Wt  4.10.4
Public Member Functions | List of all members
Wt::WContainerWidget Class Reference

A widget that holds and manages child widgets. More...

#include <Wt/WContainerWidget.h>

Inheritance diagram for Wt::WContainerWidget:
[legend]

Public Member Functions

 WContainerWidget ()
 Creates a container.
 
 ~WContainerWidget ()
 Destructor.
 
void setLayout (std::unique_ptr< WLayout > layout)
 Sets a layout manager for the container. More...
 
template<typename Layout >
Layout * setLayout (std::unique_ptr< Layout > layout)
 Sets a layout manager for the container, returning a raw pointer. More...
 
WLayoutlayout () const
 Returns the layout manager that was set for the container. More...
 
virtual void addWidget (std::unique_ptr< WWidget > widget)
 Adds a child widget to this container. More...
 
template<typename Widget >
Widget * addWidget (std::unique_ptr< Widget > widget)
 Adds a child widget to this container, returning a raw pointer. More...
 
template<typename Widget , typename ... Args>
Widget * addNew (Args &&...args)
 Creates a widget and adds it, returning a reference to it. More...
 
virtual void insertBefore (std::unique_ptr< WWidget > widget, WWidget *before)
 Inserts a child widget in this container, before another widget. More...
 
template<typename Widget >
Widget * insertBefore (std::unique_ptr< Widget > widget, WWidget *before)
 Inserts a child widget to this container, before another widget, returning a raw pointer. More...
 
virtual void insertWidget (int index, std::unique_ptr< WWidget > widget)
 Inserts a child widget in this container at given index. More...
 
template<typename Widget >
Widget * insertWidget (int index, std::unique_ptr< Widget > widget)
 Inserts a child widget to this container at given index, returning a raw pointer. More...
 
template<typename Widget , typename ... Args>
Widget * insertNew (int index, Args &&...args)
 Creates a widget and inserts it, returning a reference to it. More...
 
virtual std::unique_ptr< WWidgetremoveWidget (WWidget *widget) override
 Removes a child widget from this container. More...
 
virtual void clear ()
 Removes all widgets. More...
 
virtual int indexOf (WWidget *widget) const
 Returns the index of a widget.
 
virtual WWidgetwidget (int index) const
 Returns the widget at index
 
virtual int count () const
 Returns the number of widgets in this container.
 
void setContentAlignment (WFlags< AlignmentFlag > contentAlignment)
 Specifies how child widgets must be aligned within the container. More...
 
void setPadding (const WLength &padding, WFlags< Side > sides=AllSides)
 Sets padding inside the widget. More...
 
WLength padding (Side side) const
 Returns the padding set for the widget. More...
 
WFlags< AlignmentFlagcontentAlignment () const
 Returns the alignment of children. More...
 
void setOverflow (Overflow overflow, WFlags< Orientation > orientation=(Orientation::Horizontal|Orientation::Vertical))
 Sets how overflow of contained children must be handled.
 
void setList (bool list, bool ordered=false)
 Renders the container as an HTML list. More...
 
bool isList () const
 Returns if this container is rendered as a List. More...
 
bool isUnorderedList () const
 Returns if this container is rendered as an Unordered List. More...
 
bool isOrderedList () const
 Returns if this container is rendered as an Ordered List. More...
 
EventSignal< WScrollEvent > & scrolled ()
 Event signal emitted when scrolling in the widget. More...
 
int scrollTop () const
 return the number of pixels the container is scrolled horizontally More...
 
int scrollLeft () const
 return the number of pixels the container is scrolled vertically More...
 
virtual std::unique_ptr< WWidgetremoveWidget (WWidget *widget)
 Removes a child widget.
 
template<typename Widget >
std::unique_ptr< Widget > removeWidget (Widget *widget)
 Removes a child widget. More...
 
- Public Member Functions inherited from Wt::WInteractWidget
 WInteractWidget ()
 Create an InteractWidget.
 
EventSignal< WKeyEvent > & keyWentDown ()
 Event signal emitted when a keyboard key is pushed down. More...
 
EventSignal< WKeyEvent > & keyPressed ()
 Event signal emitted when a "character" was entered. More...
 
EventSignal< WKeyEvent > & keyWentUp ()
 Event signal emitted when a keyboard key is released. More...
 
EventSignalenterPressed ()
 Event signal emitted when enter was pressed. More...
 
EventSignalescapePressed ()
 Event signal emitted when escape was pressed. More...
 
EventSignal< WMouseEvent > & clicked ()
 Event signal emitted when the primary mouse button was clicked on this widget. More...
 
EventSignal< WMouseEvent > & doubleClicked ()
 Event signal emitted when the primary mouse button was double clicked on this widget. More...
 
EventSignal< WMouseEvent > & mouseWentDown ()
 Event signal emitted when a mouse button was pushed down on this widget. More...
 
EventSignal< WMouseEvent > & mouseWentUp ()
 Event signal emitted when a mouse button was released on this widget. More...
 
EventSignal< WMouseEvent > & mouseWentOut ()
 Event signal emitted when the mouse went out of this widget. More...
 
EventSignal< WMouseEvent > & mouseWentOver ()
 Event signal emitted when the mouse entered this widget. More...
 
EventSignal< WMouseEvent > & mouseMoved ()
 Event signal emitted when the mouse moved over this widget. More...
 
EventSignal< WMouseEvent > & mouseDragged ()
 Event signal emitted when the mouse is dragged over this widget. More...
 
EventSignal< WMouseEvent > & mouseWheel ()
 Event signal emitted when the mouse scroll wheel was used. More...
 
EventSignal< WTouchEvent > & touchStarted ()
 Event signal emitted when a finger is placed on the screen. More...
 
EventSignal< WTouchEvent > & touchEnded ()
 Event signal emitted when a finger is removed from the screen. More...
 
EventSignal< WTouchEvent > & touchMoved ()
 Event signal emitted when a finger, which is already placed on the screen, is moved across the screen. More...
 
EventSignal< WGestureEvent > & gestureStarted ()
 Event signal emitted when a gesture is started. More...
 
EventSignal< WGestureEvent > & gestureChanged ()
 Event signal emitted when a gesture is changed. More...
 
EventSignal< WGestureEvent > & gestureEnded ()
 Event signal emitted when a gesture is ended. More...
 
void setDraggable (const std::string &mimeType, WWidget *dragWidget=nullptr, bool isDragWidgetOnly=false, WObject *sourceWidget=nullptr)
 Configure dragging for drag and drop. More...
 
void unsetDraggable ()
 Disable drag & drop for this widget. More...
 
void setMouseOverDelay (int delay)
 Sets a delay for the mouse over event. More...
 
int mouseOverDelay () const
 Returns the mouse over signal delay. More...
 
virtual void setPopup (bool popup) override
 Lets the widget overlay over other sibling widgets. More...
 
virtual void load () override
 Loads content just before the widget is used. More...
 
virtual bool isEnabled () const override
 Returns whether the widget is enabled. More...
 
- Public Member Functions inherited from Wt::WWebWidget
 WWebWidget ()
 Construct a WebWidget.
 
virtual std::vector< WWidget * > children () const override
 Returns child widgets. More...
 
SignalchildrenChanged ()
 Signal emitted when children have been added or removed. More...
 
virtual void setPositionScheme (PositionScheme scheme) override
 Sets the CSS position scheme. More...
 
virtual PositionScheme positionScheme () const override
 Returns the CSS position scheme. More...
 
virtual void setOffsets (const WLength &offset, WFlags< Side > sides=AllSides) override
 Sets CSS offsets for a non-statically positioned widget. More...
 
virtual WLength offset (Side s) const override
 Returns a CSS offset. More...
 
virtual void resize (const WLength &width, const WLength &height) override
 Resizes the widget. More...
 
virtual WLength width () const override
 Returns the width. More...
 
virtual WLength height () const override
 Returns the height. More...
 
virtual void setMinimumSize (const WLength &width, const WLength &height) override
 Sets a minimum size. More...
 
virtual WLength minimumWidth () const override
 Returns the minimum width. More...
 
virtual WLength minimumHeight () const override
 Returns the minimum height. More...
 
virtual void setMaximumSize (const WLength &width, const WLength &height) override
 Sets a maximum size. More...
 
virtual WLength maximumWidth () const override
 Returns the maximum width. More...
 
virtual WLength maximumHeight () const override
 Returns the maximum height. More...
 
virtual void setLineHeight (const WLength &height) override
 Sets the CSS line height for contained text.
 
virtual WLength lineHeight () const override
 Returns the CSS line height for contained text. More...
 
virtual void setFloatSide (Side s) override
 Specifies a CSS float side. More...
 
virtual Side floatSide () const override
 Returns the CSS float side. More...
 
virtual void setClearSides (WFlags< Side > sides) override
 Sets the sides that should be cleared of floats. More...
 
virtual WFlags< SideclearSides () const override
 Returns the sides that should remain empty. More...
 
virtual void setMargin (const WLength &margin, WFlags< Side > sides=AllSides) override
 Sets CSS margins around the widget. More...
 
virtual WLength margin (Side side) const override
 Returns a CSS margin set. More...
 
virtual void setHiddenKeepsGeometry (bool enabled) override
 Sets whether the widget keeps its geometry when hidden. More...
 
virtual bool hiddenKeepsGeometry () const override
 Returns whether the widget keeps its geometry when hidden. More...
 
virtual void setHidden (bool hidden, const WAnimation &animation=WAnimation()) override
 Hides or shows the widget. More...
 
virtual bool isHidden () const override
 Returns whether the widget is set hidden. More...
 
virtual bool isVisible () const override
 Returns whether the widget is visible. More...
 
virtual void setDisabled (bool disabled) override
 Sets whether the widget is disabled. More...
 
virtual bool isDisabled () const override
 Returns whether the widget is set disabled. More...
 
virtual bool isPopup () const override
 Returns whether the widget is overlayed. More...
 
virtual void setInline (bool isInline) override
 Sets whether the widget is displayed inline or as a block. More...
 
virtual bool isInline () const override
 Returns whether the widget is displayed inline or as block. More...
 
virtual void setDecorationStyle (const WCssDecorationStyle &style) override
 Sets a CSS decoration style. More...
 
virtual WCssDecorationStyledecorationStyle () override
 Returns the decoration style of this widget. More...
 
virtual void setStyleClass (const WString &styleClass) override
 Sets (one or more) CSS style classes. More...
 
virtual WString styleClass () const override
 Returns the CSS style class. More...
 
virtual void addStyleClass (const WString &styleClass, bool force=false) override
 Adds a CSS style class. More...
 
virtual void removeStyleClass (const WString &styleClass, bool force=false) override
 Removes a CSS style class. More...
 
virtual bool hasStyleClass (const WString &styleClass) const override
 Returns whether the widget has a style class.
 
virtual void setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength()) override
 Sets the vertical alignment. More...
 
virtual AlignmentFlag verticalAlignment () const override
 Returns the vertical alignment. More...
 
virtual WLength verticalAlignmentLength () const override
 Returns the fixed vertical alignment that was set. More...
 
virtual void setToolTip (const WString &text, TextFormat textFormat=TextFormat::Plain) override
 Sets a tooltip. More...
 
virtual void setDeferredToolTip (bool enable, TextFormat textFormat=TextFormat::Plain) override
 Enable deferred tooltip. More...
 
virtual WString toolTip () const override
 Returns the tooltip.
 
virtual void refresh () override
 Refresh the widget. More...
 
virtual void setAttributeValue (const std::string &name, const WString &value) override
 Sets an attribute value. More...
 
virtual WString attributeValue (const std::string &name) const override
 Returns an attribute value. More...
 
virtual void setJavaScriptMember (const std::string &name, const std::string &value) override
 Sets a JavaScript member. More...
 
virtual std::string javaScriptMember (const std::string &name) const override
 Returns the value of a JavaScript member. More...
 
virtual void callJavaScriptMember (const std::string &name, const std::string &args) override
 Calls a JavaScript member. More...
 
virtual bool loaded () const override
 Returns whether this widget has been loaded. More...
 
virtual void setId (const std::string &id) override
 Sets the CSS Id. More...
 
virtual WWidgetfind (const std::string &name) override
 Finds a descendent widget by name. More...
 
virtual WWidgetfindById (const std::string &id) override
 Finds a descendent widget by id.
 
virtual void setSelectable (bool selectable) override
 Sets as selectable. More...
 
virtual void doJavaScript (const std::string &javascript) override
 Executes the given JavaScript statements when the widget is rendered or updated. More...
 
virtual const std::string id () const override
 Returns the (unique) identifier for this object. More...
 
void setLoadLaterWhenInvisible (bool)
 Change the way the widget is loaded when invisible. More...
 
std::string htmlTagName () const
 returns the current html tag name More...
 
void setHtmlTagName (const std::string &tag)
 set the custom HTML tag name More...
 
virtual void setCanReceiveFocus (bool enabled) override
 Sets whether the widget can receive focus. More...
 
virtual bool canReceiveFocus () const override
 Returns whether the widget can receive focus. More...
 
virtual bool setFirstFocus () override
 Set focus on the widget's first descendant. More...
 
virtual void setFocus (bool focus) override
 Sets focus. More...
 
virtual bool hasFocus () const override
 Returns whether the widget currently has the focus.
 
virtual void setTabIndex (int index) override
 Sets the tab index. More...
 
virtual int tabIndex () const override
 Returns the tab index. More...
 
EventSignalblurred ()
 Signal emitted when the widget lost focus. More...
 
EventSignalfocussed ()
 Signal emitted when the widget recieved focus. More...
 
virtual bool scrollVisibilityEnabled () const final override
 Returns whether scroll visibility detection is enabled for this widget. More...
 
virtual void setScrollVisibilityEnabled (bool enabled) final override
 Sets whether scroll visibility detection is enabled for this widget. More...
 
virtual int scrollVisibilityMargin () const final override
 Returns the margin around the viewport within which the widget is considered visible. More...
 
virtual void setScrollVisibilityMargin (int margin) final override
 Sets the margin around the viewport within which the widget is considered visible. More...
 
virtual Signal< bool > & scrollVisibilityChanged () final override
 Signal triggered when the scroll visibility of this widget changes. More...
 
virtual bool isScrollVisible () const final override
 Returns whether this widget is currently considered scroll visible. More...
 
virtual void setThemeStyleEnabled (bool enabled) final override
 Sets whether theme styling for a widget is enabled or disabled. More...
 
virtual bool isThemeStyleEnabled () const final override
 Returns whether this widget is currently styled by the chosen theme. More...
 
virtual void setObjectName (const std::string &name) override
 Sets an object name. More...
 
void setFocus ()
 Sets focus. More...
 
virtual void setFocus (bool focus)=0
 Sets focus. More...
 
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor. More...
 
WWidgetparent () const
 Returns the parent widget.
 
template<typename Widget >
std::unique_ptr< Widget > removeWidget (Widget *widget)
 Removes a child widget. More...
 
std::unique_ptr< WWidgetremoveFromParent ()
 Removes the widget from its parent. More...
 
void setWidth (const WLength &width)
 Sets the width. More...
 
void setHeight (const WLength &height)
 Sets the height. More...
 
virtual void positionAt (const WWidget *widget, Orientation orientation=Orientation::Vertical)
 Positions a widget next to another widget. More...
 
virtual void toggleStyleClass (const WString &styleClass, bool add, bool force=false)
 Toggles a CSS style class.
 
std::string jsRef () const
 Returns a JavaScript expression to the corresponding DOM node. More...
 
void setFocus ()
 Sets focus. More...
 
virtual void acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString())
 Sets a mime type to be accepted for dropping. More...
 
virtual void stopAcceptDrops (const std::string &mimeType)
 Indicates that a mime type is no longer accepted for dropping. More...
 
virtual void htmlText (std::ostream &out)
 Streams the (X)HTML representation. More...
 
bool isRendered () const
 Returns whether the widget is rendered. More...
 
void hide ()
 Hides the widget. More...
 
void animateHide (const WAnimation &animation)
 Hides the widget using an animation. More...
 
void show ()
 Shows the widget. More...
 
void animateShow (const WAnimation &animation)
 Shows the widget using an animation. More...
 
void enable ()
 Enables the widget. More...
 
void disable ()
 Disable thes widget. More...
 
bool layoutSizeAware () const
 Returns whether the widget is layout size aware. More...
 
- Public Member Functions inherited from Wt::WObject
void addChild (std::unique_ptr< WObject > child)
 Add a child WObject whose lifetime is determined by this WObject.
 
template<typename Child >
Child * addChild (std::unique_ptr< Child > child)
 Add a child WObject, returning a raw pointer. More...
 
std::unique_ptr< WObjectremoveChild (WObject *child)
 Remove a child WObject, so its lifetime is no longer determined by this WObject.
 
template<typename Child >
std::unique_ptr< Child > removeChild (Child *child)
 Remove a child WObject, so its lifetime is no longer determined by this WObject. More...
 
virtual std::string objectName () const
 Returns the object name. More...
 
void resetLearnedSlots ()
 Resets learned stateless slot implementations. More...
 
template<class T >
void resetLearnedSlot (void(T::*method)())
 Resets a learned stateless slot implementation. More...
 
template<class T >
WStatelessSlot * implementStateless (void(T::*method)())
 Declares a slot to be stateless and learn client-side behaviour on first invocation. More...
 
template<class T >
WStatelessSlot * implementStateless (void(T::*method)(), void(T::*undoMethod)())
 Declares a slot to be stateless and learn client-side behaviour in advance. More...
 
void isNotStateless ()
 Marks the current function as not stateless. More...
 
template<class T >
WStatelessSlot * implementJavaScript (void(T::*method)(), const std::string &jsCode)
 Provides a JavaScript implementation for a method. More...
 
- Public Member Functions inherited from Wt::Core::observable
 observable () noexcept
 Default constructor.
 
virtual ~observable ()
 Destructor. More...
 
template<typename... Args, typename C >
auto bindSafe (void(C::*method)(Args...)) noexcept
 Protects a method call against object destruction. More...
 
template<typename... Args, typename C >
auto bindSafe (void(C::*method)(Args...) const) const noexcept
 Protects a const method call against object destruction. More...
 
template<typename Function >
auto bindSafe (const Function &function) noexcept
 Protects a function against object destruction. More...
 

Additional Inherited Members

- Public Types inherited from Wt::WObject
typedef void(WObject::* Method) ()
 Typedef for a WObject method without arguments.
 
- Static Public Member Functions inherited from Wt::WWebWidget
static std::string jsStringLiteral (const std::string &v, char delimiter='\'')
 Turn a CharEncoding::UTF8 encoded string into a JavaScript string literal. More...
 
- Static Public Member Functions inherited from Wt::WWidget
static WString tr (const char *key)
 Short hand for WString::tr() More...
 
- Protected Member Functions inherited from Wt::WInteractWidget
virtual void propagateSetEnabled (bool enabled) override
 Propagates that a widget was enabled or disabled through children. More...
 
- Protected Member Functions inherited from Wt::WWebWidget
virtual void enableAjax () override
 Progresses to an Ajax-enabled widget. More...
 
virtual WStatelessSlot * getStateless (Method method) override
 On-demand stateless slot implementation. More...
 
virtual void render (WFlags< RenderFlag > flags) override
 Renders the widget. More...
 
- Protected Member Functions inherited from Wt::WWidget
void setLayoutSizeAware (bool sizeAware)
 Sets the widget to be aware of its size set by a layout manager. More...
 
virtual void layoutSizeChanged (int width, int height)
 Virtual method that indicates a size change. More...
 
 WWidget ()
 Creates a widget.
 
virtual void dropEvent (WDropEvent dropEvent)
 Handles a drop event. More...
 
virtual int boxPadding (Orientation orientation) const
 Returns the widget's built-in padding. More...
 
virtual int boxBorder (Orientation orientation) const
 Returns the widget's built-in border width. More...
 
void scheduleRender (WFlags< RepaintFlag > flags=None)
 Schedules rerendering of the widget. More...
 

Detailed Description

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.
auto container1 = std::make_unique<Wt::WContainerWidget>();
container1->addWidget(std::make_unique<Wt::WText>("Some text"));
container1->addWidget(std::make_unique<Wt::WImage>("images/img.png"));
Wt::WContainerWidget *child3 = container1->addWidget(std::make_unique<Wt::WContainerWidget>());
// Example 2:
// Instantiate a container widget which uses a layout manager
auto container2 = std::make_unique<Wt::WContainerWidget>();
container2->resize(Wt::WLength::Auto, 600); // give the container a fixed height.
auto layout = std::make_unique<Wt::WVBoxLayout>();
layout->addWidget(std::make_unique<Wt::WText>("Some text"));
layout->addWidget(std::make_unique<Wt::WImage>("images/img.png"));
container2->setLayout(std::move(layout)); // set the layout to the container.
A widget that holds and manages child widgets.
Definition: WContainerWidget.h:135
WLayout * layout() const
Returns the layout manager that was set for the container.
Definition: WContainerWidget.h:191
virtual void addWidget(std::unique_ptr< WWidget > widget)
Adds a child widget to this container.
Definition: WContainerWidget.C:115
void addWidget(std::unique_ptr< WWidget > widget)
Adds the given widget to the layout.
Definition: WLayout.C:107
static WLength Auto
An 'auto' length.
Definition: WLength.h:65

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 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:

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

Member Function Documentation

◆ addNew()

template<typename Widget , typename ... Args>
Widget* Wt::WContainerWidget::addNew ( Args &&...  args)

Creates a widget and adds it, returning a reference to it.

This is a useful shorthand for adding a new widget to the container, and getting a reference to it, e.g.:

Wt::WPushButton *button = container->addNew<Wt::WPushButton>("Click me!");
// do something with button, including safely using it in a lambda function
A widget that represents a push button.
Definition: WPushButton.h:42

The implementation is equivalent to the following code:

std::unique_ptr<Widget> w{new Widget(std::forward<Args>(args)...)};
Widget *result = w.get();
addWidget(std::unique_ptr<WWidget>{std::move(w)});
return result;

There's an exception for global widgets, like WPopupWidget. In this case the implementation is equivalent to:

std::unique_ptr<Widget> w{new Widget(std::forward<Args>(args)...)};
Widget *result = w.get();
addChild(std::unique_ptr<WObject>(std::move(w)));
return result;
void addChild(std::unique_ptr< WObject > child)
Add a child WObject whose lifetime is determined by this WObject.
Definition: WObject.C:36

Since popup widgets (and similar widgets) are always and automatically placed in a global location in the widget tree, only their ownership is transferred.

◆ addWidget() [1/2]

template<typename Widget >
Widget* Wt::WContainerWidget::addWidget ( std::unique_ptr< Widget >  widget)

Adds a child widget to this container, returning a raw pointer.

This is implemented as:

Widget *result = widget.get();
addWidget(std::unique_ptr<WWidget>(std::move(widget)));
return result;
virtual WWidget * widget(int index) const
Returns the widget at index
Definition: WContainerWidget.C:235

This is a useful shorthand to add a widget and get a raw pointer to it, e.g.:

Wt::WPushButton *button = container->addWidget(std::make_unique<Wt::WPushButton>("Click me!"));
// do something with button, including safely using it in a lambda function

◆ addWidget() [2/2]

void Wt::WContainerWidget::addWidget ( std::unique_ptr< WWidget widget)
virtual

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()

Reimplemented in Wt::WStackedWidget.

◆ clear()

void Wt::WContainerWidget::clear ( )
virtual

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.

◆ contentAlignment()

WFlags<AlignmentFlag> Wt::WContainerWidget::contentAlignment ( ) const

Returns the alignment of children.

See also
setContentAlignment(WFlags<AlignmentFlag>)

◆ insertBefore() [1/2]

template<typename Widget >
Widget* Wt::WContainerWidget::insertBefore ( std::unique_ptr< Widget >  widget,
WWidget before 
)

Inserts a child widget to this container, before another widget, returning a raw pointer.

This is implemented as:

Widget *result = widget.get();
insertBefore(std::unique_ptr<WWidget>(std::move(widget)), before);
return result;
virtual void insertBefore(std::unique_ptr< WWidget > widget, WWidget *before)
Inserts a child widget in this container, before another widget.
Definition: WContainerWidget.C:120

◆ insertBefore() [2/2]

void Wt::WContainerWidget::insertBefore ( std::unique_ptr< WWidget widget,
WWidget before 
)
virtual

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()

See also
insertWidget(int index, WWidget *widget);

◆ insertNew()

template<typename Widget , typename ... Args>
Widget* Wt::WContainerWidget::insertNew ( int  index,
Args &&...  args 
)

Creates a widget and inserts it, returning a reference to it.

This is implemented as:

std::unique_ptr<Widget> w{new Widget(std::forward<Args>(args)...)};
Widget *result = w.get();
insertWidget(index, std::unique_ptr<WWidget>{std::move(w)});
return result;
virtual void insertWidget(int index, std::unique_ptr< WWidget > widget)
Inserts a child widget in this container at given index.
Definition: WContainerWidget.C:133

◆ insertWidget() [1/2]

template<typename Widget >
Widget* Wt::WContainerWidget::insertWidget ( int  index,
std::unique_ptr< Widget >  widget 
)

Inserts a child widget to this container at given index, returning a raw pointer.

This is implemented as:

Widget *result = widget.get();
insertWidget(index, std::unique_ptr<WWidget>(std::move(widget)));
return result;

◆ insertWidget() [2/2]

void Wt::WContainerWidget::insertWidget ( int  index,
std::unique_ptr< WWidget widget 
)
virtual

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()

See also
insertBefore(WWidget *widget, WWidget *before);

Reimplemented in Wt::WStackedWidget.

◆ isList()

bool Wt::WContainerWidget::isList ( ) const

Returns if this container is rendered as a List.

See also
setList(), isOrderedList(), isUnorderedList()

◆ isOrderedList()

bool Wt::WContainerWidget::isOrderedList ( ) const

Returns if this container is rendered as an Ordered List.

See also
setList(), isList(), isUnorderedList()

◆ isUnorderedList()

bool Wt::WContainerWidget::isUnorderedList ( ) const

Returns if this container is rendered as an Unordered List.

See also
setList(), isList(), isOrderedList()

◆ layout()

WLayout* Wt::WContainerWidget::layout ( ) const

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 *)

◆ padding()

WLength Wt::WContainerWidget::padding ( Side  side) const

Returns the padding set for the widget.

See also
setPadding(const WLength&, WFlags<Side>)

◆ removeWidget() [1/2]

template<typename Widget >
std::unique_ptr<Widget> Wt::WWidget::removeWidget ( typename Widget  )

Removes a child widget.

This is an overload that automatically casts the returned value to a unique_ptr<Widget> for convenience

This is implemented as:

return std::unique_ptr<Widget>(static_cast<Widget*>(removeWidget(static_cast<WWidget*>(widget)).release()));
virtual std::unique_ptr< WWidget > removeWidget(WWidget *widget)
Removes a child widget.
Definition: WWidget.C:48
WWidget()
Creates a widget.
Definition: WWidget.C:27

◆ removeWidget() [2/2]

std::unique_ptr< WWidget > Wt::WContainerWidget::removeWidget ( WWidget widget)
overridevirtual

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.

Reimplemented from Wt::WWidget.

Reimplemented in Wt::WStackedWidget.

◆ scrolled()

EventSignal< WScrollEvent > & Wt::WContainerWidget::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()

◆ scrollLeft()

int Wt::WContainerWidget::scrollLeft ( ) const

return the number of pixels the container is scrolled vertically

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

See also
setOverflow()
scrollTop();

◆ scrollTop()

int Wt::WContainerWidget::scrollTop ( ) const

return the number of pixels the container is scrolled horizontally

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

See also
setOverflow()
scrollLeft();

◆ setContentAlignment()

void Wt::WContainerWidget::setContentAlignment ( WFlags< AlignmentFlag contentAlignment)

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 (Wt::AlignmentFlag::Top | Wt::AlignmentFlag::Left).

◆ setLayout() [1/2]

template<typename Layout >
Layout* Wt::WContainerWidget::setLayout ( std::unique_ptr< Layout >  layout)

Sets a layout manager for the container, returning a raw pointer.

This is implemented as:

Layout *result = layout.get();
setLayout(std::unique_ptr<WLayout>(std::move(layout)));
return result;
void setLayout(std::unique_ptr< WLayout > layout)
Sets a layout manager for the container.
Definition: WContainerWidget.C:62

This is a useful shorthand that allows to create a layout and get a raw pointer to it in one line.

◆ setLayout() [2/2]

void Wt::WContainerWidget::setLayout ( std::unique_ptr< 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
layout()

◆ setList()

void Wt::WContainerWidget::setList ( bool  list,
bool  ordered = false 
)

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()

◆ setPadding()

void Wt::WContainerWidget::setPadding ( const WLength padding,
WFlags< Side sides = AllSides 
)

Sets padding inside the widget.

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