QLayoutItem

The QLayoutItem class provides an abstract item that a QLayout manipulates. More

Inheritance diagram of PySide2.QtWidgets.QLayoutItem

Inherited by: QBoxLayout, QFormLayout, QGridLayout, QHBoxLayout, QLayout, QSpacerItem, QStackedLayout, QVBoxLayout, QWidgetItem

Synopsis

Functions

Virtual functions

Detailed Description

This is used by custom layouts.

Pure virtual functions are provided to return information about the layout, including, sizeHint() , minimumSize() , maximumSize() and expanding().

The layout’s geometry can be set and retrieved with setGeometry() and geometry() , and its alignment with setAlignment() and alignment() .

isEmpty() returns whether the layout item is empty. If the concrete item is a QWidget , it can be retrieved using widget() . Similarly for layout() and spacerItem() .

Some layouts have width and height interdependencies. These can be expressed using hasHeightForWidth() , heightForWidth() , and minimumHeightForWidth() . For more explanation see the Qt Quarterly article Trading Height for Width.

See also

QLayout

class QLayoutItem([alignment=Qt.Alignment()])
param alignment

Alignment

Constructs a layout item with an alignment . Not all subclasses support alignment.

PySide2.QtWidgets.QLayoutItem.align
PySide2.QtWidgets.QLayoutItem.alignment()
Return type

Alignment

Returns the alignment of this item.

See also

setAlignment()

PySide2.QtWidgets.QLayoutItem.controlTypes()
Return type

ControlTypes

Returns the control type(s) for the layout item. For a QWidgetItem , the control type comes from the widget’s size policy; for a QLayoutItem , the control types is derived from the layout’s contents.

See also

controlType()

PySide2.QtWidgets.QLayoutItem.expandingDirections()
Return type

Orientations

Returns whether this layout item can make use of more space than sizeHint() . A value of Vertical or Horizontal means that it wants to grow in only one dimension, whereas Vertical | Horizontal means that it wants to grow in both dimensions.

PySide2.QtWidgets.QLayoutItem.geometry()
Return type

QRect

Returns the rectangle covered by this layout item.

See also

setGeometry()

PySide2.QtWidgets.QLayoutItem.hasHeightForWidth()
Return type

bool

Returns true if this layout’s preferred height depends on its width; otherwise returns false . The default implementation returns false.

Reimplement this function in layout managers that support height for width.

PySide2.QtWidgets.QLayoutItem.heightForWidth(arg__1)
Parameters

arg__1int

Return type

int

Returns the preferred height for this layout item, given the width, which is not used in this default implementation.

The default implementation returns -1, indicating that the preferred height is independent of the width of the item. Using the function hasHeightForWidth() will typically be much faster than calling this function and testing for -1.

Reimplement this function in layout managers that support height for width. A typical implementation will look like this:

def heightForWidth(self, w):
    if cache_dirty or cached_width != w:
        h = calculateHeightForWidth(w)
        self.cached_hfw = h
        return h
    return cached_hfw

Caching is strongly recommended; without it layout will take exponential time.

PySide2.QtWidgets.QLayoutItem.invalidate()

Invalidates any cached information in this layout item.

PySide2.QtWidgets.QLayoutItem.isEmpty()
Return type

bool

Implemented in subclasses to return whether this item is empty, i.e. whether it contains any widgets.

PySide2.QtWidgets.QLayoutItem.layout()
Return type

QLayout

If this item is a QLayout , it is returned as a QLayout ; otherwise None is returned. This function provides type-safe casting.

PySide2.QtWidgets.QLayoutItem.maximumSize()
Return type

QSize

Implemented in subclasses to return the maximum size of this item.

PySide2.QtWidgets.QLayoutItem.minimumHeightForWidth(arg__1)
Parameters

arg__1int

Return type

int

Returns the minimum height this widget needs for the given width, w . The default implementation simply returns heightForWidth (w ).

PySide2.QtWidgets.QLayoutItem.minimumSize()
Return type

QSize

Implemented in subclasses to return the minimum size of this item.

PySide2.QtWidgets.QLayoutItem.setAlignment(a)
Parameters

aAlignment

Sets the alignment of this item to alignment .

Note

Item alignment is only supported by QLayoutItem subclasses where it would have a visual effect. Except for QSpacerItem , which provides blank space for layouts, all public Qt classes that inherit QLayoutItem support item alignment.

See also

alignment()

PySide2.QtWidgets.QLayoutItem.setGeometry(arg__1)
Parameters

arg__1QRect

Implemented in subclasses to set this item’s geometry to r .

See also

geometry()

PySide2.QtWidgets.QLayoutItem.sizeHint()
Return type

QSize

Implemented in subclasses to return the preferred size of this item.

PySide2.QtWidgets.QLayoutItem.spacerItem()
Return type

QSpacerItem

If this item is a QSpacerItem , it is returned as a QSpacerItem ; otherwise None is returned. This function provides type-safe casting.

See also

layout() widget()

PySide2.QtWidgets.QLayoutItem.widget()
Return type

QWidget

If this item manages a QWidget , returns that widget. Otherwise, None is returned.

Note

While the functions layout() and spacerItem() perform casts, this function returns another object: QLayout and QSpacerItem inherit QLayoutItem , while QWidget does not.