlText

      public void htmlText(Writer out)
      Streams the (X)HTML representation.

      Streams the widget as CharEncoding::UTF8-encoded (HTML-compatible) XHTML.

      This may be useful as a debugging tool for the web-savvy, or in other rare situations. Usually, you will not deal directly with HTML, and calling this method on a widget that is rendered may interfere with the library keeping track of changes to the widget.

    • setSelectable

      public abstract void setSelectable(boolean selectable)
      Sets as selectable.

      When a widget is made unselectable, a selection of text (or images) will not be visible (but may still be possible).

      By default, the widget inherits this property from its parent, and this property propagates to all children. The top level container (WApplication.getRoot()) selectable by default.

    • doJavaScript

      public abstract void doJavaScript(String js)
      Executes the given JavaScript statements when the widget is rendered or updated.

      Calling WApplication#doJavaScript() with JavaScript code that refers to a widget using getJsRef(), that is still to be rendered may cause JavaScript errors because the corresponding DOM node does not exist. This happens for example when a widget is created, but not yet inserted in the widget tree.

      This method guarantees that the JavaScript code is only run when the corresponding DOM node (using getJsRef()) resolves to a valid DOM object.

      See Also:

    • isRendered

      public boolean isRendered()
      Returns whether the widget is rendered.

      See Also:

    • createJavaScript

      public String createJavaScript(StringBuilder js, String insertJS)

    • hide

      public void hide()
      Hides the widget.

      See Also:

    • animateHide

      public void animateHide(WAnimation animation)
      Hides the widget using an animation.

      To hide the widget, the animation is replayed in reverse.

      See Also:

    • show

      public void show()
      Shows the widget.

      See Also:

    • animateShow

      public void animateShow(WAnimation animation)
      Shows the widget using an animation.

      See Also:

    • enable

      public void enable()
      Enables the widget.

      This calls setDisabled().

    • disable

      public void disable()
      Disable thes widget.

      This calls setDisabled().

    • isLayoutSizeAware

      public boolean isLayoutSizeAware()
      Returns whether the widget is layout size aware.

      See Also:

    • isScrollVisibilityEnabled

      public abstract boolean isScrollVisibilityEnabled()
      Returns whether scroll visibility detection is enabled for this widget.

      See Also:

    • setScrollVisibilityEnabled

      public abstract void setScrollVisibilityEnabled(boolean enabled)
      Sets whether scroll visibility detection is enabled for this widget.

      Disabled by default. When enabled, the client keeps track of whether this widget is currently visible inside of the browser window. A widget is "scroll visible" if it is currently visible according to isVisible(), and its position is inside of the browser window, with an extra margin determined by getScrollVisibilityMargin().

      If scroll visibility changes, the scrollVisibilityChanged() signal is fired, and isScrollVisible() is updated.

      This feature can be useful to implement infinite scroll, where a sentinel widget placed at the bottom of the page causes more content to be loaded when it becomes visible, see the scrollvisibility example.

      This feature can also be used to lazy load widgets when they become visible.

      Note: If the widget is "scroll visible" when scroll visibility detection is first enabled, the scrollVisibilityChanged() signal will be emitted. If it is outside of the browser's viewport when first enabled, the scrollVisibilityChanged() signal will not be emitted.

      Note: If scroll visibility is enabled, disabled, and then enabled again, isScrollVisible() may not be correctly updated, and scrollVisibilityChanged() may not be correctly emitted, because then JWt can't properly keep track of the state that the widget is in on the client side. This feature is not intended to be toggled on and off, but rather enabled once and disabled once after that.

    • getScrollVisibilityMargin

      public abstract int getScrollVisibilityMargin()
      Returns the margin around the viewport within which the widget is considered visible.

      See Also:

    • setScrollVisibilityMargin

      public abstract void setScrollVisibilityMargin(int margin)
      Sets the margin around the viewport within which the widget is considered visible.

      This causes the widget to be considered "scroll visible" before it is within the viewport. Setting this margin could be useful to trigger the loading of content before it is in view.

    • scrollVisibilityChanged

      public abstract Signal1<Boolean> scrollVisibilityChanged()
      Signal triggered when the scroll visibility of this widget changes.

      The boolean parameter indicates whether the widget is currently scroll visible.

      See Also:

    • isScrollVisible

      public abstract boolean isScrollVisible()
      Returns whether this widget is currently considered scroll visible.

      isScrollVisible() is initially false.

      See Also:

    • setThemeStyleEnabled

      public abstract void setThemeStyleEnabled(boolean enabled)
      Sets whether theme styling for a widget is enabled or disabled.

      By default all widgets are styled according to the chosen theme. Disabling the theme style could be useful to completely customize the style of the widget outside of the theme.

      This function does, however, not always completely remove every style class added by JWt, as some of those are needed in order for the widget to function correctly. Additionally, Bootstrap 5 makes some changes to the default style of some widgets in the browser, like with buttons. These changes are not removed by this function.

      Note: This should be changed after the construction but before the rendering of the widget or before the call to applyThemeStyles() (depending on what happens first).

    • isThemeStyleEnabled

      public abstract boolean isThemeStyleEnabled()
      Returns whether this widget is currently styled by the chosen theme.

      isThemeEnabled() is initially true.

      See Also:

    • scheduleThemeStyleApply

      public void scheduleThemeStyleApply(WTheme theme, WWidget child, int role)
      Schedules a theme style to be applied at the next render.

      This schedules a theme style to be applied at the end of the next rendering of the widget, or when the next applyThemeStyles() is called (depending on what happens first).

      See Also:

    • applyThemeStyles

      public void applyThemeStyles()
      Apply the theme style scheduled.

      This apllies the theme styles scheduled for the next render of this widget.

      Warning: setThemeStyleEnabled() should not be called after using this method.

      See Also:

    • isExposed

      public boolean isExposed(WWidget w)

    • addJSignal

      public void addJSignal(AbstractEventSignal signal)

    • getBaseZIndex

      public abstract int getBaseZIndex()

    • setLayoutSizeAware

      protected void setLayoutSizeAware(boolean aware)
      Sets the widget to be aware of its size set by a layout manager.

      When the widget is inserted in a layout manager, it will be resized to fit within the constraints imposed by the layout manager. By default, this done client-side only by setting the CSS height (and if needed, width) properties of the DOM element corresponding to the widget.

      A widget may define a JavaScript method, "wtResize(self, width, height)", to actively manage its client-side width and height, if it wants to react to these client-side size hints in a custom way (see setJavaScriptMember()).

      By setting sizeAware to true, the widget will propagate the width and height provided by the layout manager to the virtual layoutSizeChanged() method, so that you may for example change the size of contained children in a particular way (doing a custom, manual, layout).

      See Also:

    • layoutSizeChanged

      protected void layoutSizeChanged(int width, int height)
      Virtual method that indicates a size change.

      This method propagates the client-side width and height of the widget when the widget is contained by a layout manager and setLayoutSizeAware(true) was called.

      See Also:

    • dropEvent

      protected void dropEvent(WDropEvent event)
      Handles a drop event.

      Reimplement this method to handle a drop events for mime types you declared to accept using acceptDrops.

      The default implementation simply completes the drag and drop operation as if nothing happened.

      See Also:

    • enableAjax

      protected abstract void enableAjax()
      Progresses to an Ajax-enabled widget.

      This method is called when the progressive bootstrap method is used, and support for AJAX has been detected. The default behavior will upgrade the widget's event handling to use AJAX instead of full page reloads, and propagate the call to its children.

      You may want to reimplement this method if you want to make changes to widget when AJAX is enabled. You should always call the base implementation.

      See Also:

    • boxPadding

      protected int boxPadding(Orientation orientation)
      Returns the widget's built-in padding.

      This is used by the layout managers to correct for a built-in padding which interferes with setting a widget's width (or height) to 100%.

      A layout manager needs to set the width to 100% only for form widgets (WTextArea, WLineEdit, WComboBox, etc...). Therefore, only for those widgets this needs to return the padding (the default implementation returns 0).

      For form widgets, the padding depends on the specific browser/platform combination, unless an explicit padding is set for the widget.

      When setting an explicit padding for the widget using a style class, you will want to reimplement this method to return this padding in case you want to set the widget inside a layout manager.

      See Also:

    • boxBorder

      protected int boxBorder(Orientation orientation)
      Returns the widget's built-in border width.

      This is used by the layout managers to correct for a built-in border which interferes with setting a widget's width (or height) to 100%.

      A layout manager needs to set the width to 100% only for form widgets (WTextArea, WLineEdit, WComboBox, etc...). Therefore, only for those widgets this needs to return the border width (the default implementation returns 0).

      For form widgets, the border width depends on the specific browser/platform combination, unless an explicit border is set for the widget.

      When setting an explicit border for the widget using a style class, you will want to reimplement this method to return this border width, in case you want to set the widget inside a layout manager.

      See Also:

    • propagateSetEnabled

      protected abstract void propagateSetEnabled(boolean enabled)
      Propagates that a widget was enabled or disabled through children.

      When enabling or disabling a widget, you usually also want to disable contained children. This method is called by setDisabled() to propagate its state to all children.

      You may want to reimplement this method if they wish to render differently when a widget is disabled. The default implementation will propagate the signal to all children.

    • propagateSetVisible

      protected abstract void propagateSetVisible(boolean visible)

    • getDropTouch

      protected void getDropTouch(String sourceId, String mimeType, WTouchEvent event)

    • scheduleRender

      protected void scheduleRender(EnumSet<eu.webtoolkit.jwt.RepaintFlag> flags)
      Schedules rerendering of the widget.

      This schedules a rendering phase after all events have been processed. This method is used internally whenever a property of a widget has been changed. But you may want to use this if you are deferring actual changes to a widget in response to an event, and instead postpone this until all events have been received.

      See Also:

    • scheduleRender

      protected final void scheduleRender(eu.webtoolkit.jwt.RepaintFlag flag, eu.webtoolkit.jwt.RepaintFlag... flags)
      Schedules rerendering of the widget.

      Calls scheduleRender(EnumSet.of(flag, flags))

    • scheduleRender

      protected final void scheduleRender()
      Schedules rerendering of the widget.

      Calls scheduleRender(EnumSet.noneOf(RepaintFlag.class))

    • render

      protected void render(EnumSet<RenderFlag> flags)
      Renders the widget.

      This function renders the widget (or an update for the widget), after this has been scheduled using scheduleRender().

      The default implementation will render the widget by serializing changes to JavaScript and HTML. You may want to reimplement this widget if you have been postponing some of the layout / rendering implementation until the latest moment possible. In that case you should make sure you call the base implementation however.

    • render

      protected final void render(RenderFlag flag, RenderFlag... flags)
      Renders the widget.

      Calls render(EnumSet.of(flag, flags))

    • needsRerender

      public boolean needsRerender()

    • addCssRule

      protected WCssTextRule addCssRule(String selector, String declarations, String ruleName)

    • addCssRule

      protected final WCssTextRule addCssRule(String selector, String declarations)

    • isGlobalWidget

      protected boolean isGlobalWidget()