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Internal/Contributor docs for the Qt SDK. <b>Note:</b> These are NOT official API docs; those are found <a href='https://doc.qt.io/'>here</a>.
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Public Member Functions | List of all members
QHBoxLayout Class Reference

The QHBoxLayout class lines up widgets horizontally. More...

#include <qboxlayout.h>

+ Inheritance diagram for QHBoxLayout:
+ Collaboration diagram for QHBoxLayout:

Public Member Functions

 QHBoxLayout ()
 Constructs a new horizontal box.
 
 QHBoxLayout (QWidget *parent)
 Constructs a new top-level horizontal box with parent parent.
 
 ~QHBoxLayout ()
 Destroys this box layout.
 
- Public Member Functions inherited from QBoxLayout
 QBoxLayout (Direction, QWidget *parent=nullptr)
 Constructs a new QBoxLayout with direction dir and parent widget parent.
 
 ~QBoxLayout ()
 Destroys this box layout.
 
Direction direction () const
 Returns the direction of the box.
 
void setDirection (Direction)
 Sets the direction of this layout to direction.
 
void addSpacing (int size)
 Adds a non-stretchable space (a QSpacerItem) with size size to the end of this box layout.
 
void addStretch (int stretch=0)
 Adds a stretchable space (a QSpacerItem) with zero minimum size and stretch factor stretch to the end of this box layout.
 
void addSpacerItem (QSpacerItem *spacerItem)
 
void addWidget (QWidget *, int stretch=0, Qt::Alignment alignment=Qt::Alignment())
 Adds widget to the end of this box layout, with a stretch factor of stretch and alignment alignment.
 
void addLayout (QLayout *layout, int stretch=0)
 Adds layout to the end of the box, with serial stretch factor stretch.
 
void addStrut (int)
 Limits the perpendicular dimension of the box (e.g.
 
void addItem (QLayoutItem *) override
 \reimp
 
void insertSpacing (int index, int size)
 Inserts a non-stretchable space (a QSpacerItem) at position index, with size size.
 
void insertStretch (int index, int stretch=0)
 Inserts a stretchable space (a QSpacerItem) at position index, with zero minimum size and stretch factor stretch.
 
void insertSpacerItem (int index, QSpacerItem *spacerItem)
 
void insertWidget (int index, QWidget *widget, int stretch=0, Qt::Alignment alignment=Qt::Alignment())
 Inserts widget at position index, with stretch factor stretch and alignment alignment.
 
void insertLayout (int index, QLayout *layout, int stretch=0)
 Inserts layout at position index, with stretch factor stretch.
 
void insertItem (int index, QLayoutItem *)
 Inserts item into this box layout at position index.
 
int spacing () const override
 Reimplements QLayout::spacing().
 
void setSpacing (int spacing) override
 Reimplements QLayout::setSpacing().
 
bool setStretchFactor (QWidget *w, int stretch)
 Sets the stretch factor for widget to stretch and returns true if widget is found in this layout (not including child layouts); otherwise returns false.
 
bool setStretchFactor (QLayout *l, int stretch)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the stretch factor for the layout layout to stretch and returns true if layout is found in this layout (not including child layouts); otherwise returns false.
 
void setStretch (int index, int stretch)
 Sets the stretch factor at position index.
 
int stretch (int index) const
 Returns the stretch factor at position index.
 
QSize sizeHint () const override
 \reimp
 
QSize minimumSize () const override
 \reimp
 
QSize maximumSize () const override
 \reimp
 
bool hasHeightForWidth () const override
 \reimp
 
int heightForWidth (int) const override
 \reimp
 
int minimumHeightForWidth (int) const override
 \reimp
 
Qt::Orientations expandingDirections () const override
 \reimp
 
void invalidate () override
 Resets cached information.
 
QLayoutItem * itemAt (int) const override
 \reimp
 
QLayoutItem * takeAt (int) override
 \reimp
 
int count () const override
 \reimp
 
void setGeometry (const QRect &) override
 \reimp
 
- Public Member Functions inherited from QLayout
 QLayout (QWidget *parent=nullptr)
 Constructs a new top-level QLayout, with parent parent.
 
 ~QLayout ()
 
void setContentsMargins (int left, int top, int right, int bottom)
 
void setContentsMargins (const QMargins &margins)
 
void unsetContentsMargins ()
 
void getContentsMargins (int *left, int *top, int *right, int *bottom) const
 
QMargins contentsMargins () const
 
QRect contentsRect () const
 
bool setAlignment (QWidget *w, Qt::Alignment alignment)
 Sets the alignment for widget w to alignment and returns true if w is found in this layout (not including child layouts); otherwise returns false.
 
bool setAlignment (QLayout *l, Qt::Alignment alignment)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the alignment for the layout l to alignment and returns true if l is found in this layout (not including child layouts); otherwise returns false.
 
void setSizeConstraint (SizeConstraint)
 
SizeConstraint sizeConstraint () const
 
void setMenuBar (QWidget *w)
 Tells the geometry manager to place the menu bar widget at the top of parentWidget(), outside QWidget::contentsMargins().
 
QWidget * menuBar () const
 Returns the menu bar set for this layout, or \nullptr if no menu bar is set.
 
QWidget * parentWidget () const
 Returns the parent widget of this layout, or \nullptr if this layout is not installed on any widget.
 
void invalidate () override
 \reimp
 
QRect geometry () const override
 \reimp
 
bool activate ()
 Redoes the layout for parentWidget() if necessary.
 
void update ()
 Updates the layout for parentWidget().
 
void addWidget (QWidget *w)
 Adds widget w to this layout in a manner specific to the layout.
 
void removeWidget (QWidget *w)
 Removes the widget widget from the layout.
 
void removeItem (QLayoutItem *)
 Removes the layout item item from the layout.
 
Qt::Orientations expandingDirections () const override
 Returns whether this layout can make use of more space than sizeHint().
 
QSize minimumSize () const override
 Returns the minimum size of this layout.
 
QSize maximumSize () const override
 Returns the maximum size of this layout.
 
virtual int indexOf (const QWidget *) const
 Searches for widget widget in this layout (not including child layouts).
 
virtual int indexOf (const QLayoutItem *) const
 
bool isEmpty () const override
 \reimp
 
QSizePolicy::ControlTypes controlTypes () const override
 \reimp
 
virtual QLayoutItem * replaceWidget (QWidget *from, QWidget *to, Qt::FindChildOptions options=Qt::FindChildrenRecursively)
 
int totalMinimumHeightForWidth (int w) const
 
int totalHeightForWidth (int w) const
 
QSize totalMinimumSize () const
 
QSize totalMaximumSize () const
 
QSize totalSizeHint () const
 
QLayout * layout () override
 \reimp
 
void setEnabled (bool)
 Enables this layout if enable is true, otherwise disables it.
 
bool isEnabled () const
 Returns true if the layout is enabled; otherwise returns false.
 
void setAlignment (Qt::Alignment a)
 Sets the alignment of this item to alignment.
 
- Public Member Functions inherited from QObject
Q_INVOKABLE QObject (QObject *parent=nullptr)
 Constructs an object with parent object parent.
 
virtual ~QObject ()
 Destroys the object, deleting all its child objects.
 
virtual bool event (QEvent *event)
 This virtual function receives events to an object and should return true if the event e was recognized and processed.
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 Filters events if this object has been installed as an event filter for the watched object.
 
QString objectName () const
 
Q_WEAK_OVERLOAD void setObjectName (const QString &name)
 Sets the object's name to name.
 
void setObjectName (QAnyStringView name)
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
QBindable< QString > bindableObjectName ()
 
bool isWidgetType () const
 Returns true if the object is a widget; otherwise returns false.
 
bool isWindowType () const
 Returns true if the object is a window; otherwise returns false.
 
bool isQuickItemType () const
 Returns true if the object is a QQuickItem; otherwise returns false.
 
bool signalsBlocked () const noexcept
 Returns true if signals are blocked; otherwise returns false.
 
bool blockSignals (bool b) noexcept
 If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
 
QThread * thread () const
 Returns the thread in which the object lives.
 
bool moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
 Changes the thread affinity for this object and its children and returns true on success.
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
 
int startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
 
void killTimer (int id)
 Kills the timer with timer identifier, id.
 
void killTimer (Qt::TimerId id)
 
template<typename T >
T findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
 
template<typename T >
QList< T > findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
 
template<typename T >
T findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
template<typename T >
QList< T > findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
 
const QObjectList & children () const
 Returns a list of child objects.
 
void setParent (QObject *parent)
 Makes the object a child of parent.
 
void installEventFilter (QObject *filterObj)
 Installs an event filter filterObj on this object.
 
void removeEventFilter (QObject *obj)
 Removes an event filter object obj from this object.
 
QMetaObject::Connection connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
 
bool disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
 
bool disconnect (const QObject *receiver, const char *member=nullptr) const
 
void dumpObjectTree () const
 Dumps a tree of children to the debug output.
 
void dumpObjectInfo () const
 Dumps information about signal connections, etc.
 
bool setProperty (const char *name, const QVariant &value)
 Sets the value of the object's name property to value.
 
bool setProperty (const char *name, QVariant &&value)
 
QVariant property (const char *name) const
 Returns the value of the object's name property.
 
QList< QByteArray > dynamicPropertyNames () const
 
QBindingStorage * bindingStorage ()
 
const QBindingStorage * bindingStorage () const
 
QObject * parent () const
 Returns a pointer to the parent object.
 
bool inherits (const char *classname) const
 Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.
 
- Public Member Functions inherited from QLayoutItem
 QLayoutItem (Qt::Alignment alignment=Qt::Alignment())
 Constructs a layout item with an alignment.
 
virtual ~QLayoutItem ()
 Destroys the QLayoutItem.
 
virtual QWidget * widget () const
 If this item manages a QWidget, returns that widget.
 
virtual QSpacerItem * spacerItem ()
 If this item is a QSpacerItem, it is returned as a QSpacerItem; otherwise \nullptr is returned.
 
Qt::Alignment alignment () const
 Returns the alignment of this item.
 
void setAlignment (Qt::Alignment a)
 Sets the alignment of this item to alignment.
 

Additional Inherited Members

- Public Types inherited from QBoxLayout
enum  Direction {
  LeftToRight , RightToLeft , TopToBottom , BottomToTop ,
  Down = TopToBottom , Up = BottomToTop
}
 This type is used to determine the direction of a box layout. More...
 
- Public Types inherited from QLayout
enum  SizeConstraint {
  SetDefaultConstraint , SetNoConstraint , SetMinimumSize , SetFixedSize ,
  SetMaximumSize , SetMinAndMaxSize
}
 The possible values are: More...
 
- Public Slots inherited from QObject
void deleteLater ()
 \threadsafe
 
- Signals inherited from QObject
void destroyed (QObject *=nullptr)
 This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
 
void objectNameChanged (const QString &objectName, QPrivateSignal)
 This signal is emitted after the object's name has been changed.
 
- Static Public Member Functions inherited from QLayout
static QSize closestAcceptableSize (const QWidget *w, const QSize &s)
 Returns a size that satisfies all size constraints on widget, including heightForWidth() and that is as close as possible to size.
 
- Static Public Member Functions inherited from QObject
static QMetaObject::Connection connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
 \threadsafe
 
static QMetaObject::Connection connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
 
template<typename Func1 , typename Func2 >
static QMetaObject::Connection connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
 
static bool disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
 \threadsafe
 
static bool disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
 
static bool disconnect (const QMetaObject::Connection &)
 Disconnect a connection.
 
template<typename Func1 , typename Func2 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
 
template<typename Func1 >
static bool disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)
 
- Protected Member Functions inherited from QLayout
void widgetEvent (QEvent *)
 
void childEvent (QChildEvent *e) override
 \reimp
 
void addChildLayout (QLayout *l)
 This function is called from addLayout() or insertLayout() functions in subclasses to add layout childLayout as a sub-layout.
 
void addChildWidget (QWidget *w)
 This function is called from addWidget() functions in subclasses to add w as a managed widget of a layout.
 
bool adoptLayout (QLayout *layout)
 
QRect alignmentRect (const QRect &) const
 Returns the rectangle that should be covered when the geometry of this layout is set to r, provided that this layout supports setAlignment().
 
 QLayout (QLayoutPrivate &d, QLayout *, QWidget *)
 
- Protected Member Functions inherited from QObject
QObject * sender () const
 Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
 
int senderSignalIndex () const
 
int receivers (const char *signal) const
 Returns the number of receivers connected to the signal.
 
bool isSignalConnected (const QMetaMethod &signal) const
 
virtual void timerEvent (QTimerEvent *event)
 This event handler can be reimplemented in a subclass to receive timer events for the object.
 
virtual void customEvent (QEvent *event)
 This event handler can be reimplemented in a subclass to receive custom events.
 
virtual void connectNotify (const QMetaMethod &signal)
 
virtual void disconnectNotify (const QMetaMethod &signal)
 
 QObject (QObjectPrivate &dd, QObject *parent=nullptr)
 
- Protected Attributes inherited from QObject
QScopedPointer< QObjectData > d_ptr
 
- Protected Attributes inherited from QLayoutItem
Qt::Alignment align
 
- Properties inherited from QLayout
int spacing
 the spacing between widgets inside the layout
 
QMargins contentsMargins
 
SizeConstraint sizeConstraint
 the resize mode of the layout
 
- Properties inherited from QObject
QString objectName
 the name of this object
 
- Related Symbols inherited from QObject
 Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
 
 
 
 \macro Q_CLASSINFO(Name, Value)
 

Detailed Description

The QHBoxLayout class lines up widgets horizontally.

\inmodule QtWidgets

This class is used to construct horizontal box layout objects. See QBoxLayout for details.

The simplest use of the class is like this:

QPushButton *button2 = new QPushButton("Two");
QPushButton *button3 = new QPushButton("Three");
QPushButton *button4 = new QPushButton("Four");
QPushButton *button5 = new QPushButton("Five");

\codeline

layout->addWidget(button1);
layout->addWidget(button2);
layout->addWidget(button3);
layout->addWidget(button4);
layout->addWidget(button5);

First, we create the widgets we want to add to the layout. Then, we create the QHBoxLayout object, setting window as parent by passing it in the constructor; next we add the widgets to the layout. window will be the parent of the widgets that are added to the layout.

If you don't pass a parent window to the constructor, you can at a later point use QWidget::setLayout() to install the QHBoxLayout object onto window. At that point, the widgets in the layout are reparented to have window as their parent.

Horizontal box layout with five child widgets

See also
QVBoxLayout, QGridLayout, QStackedLayout, {Layout Management}, {Basic Layouts Example}

Definition at line 77 of file qboxlayout.h.

Constructor & Destructor Documentation

◆ QHBoxLayout() [1/2]

QHBoxLayout::QHBoxLayout ( )

Constructs a new horizontal box.

You must add it to another layout.

Definition at line 1236 of file qboxlayout.cpp.

◆ QHBoxLayout() [2/2]

QHBoxLayout::QHBoxLayout ( QWidget * parent)
explicit

Constructs a new top-level horizontal box with parent parent.

The layout is set directly as the top-level layout for parent. There can be only one top-level layout for a widget. It is returned by QWidget::layout().

See also
QWidget::setLayout()

Definition at line 1227 of file qboxlayout.cpp.

◆ ~QHBoxLayout()

QHBoxLayout::~QHBoxLayout ( )

Destroys this box layout.

The layout's widgets aren't destroyed.

Definition at line 1250 of file qboxlayout.cpp.

The documentation for this class was generated from the following files: