QItemDelegate¶
The
QItemDelegate
class provides display and editing facilities for data items from a model. More…
Synopsis¶
Functions¶
def
decoration
(option, variant)def
doCheck
(option, bounding, variant)def
drawBackground
(painter, option, index)def
hasClipping
()def
itemEditorFactory
()def
rect
(option, index, role)def
setClipping
(clip)def
setItemEditorFactory
(factory)def
setOptions
(index, option)def
textRectangle
(painter, rect, font, text)
Virtual functions¶
def
drawCheck
(painter, option, rect, state)def
drawDecoration
(painter, option, rect, pixmap)def
drawDisplay
(painter, option, rect, text)def
drawFocus
(painter, option, rect)
Static functions¶
def
selectedPixmap
(pixmap, palette, enabled)
Detailed Description¶
QItemDelegate
can be used to provide custom display features and editor widgets for item views based onQAbstractItemView
subclasses. Using a delegate for this purpose allows the display and editing mechanisms to be customized and developed independently from the model and view.The
QItemDelegate
class is one of the Model/View Classes and is part of Qt’s model/view framework . Note thatQStyledItemDelegate
has taken over the job of drawing Qt’s item views. We recommend the use ofQStyledItemDelegate
when creating new delegates.When displaying items from a custom model in a standard view, it is often sufficient to simply ensure that the model returns appropriate data for each of the
roles
that determine the appearance of items in views. The default delegate used by Qt’s standard views uses this role information to display items in most of the common forms expected by users. However, it is sometimes necessary to have even more control over the appearance of items than the default delegate can provide.This class provides default implementations of the functions for painting item data in a view and editing data from item models. Default implementations of the
paint()
andsizeHint()
virtual functions, defined inQAbstractItemDelegate
, are provided to ensure that the delegate implements the correct basic behavior expected by views. You can reimplement these functions in subclasses to customize the appearance of items.When editing data in an item view,
QItemDelegate
provides an editor widget, which is a widget that is placed on top of the view while editing takes place. Editors are created with aQItemEditorFactory
; a default static instance provided byQItemEditorFactory
is installed on all item delegates. You can set a custom factory usingsetItemEditorFactory()
or set a new default factory withsetDefaultFactory()
. It is the data stored in the item model with theEditRole
that is edited.Only the standard editing functions for widget-based delegates are reimplemented here:
createEditor()
returns the widget used to change data from the model and can be reimplemented to customize editing behavior.
setEditorData()
provides the widget with data to manipulate.
updateEditorGeometry()
ensures that the editor is displayed correctly with respect to the item view.
setModelData()
returns updated data to the model.The
closeEditor()
signal indicates that the user has completed editing the data, and that the editor widget can be destroyed.
Standard Roles and Data Types¶
The default delegate used by the standard views supplied with Qt associates each standard role (defined by
ItemDataRole
) with certain data types. Models that return data in these types can influence the appearance of the delegate as described in the following table.
Role
Accepted Types
BackgroundRole
QBrush
(
BackgroundColorRole
QColor
(obsolete; useBackgroundRole
instead)
CheckStateRole
CheckState
DecorationRole
QIcon
,QPixmap
andQColor
DisplayRole
QString
and types with a string representation
EditRole
See
QItemEditorFactory
for details
FontRole
QFont
SizeHintRole
QSize
TextAlignmentRole
Alignment
ForegroundRole
QBrush
(
TextColorRole
QColor
(obsolete; useForegroundRole
instead)If the default delegate does not allow the level of customization that you need, either for display purposes or for editing data, it is possible to subclass
QItemDelegate
to implement the desired behavior.
Subclassing¶
When subclassing
QItemDelegate
to create a delegate that displays items using a custom renderer, it is important to ensure that the delegate can render items suitably for all the required states; e.g. selected, disabled, checked. The documentation for thepaint()
function contains some hints to show how this can be achieved.You can provide custom editors by using a
QItemEditorFactory
. The Color Editor Factory Example shows how a custom editor can be made available to delegates with the default item editor factory. This way, there is no need to subclassQItemDelegate
. An alternative is to reimplementcreateEditor()
,setEditorData()
,setModelData()
, andupdateEditorGeometry()
. This process is described in the Spin Box Delegate Example .
QStyledItemDelegate vs. QItemDelegate¶
Since Qt 4.4, there are two delegate classes:
QItemDelegate
andQStyledItemDelegate
. However, the default delegate isQStyledItemDelegate
. These two classes are independent alternatives to painting and providing editors for items in views. The difference between them is thatQStyledItemDelegate
uses the current style to paint its items. We therefore recommend usingQStyledItemDelegate
as the base class when implementing custom delegates or when working with Qt style sheets. The code required for either class should be equal unless the custom delegate needs to use the style for drawing.See also
Delegate Classes
QStyledItemDelegate
QAbstractItemDelegate
Spin Box Delegate Example Settings Editor Example Icons Example
- class PySide2.QtWidgets.QItemDelegate([parent=None])¶
- param parent:
Constructs an item delegate with the given
parent
.
- PySide2.QtWidgets.QItemDelegate.decoration(option, variant)¶
- Parameters:
variant – object
- Return type:
Returns the pixmap used to decorate the root of the item view. The style
option
controls the appearance of the root; thevariant
refers to the data associated with an item.
- PySide2.QtWidgets.QItemDelegate.doCheck(option, bounding, variant)¶
- Parameters:
bounding –
PySide2.QtCore.QRect
variant – object
- Return type:
- PySide2.QtWidgets.QItemDelegate.drawBackground(painter, option, index)¶
- Parameters:
painter –
PySide2.QtGui.QPainter
index –
PySide2.QtCore.QModelIndex
Renders the item background for the given
index
, using the givenpainter
and styleoption
.
- PySide2.QtWidgets.QItemDelegate.drawCheck(painter, option, rect, state)¶
- Parameters:
painter –
PySide2.QtGui.QPainter
rect –
PySide2.QtCore.QRect
state –
CheckState
Renders a check indicator within the rectangle specified by
rect
, using the givenpainter
and styleoption
, using the givenstate
.
- PySide2.QtWidgets.QItemDelegate.drawDecoration(painter, option, rect, pixmap)¶
- Parameters:
painter –
PySide2.QtGui.QPainter
rect –
PySide2.QtCore.QRect
pixmap –
PySide2.QtGui.QPixmap
Renders the decoration
pixmap
within the rectangle specified byrect
using the givenpainter
and styleoption
.
- PySide2.QtWidgets.QItemDelegate.drawDisplay(painter, option, rect, text)¶
- Parameters:
painter –
PySide2.QtGui.QPainter
rect –
PySide2.QtCore.QRect
text – str
Renders the item view
text
within the rectangle specified byrect
using the givenpainter
and styleoption
.
- PySide2.QtWidgets.QItemDelegate.drawFocus(painter, option, rect)¶
- Parameters:
painter –
PySide2.QtGui.QPainter
rect –
PySide2.QtCore.QRect
Renders the region within the rectangle specified by
rect
, indicating that it has the focus, using the givenpainter
and styleoption
.
- PySide2.QtWidgets.QItemDelegate.hasClipping()¶
- Return type:
bool
This property holds if the delegate should clip the paint events.
This property will set the paint clip to the size of the item. The default value is on. It is useful for cases such as when images are larger than the size of the item.
- PySide2.QtWidgets.QItemDelegate.itemEditorFactory()¶
- Return type:
Returns the editor factory used by the item delegate. If no editor factory is set, the function will return null.
See also
- PySide2.QtWidgets.QItemDelegate.rect(option, index, role)¶
- Parameters:
index –
PySide2.QtCore.QModelIndex
role – int
- Return type:
Only used (and usable) for
DecorationRole
andCheckStateRole
- static PySide2.QtWidgets.QItemDelegate.selectedPixmap(pixmap, palette, enabled)¶
- Parameters:
pixmap –
PySide2.QtGui.QPixmap
palette –
PySide2.QtGui.QPalette
enabled – bool
- Return type:
Returns the selected version of the given
pixmap
using the givenpalette
. Theenabled
argument decides whether the normal or disabled highlight color of the palette is used.
- PySide2.QtWidgets.QItemDelegate.setClipping(clip)¶
- Parameters:
clip – bool
This property holds if the delegate should clip the paint events.
This property will set the paint clip to the size of the item. The default value is on. It is useful for cases such as when images are larger than the size of the item.
- PySide2.QtWidgets.QItemDelegate.setItemEditorFactory(factory)¶
- Parameters:
factory –
PySide2.QtWidgets.QItemEditorFactory
Sets the editor factory to be used by the item delegate to be the
factory
specified. If no editor factory is set, the item delegate will use the default editor factory.See also
- PySide2.QtWidgets.QItemDelegate.setOptions(index, option)¶
- Parameters:
index –
PySide2.QtCore.QModelIndex
- Return type:
- PySide2.QtWidgets.QItemDelegate.textRectangle(painter, rect, font, text)¶
- Parameters:
painter –
PySide2.QtGui.QPainter
rect –
PySide2.QtCore.QRect
font –
PySide2.QtGui.QFont
text – str
- Return type:
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