QLayoutItem

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

Inheritance diagram of PySide6.QtWidgets.QLayoutItem

Inherited by: QSpacerItem, 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, , , and expanding().

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

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 PySide6.QtWidgets.QLayoutItem([alignment=Qt.Alignment()])
Parameters

alignmentAlignment

PySide6.QtWidgets.QLayoutItem.align
PySide6.QtWidgets.QLayoutItem.alignment()
Return type

Alignment

See also

setAlignment()

PySide6.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()

PySide6.QtWidgets.QLayoutItem.expandingDirections()
Return type

Orientations

PySide6.QtWidgets.QLayoutItem.geometry()
Return type

PySide6.QtCore.QRect

PySide6.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.

PySide6.QtWidgets.QLayoutItem.heightForWidth(arg__1)
Parameters

arg__1 – int

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.

PySide6.QtWidgets.QLayoutItem.invalidate()

Invalidates any cached information in this layout item.

PySide6.QtWidgets.QLayoutItem.isEmpty()
Return type

bool

PySide6.QtWidgets.QLayoutItem.layout()
Return type

PySide6.QtWidgets.QLayout

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

PySide6.QtWidgets.QLayoutItem.maximumSize()
Return type

PySide6.QtCore.QSize

PySide6.QtWidgets.QLayoutItem.minimumHeightForWidth(arg__1)
Parameters

arg__1 – int

Return type

int

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

PySide6.QtWidgets.QLayoutItem.minimumSize()
Return type

PySide6.QtCore.QSize

PySide6.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.

PySide6.QtWidgets.QLayoutItem.setGeometry(arg__1)
Parameters

arg__1PySide6.QtCore.QRect

PySide6.QtWidgets.QLayoutItem.sizeHint()
Return type

PySide6.QtCore.QSize

PySide6.QtWidgets.QLayoutItem.spacerItem()
Return type

PySide6.QtWidgets.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()

PySide6.QtWidgets.QLayoutItem.widget()
Return type

PySide6.QtWidgets.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.