QAbstractItemDelegate¶
The
QAbstractItemDelegate
class is used to display and edit data items from a model. More…
Inherited by: QItemDelegate, QStyledItemDelegate
Synopsis¶
Virtual functions¶
def
createEditor
(parent, option, index)def
destroyEditor
(editor, index)def
editorEvent
(event, model, option, index)def
helpEvent
(event, view, option, index)def
paint
(painter, option, index)def
paintingRoles
()def
setEditorData
(editor, index)def
setModelData
(editor, model, index)def
sizeHint
(option, index)def
updateEditorGeometry
(editor, option, index)
Signals¶
def
closeEditor
(editor[, hint=NoHint])def
commitData
(editor)def
sizeHintChanged
(arg__1)
Static functions¶
def
elidedText
(fontMetrics, width, mode, text)
Detailed Description¶
A
QAbstractItemDelegate
provides the interface and common functionality for delegates in the model/view architecture. Delegates display individual items in views, and handle the editing of model data.The
QAbstractItemDelegate
class is one of the Model/View Classes and is part of Qt’s model/view framework .To render an item in a custom way, you must implement
paint()
andsizeHint()
. TheQItemDelegate
class provides default implementations for these functions; if you do not need custom rendering, subclass that class instead.We give an example of drawing a progress bar in items; in our case for a package management program.
We create the
WidgetDelegate
class, which inherits fromQStyledItemDelegate
. We do the drawing in thepaint()
function:class WidgetDelegate (QStyledItemDelegate): # ... def paint(painter, option, index): if index.column() == 1: progress = index.data().toInt() progressBarOption = QStyleOptionProgressBar() progressBarOption.rect = option.rect progressBarOption.minimum = 0 progressBarOption.maximum = 100 progressBarOption.progress = progress progressBarOption.text = QString::number(progress) + "%" progressBarOption.textVisible = True QApplication.style().drawControl(QStyle.CE_ProgressBar, progressBarOption, painter) else: QStyledItemDelegate.paint(self, painter, option, index)Notice that we use a
QStyleOptionProgressBar
and initialize its members. We can then use the currentQStyle
to draw it.To provide custom editing, there are two approaches that can be used. The first approach is to create an editor widget and display it directly on top of the item. To do this you must reimplement
createEditor()
to provide an editor widget,setEditorData()
to populate the editor with the data from the model, andsetModelData()
so that the delegate can update the model with data from the editor.The second approach is to handle user events directly by reimplementing
editorEvent()
.
-
class
QAbstractItemDelegate
([parent=None])¶ - param parent
QObject
Creates a new abstract item delegate with the given
parent
.
-
PySide2.QtWidgets.QAbstractItemDelegate.
EndEditHint
¶ This enum describes the different hints that the delegate can give to the model and view components to make editing data in a model a comfortable experience for the user.
Constant
Description
QAbstractItemDelegate.NoHint
There is no recommended action to be performed.
These hints let the delegate influence the behavior of the view:
Constant
Description
QAbstractItemDelegate.EditNextItem
The view should use the delegate to open an editor on the next item in the view.
QAbstractItemDelegate.EditPreviousItem
The view should use the delegate to open an editor on the previous item in the view.
Note that custom views may interpret the concepts of next and previous differently.
The following hints are most useful when models are used that cache data, such as those that manipulate data locally in order to increase performance or conserve network bandwidth.
Constant
Description
QAbstractItemDelegate.SubmitModelCache
If the model caches data, it should write out cached data to the underlying data store.
QAbstractItemDelegate.RevertModelCache
If the model caches data, it should discard cached data and replace it with data from the underlying data store.
Although models and views should respond to these hints in appropriate ways, custom components may ignore any or all of them if they are not relevant.
-
PySide2.QtWidgets.QAbstractItemDelegate.
closeEditor
(editor[, hint=NoHint])¶ - Parameters
editor –
QWidget
hint –
EndEditHint
-
PySide2.QtWidgets.QAbstractItemDelegate.
createEditor
(parent, option, index)¶ - Parameters
parent –
QWidget
option –
QStyleOptionViewItem
index –
QModelIndex
- Return type
Returns the editor to be used for editing the data item with the given
index
. Note that the index contains information about the model being used. The editor’s parent widget is specified byparent
, and the item options byoption
.The base implementation returns
None
. If you want custom editing you will need to reimplement this function.The returned editor widget should have
StrongFocus
; otherwise,QMouseEvent
s received by the widget will propagate to the view. The view’s background will shine through unless the editor paints its own background (e.g., withsetAutoFillBackground()
).See also
-
PySide2.QtWidgets.QAbstractItemDelegate.
destroyEditor
(editor, index)¶ - Parameters
editor –
QWidget
index –
QModelIndex
Called when the
editor
is no longer needed for editing the data item with the givenindex
and should be destroyed. The default behavior is a call todeleteLater
on the editor. It is possible e.g. to avoid this delete by reimplementing this function.See also
-
PySide2.QtWidgets.QAbstractItemDelegate.
editorEvent
(event, model, option, index)¶ - Parameters
event –
QEvent
model –
QAbstractItemModel
option –
QStyleOptionViewItem
index –
QModelIndex
- Return type
bool
When editing of an item starts, this function is called with the
event
that triggered the editing, themodel
, theindex
of the item, and theoption
used for rendering the item.Mouse events are sent to even if they don’t start editing of the item. This can, for instance, be useful if you wish to open a context menu when the right mouse button is pressed on an item.
The base implementation returns
false
(indicating that it has not handled the event).
-
static
PySide2.QtWidgets.QAbstractItemDelegate.
elidedText
(fontMetrics, width, mode, text)¶ - Parameters
fontMetrics –
QFontMetrics
width –
int
mode –
TextElideMode
text – unicode
- Return type
unicode
Use
elidedText()
instead.For example, if you have code like
you can rewrite it as
-
PySide2.QtWidgets.QAbstractItemDelegate.
helpEvent
(event, view, option, index)¶ - Parameters
event –
QHelpEvent
view –
QAbstractItemView
option –
QStyleOptionViewItem
index –
QModelIndex
- Return type
bool
Whenever a help event occurs, this function is called with the
event
view
option
and theindex
that corresponds to the item where the event occurs.Returns
true
if the delegate can handle the event; otherwise returnsfalse
. A return value of true indicates that the data obtained using the index had the required role.For
ToolTip
andWhatsThis
events that were handled successfully, the relevant popup may be shown depending on the user’s system configuration.See also
-
PySide2.QtWidgets.QAbstractItemDelegate.
paint
(painter, option, index)¶ - Parameters
painter –
QPainter
option –
QStyleOptionViewItem
index –
QModelIndex
This pure abstract function must be reimplemented if you want to provide custom rendering. Use the
painter
and styleoption
to render the item specified by the itemindex
.If you reimplement this you must also reimplement
sizeHint()
.
-
PySide2.QtWidgets.QAbstractItemDelegate.
paintingRoles
()¶ - Return type
This virtual method is reserved and will be used in Qt 5.1.
-
PySide2.QtWidgets.QAbstractItemDelegate.
setEditorData
(editor, index)¶ - Parameters
editor –
QWidget
index –
QModelIndex
Sets the contents of the given
editor
to the data for the item at the givenindex
. Note that the index contains information about the model being used.The base implementation does nothing. If you want custom editing you will need to reimplement this function.
See also
-
PySide2.QtWidgets.QAbstractItemDelegate.
setModelData
(editor, model, index)¶ - Parameters
editor –
QWidget
model –
QAbstractItemModel
index –
QModelIndex
Sets the data for the item at the given
index
in themodel
to the contents of the giveneditor
.The base implementation does nothing. If you want custom editing you will need to reimplement this function.
See also
-
PySide2.QtWidgets.QAbstractItemDelegate.
sizeHint
(option, index)¶ - Parameters
option –
QStyleOptionViewItem
index –
QModelIndex
- Return type
QSize
This pure abstract function must be reimplemented if you want to provide custom rendering. The options are specified by
option
and the model item byindex
.If you reimplement this you must also reimplement
paint()
.
-
PySide2.QtWidgets.QAbstractItemDelegate.
sizeHintChanged
(arg__1)¶ - Parameters
arg__1 –
QModelIndex
-
PySide2.QtWidgets.QAbstractItemDelegate.
updateEditorGeometry
(editor, option, index)¶ - Parameters
editor –
QWidget
option –
QStyleOptionViewItem
index –
QModelIndex
Updates the geometry of the
editor
for the item with the givenindex
, according to the rectangle specified in theoption
. If the item has an internal layout, the editor will be laid out accordingly. Note that the index contains information about the model being used.The base implementation does nothing. If you want custom editing you must reimplement this function.
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