class QLayout

The QLayout class is the base class of geometry managers. More…

Inheritance diagram of PySide6.QtWidgets.QLayout

Inherited by: QStackedLayout, QGridLayout, QFormLayout, QBoxLayout, QVBoxLayout, QHBoxLayout

Synopsis

Properties

Methods

Virtual methods

Static functions

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description

This is an abstract base class inherited by the concrete classes QBoxLayout , QGridLayout , QFormLayout , and QStackedLayout .

For users of QLayout subclasses or of QMainWindow there is seldom any need to use the basic functions provided by QLayout , such as setSizeConstraint() or setMenuBar() . See Layout Management for more information.

To make your own layout manager, implement the functions addItem() , sizeHint() , setGeometry() , itemAt() and takeAt() . You should also implement minimumSize() to ensure your layout isn’t resized to zero size if there is too little space. To support children whose heights depend on their widths, implement hasHeightForWidth() and heightForWidth() . See the Flow Layout example for more information about implementing custom layout managers.

Geometry management stops when the layout manager is deleted.

See also

QLayoutItem Layout Management Basic Layouts Example Flow Layout Example

class SizeConstraint

The possible values are:

Constant

Description

QLayout.SetDefaultConstraint

The main widget’s minimum size is set to minimumSize() , unless the widget already has a minimum size.

QLayout.SetFixedSize

The main widget’s size is set to sizeHint() ; it cannot be resized at all.

QLayout.SetMinimumSize

The main widget’s minimum size is set to minimumSize() ; it cannot be smaller.

QLayout.SetMaximumSize

The main widget’s maximum size is set to maximumSize() ; it cannot be larger.

QLayout.SetMinAndMaxSize

The main widget’s minimum size is set to minimumSize() and its maximum size is set to maximumSize() .

QLayout.SetNoConstraint

The widget is not constrained.

See also

setSizeConstraint()

Note

Properties can be used directly when from __feature__ import true_property is used or via accessor functions otherwise.

property contentsMarginsᅟ: QMargins
Access functions:
property sizeConstraintᅟ: QLayout.SizeConstraint

This property holds the resize mode of the layout.

The default mode is SetDefaultConstraint .

Access functions:
property spacingᅟ: int

This property holds the spacing between widgets inside the layout.

If no value is explicitly set, the layout’s spacing is inherited from the parent layout, or from the style settings for the parent widget.

For QGridLayout and QFormLayout , it is possible to set different horizontal and vertical spacings using setHorizontalSpacing() and setVerticalSpacing() . In that case, spacing() returns -1.

Access functions:
__init__([parent=None])
Parameters:

parent – QWidget

Constructs a new top-level QLayout , 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 layout() .

If parent is None, then you must insert this layout into another layout, or set it as a widget’s layout using setLayout() .

See also

setLayout()

activate()
Return type:

bool

Redoes the layout for parentWidget() if necessary.

You should generally not need to call this because it is automatically called at the most appropriate times. It returns true if the layout was redone.

addChildLayout(l)
Parameters:

l – QLayout

This function is called from addLayout() or insertLayout() functions in subclasses to add layout childLayout as a sub-layout.

The only scenario in which you need to call it directly is if you implement a custom layout that supports nested layouts.

addChildWidget(w)
Parameters:

w – QWidget

This function is called from addWidget() functions in subclasses to add w as a managed widget of a layout.

If w is already managed by a layout, this function will produce a warning, and remove w from that layout. This function must therefore be called before adding w to the layout’s data structure.

abstract addItem(arg__1)
Parameters:

arg__1 – QLayoutItem

Implemented in subclasses to add an item. How it is added is specific to each subclass.

This function is not usually called in application code. To add a widget to a layout, use the addWidget() function; to add a child layout, use the addLayout() function provided by the relevant QLayout subclass.

Note

The ownership of item is transferred to the layout, and it’s the layout’s responsibility to delete it.

See also

addWidget() addLayout() addLayout()

addWidget(w)
Parameters:

w – QWidget

Adds widget w to this layout in a manner specific to the layout. This function uses addItem() .

adoptLayout(layout)
Parameters:

layout – QLayout

Return type:

bool

alignmentRect(arg__1)
Parameters:

arg__1 – QRect

Return type:

QRect

Returns the rectangle that should be covered when the geometry of this layout is set to r, provided that this layout supports setAlignment() .

The result is derived from sizeHint() and expandingDirections() . It is never larger than r.

static closestAcceptableSize(w, s)
Parameters:
Return type:

QSize

Returns a size that satisfies all size constraints on widget, including heightForWidth() and that is as close as possible to size.

contentsMargins()
Return type:

QMargins

Returns the margins used around the layout.

By default, QLayout uses the values provided by the style. On most platforms, the margin is 11 pixels in all directions.

Getter of property contentsMarginsᅟ .

contentsRect()
Return type:

QRect

Returns the layout’s geometry() rectangle, but taking into account the contents margins.

abstract count()
Return type:

int

Must be implemented in subclasses to return the number of items in the layout.

See also

itemAt()

getContentsMargins()
Return type:

PyObject

For each of left, top, right and bottom that is not None, stores the size of the margin named in the location the pointer refers to.

By default, QLayout uses the values provided by the style. On most platforms, the margin is 11 pixels in all directions.

indexOf(arg__1)
Parameters:

arg__1 – QLayoutItem

Return type:

int

Searches for layout item layoutItem in this layout (not including child layouts).

Returns the index of layoutItem, or -1 if layoutItem is not found.

indexOf(arg__1)
Parameters:

arg__1 – QWidget

Return type:

int

Searches for widget widget in this layout (not including child layouts).

Returns the index of widget, or -1 if widget is not found.

The default implementation iterates over all items using itemAt() .

isEnabled()
Return type:

bool

Returns true if the layout is enabled; otherwise returns false.

See also

setEnabled()

abstract itemAt(index)
Parameters:

index – int

Return type:

QLayoutItem

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Must be implemented in subclasses to return the layout item at index. If there is no such item, the function must return None. Items are numbered consecutively from 0. If an item is deleted, other items will be renumbered.

This function can be used to iterate over a layout. The following code will draw a rectangle for each layout item in the layout structure of the widget.

def paintLayout(painter, item):

    layout = item.layout()
    if layout:
        for i in range(0, layout.count()):
            paintLayout(painter, layout.itemAt(i))

    painter.drawRect(item.geometry())

def paintEvent(self, arg__0):

    painter = QPainter(self)
    if layout():
        paintLayout(painter, layout())

See also

count() takeAt()

menuBar()
Return type:

QWidget

Returns the menu bar set for this layout, or None if no menu bar is set.

See also

setMenuBar()

parentWidget()
Return type:

QWidget

Returns the parent widget of this layout, or None if this layout is not installed on any widget.

If the layout is a sub-layout, this function returns the parent widget of the parent layout.

See also

parent()

removeItem(arg__1)
Parameters:

arg__1 – QLayoutItem

Removes the layout item item from the layout. It is the caller’s responsibility to delete the item.

Notice that item can be a layout (since QLayout inherits QLayoutItem ).

removeWidget(w)
Parameters:

w – QWidget

Removes the widget widget from the layout. After this call, it is the caller’s responsibility to give the widget a reasonable geometry or to put the widget back into a layout or to explicitly hide it if necessary.

Note

The ownership of widget remains the same as when it was added.

See also

removeItem() setGeometry() addWidget()

replaceWidget(from, to[, options=Qt.FindChildrenRecursively])
Parameters:
Return type:

QLayoutItem

Searches for widget from and replaces it with widget to if found. Returns the layout item that contains the widget from on success. Otherwise None is returned. If options contains Qt::FindChildrenRecursively (the default), sub-layouts are searched for doing the replacement. Any other flag in options is ignored.

Notice that the returned item therefore might not belong to this layout, but to a sub-layout.

The returned layout item is no longer owned by the layout and should be either deleted or inserted to another layout. The widget from is no longer managed by the layout and may need to be deleted or hidden. The parent of widget from is left unchanged.

This function works for the built-in Qt layouts, but might not work for custom layouts.

See also

indexOf()

setAlignment(l, alignment)
Parameters:
Return type:

bool

This is an overloaded function.

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.

setAlignment(w, alignment)
Parameters:
Return type:

bool

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.

setContentsMargins(margins)
Parameters:

margins – QMargins

Sets the margins to use around the layout.

By default, QLayout uses the values provided by the style. On most platforms, the margin is 11 pixels in all directions.

Setter of property contentsMarginsᅟ .

setContentsMargins(left, top, right, bottom)
Parameters:

  • left – int

  • top – int

  • right – int

  • bottom – int

Sets the left, top, right, and bottom margins to use around the layout.

By default, QLayout uses the values provided by the style. On most platforms, the margin is 11 pixels in all directions.

setEnabled(arg__1)
Parameters:

arg__1 – bool

Enables this layout if enable is true, otherwise disables it.

An enabled layout adjusts dynamically to changes; a disabled layout acts as if it did not exist.

By default all layouts are enabled.

See also

isEnabled()

setMenuBar(w)
Parameters:

w – QWidget

Tells the geometry manager to place the menu bar widget at the top of parentWidget() , outside contentsMargins() . All child widgets are placed below the bottom edge of the menu bar.

See also

menuBar()

setSizeConstraint(arg__1)
Parameters:

arg__1 – SizeConstraint

See also

sizeConstraint()

Setter of property sizeConstraintᅟ .

setSpacing(arg__1)
Parameters:

arg__1 – int

See also

spacing()

Setter of property spacingᅟ .

sizeConstraint()
Return type:

SizeConstraint

See also

setSizeConstraint()

Getter of property sizeConstraintᅟ .

spacing()
Return type:

int

See also

setSpacing()

Getter of property spacingᅟ .

abstract takeAt(index)
Parameters:

index – int

Return type:

QLayoutItem

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Must be implemented in subclasses to remove the layout item at index from the layout, and return the item. If there is no such item, the function must do nothing and return 0. Items are numbered consecutively from 0. If an item is removed, other items will be renumbered.

The following code fragment shows a safe way to remove all items from a layout:

child = QLayoutItem()
while (child = layout.takeAt(0)) != None:
    ...
    del child.widget() # del the widget
    del child   # del the layout item

See also

itemAt() count()

totalHeightForWidth(w)
Parameters:

w – int

Return type:

int

totalMaximumSize()
Return type:

QSize

totalMinimumHeightForWidth(w)
Parameters:

w – int

Return type:

int

totalMinimumSize()
Return type:

QSize

totalSizeHint()
Return type:

QSize

unsetContentsMargins()

Unsets any user-defined margins around the layout. The layout will use the default values provided by the style.

Reset function of property contentsMarginsᅟ .

update()

Updates the layout for parentWidget() .

You should generally not need to call this because it is automatically called at the most appropriate times.

See also

activate() invalidate()

widgetEvent(arg__1)
Parameters:

arg__1 – QEvent