QDataWidgetMapper

The QDataWidgetMapper class provides mapping between a section of a data model to widgets. More…

Synopsis

Functions

• def addMapping (widget, section)

• def addMapping (widget, section, propertyName)

• def clearMapping ()

• def currentIndex ()

• def itemDelegate ()

• def mappedPropertyName (widget)

• def mappedSection (widget)

• def mappedWidgetAt (section)

• def model ()

• def orientation ()

• def removeMapping (widget)

• def rootIndex ()

• def setItemDelegate (delegate)

• def setModel (model)

• def setOrientation (aOrientation)

• def setRootIndex (index)

• def setSubmitPolicy (policy)

• def submitPolicy ()

Virtual functions

• def setCurrentIndex (index)

Slots

• def revert ()

• def setCurrentModelIndex (index)

• def submit ()

• def toFirst ()

• def toLast ()

• def toNext ()

• def toPrevious ()

Signals

• def currentIndexChanged (index)

Detailed Description

QDataWidgetMapper can be used to create data-aware widgets by mapping them to sections of an item model. A section is a column of a model if the orientation is horizontal (the default), otherwise a row.

Every time the current index changes, each widget is updated with data from the model via the property specified when its mapping was made. If the user edits the contents of a widget, the changes are read using the same property and written back to the model. By default, each widget’s user property is used to transfer data between the model and the widget. Since Qt 4.3, an additional addMapping() function enables a named property to be used instead of the default user property.

It is possible to set an item delegate to support custom widgets. By default, a QItemDelegate is used to synchronize the model with the widgets.

Let us assume that we have an item model named model with the following contents:

1	Qt Norway	Oslo
2	Qt Australia	Brisbane
3	Qt USA	Palo Alto
4	Qt China	Beijing
5	Qt Germany	Berlin

The following code will map the columns of the model to widgets called mySpinBox , myLineEdit and myCountryChooser :

mapper = QDataWidgetMapper
mapper.setModel(model)
mapper.addMapping(mySpinBox, 0)
mapper.addMapping(myLineEdit, 1)
mapper.addMapping(myCountryChooser, 2)
mapper.toFirst()

After the call to toFirst() , mySpinBox displays the value 1 , myLineEdit displays Qt Norway and myCountryChooser displays Oslo . The navigational functions toFirst() , toNext() , toPrevious() , toLast() and setCurrentIndex() can be used to navigate in the model and update the widgets with contents from the model.

The setRootIndex() function enables a particular item in a model to be specified as the root index - children of this item will be mapped to the relevant widgets in the user interface.

QDataWidgetMapper supports two submit policies, AutoSubmit and ManualSubmit . AutoSubmit will update the model as soon as the current widget loses focus, ManualSubmit will not update the model unless submit() is called. ManualSubmit is useful when displaying a dialog that lets the user cancel all modifications. Also, other views that display the model won’t update until the user finishes all their modifications and submits.

Note that QDataWidgetMapper keeps track of external modifications. If the contents of the model are updated in another module of the application, the widgets are updated as well.

See also

QAbstractItemModel QAbstractItemDelegate

class QDataWidgetMapper([parent=None])

param parent

QObject

Constructs a new QDataWidgetMapper with parent object parent . By default, the orientation is horizontal and the submit policy is AutoSubmit .

See also

setOrientation() setSubmitPolicy()

PySide2.QtWidgets.QDataWidgetMapper.SubmitPolicy

This enum describes the possible submit policies a QDataWidgetMapper supports.

Constant	Description
QDataWidgetMapper.AutoSubmit	Whenever a widget loses focus, the widget’s current value is set to the item model.
QDataWidgetMapper.ManualSubmit	The model is not updated until submit() is called.

PySide2.QtWidgets.QDataWidgetMapper.addMapping(widget, section)

Parameters

• widget – QWidget

• section – int

Adds a mapping between a widget and a section from the model. The section is a column in the model if the orientation is horizontal (the default), otherwise a row.

For the following example, we assume a model myModel that has two columns: the first one contains the names of people in a group, and the second column contains their ages. The first column is mapped to the QLineEdit nameLineEdit , and the second is mapped to the QSpinBox ageSpinBox :

mapper = QDataWidgetMapper()
mapper.setModel(myModel)
mapper.addMapping(nameLineEdit, 0)
mapper.addMapping(ageSpinBox, 1)

Notes:

• If the widget is already mapped to a section, the old mapping will be replaced by the new one.

• Only one-to-one mappings between sections and widgets are allowed. It is not possible to map a single section to multiple widgets, or to map a single widget to multiple sections.

See also

removeMapping() mappedSection() clearMapping()

PySide2.QtWidgets.QDataWidgetMapper.addMapping(widget, section, propertyName)

Parameters

• widget – QWidget

• section – int

• propertyName – QByteArray

Essentially the same as addMapping() , but adds the possibility to specify the property to use specifying propertyName .

See also

addMapping()

PySide2.QtWidgets.QDataWidgetMapper.clearMapping()

Clears all mappings.

See also

addMapping() removeMapping()

PySide2.QtWidgets.QDataWidgetMapper.currentIndex()

Return type

int

See also

setCurrentIndex()

PySide2.QtWidgets.QDataWidgetMapper.currentIndexChanged(index)

Parameters

index – int

PySide2.QtWidgets.QDataWidgetMapper.itemDelegate()

Return type

QAbstractItemDelegate

Returns the current item delegate.

See also

setItemDelegate()

PySide2.QtWidgets.QDataWidgetMapper.mappedPropertyName(widget)

Parameters

widget – QWidget

Return type

QByteArray

Returns the name of the property that is used when mapping data to the given widget .

See also

mappedSection() addMapping() removeMapping()

PySide2.QtWidgets.QDataWidgetMapper.mappedSection(widget)

Parameters

widget – QWidget

Return type

int

Returns the section the widget is mapped to or -1 if the widget is not mapped.

See also

addMapping() removeMapping()

PySide2.QtWidgets.QDataWidgetMapper.mappedWidgetAt(section)

Parameters

section – int

Return type

QWidget

Returns the widget that is mapped at section , or 0 if no widget is mapped at that section.

See also

addMapping() removeMapping()

PySide2.QtWidgets.QDataWidgetMapper.model()

Return type

QAbstractItemModel

Returns the current model.

See also

setModel()

PySide2.QtWidgets.QDataWidgetMapper.orientation()

Return type

Orientation

See also

setOrientation()

PySide2.QtWidgets.QDataWidgetMapper.removeMapping(widget)

Parameters

widget – QWidget

Removes the mapping for the given widget .

See also

addMapping() clearMapping()

PySide2.QtWidgets.QDataWidgetMapper.revert()

Repopulates all widgets with the current data of the model. All unsubmitted changes will be lost.

See also

submit() setSubmitPolicy()

PySide2.QtWidgets.QDataWidgetMapper.rootIndex()

Return type

QModelIndex

Returns the current root index.

See also

setRootIndex()

PySide2.QtWidgets.QDataWidgetMapper.setCurrentIndex(index)

Parameters

index – int

See also

currentIndex()

PySide2.QtWidgets.QDataWidgetMapper.setCurrentModelIndex(index)

Parameters

index – QModelIndex

Sets the current index to the row of the index if the orientation is horizontal (the default), otherwise to the column of the index .

Calls setCurrentIndex() internally. This convenience slot can be connected to the signal currentRowChanged() or currentColumnChanged() of another view’s selection model .

The following example illustrates how to update all widgets with new data whenever the selection of a QTableView named myTableView changes:

mapper = QDataWidgetMapper()
connect(myTableView.selectionModel(), SIGNAL("currentRowChanged(QModelIndex,QModelIndex)"),
        mapper, SLOT(setCurrentModelIndex(QModelIndex)))

See also

currentIndex()

PySide2.QtWidgets.QDataWidgetMapper.setItemDelegate(delegate)

Parameters

delegate – QAbstractItemDelegate

Sets the item delegate to delegate . The delegate will be used to write data from the model into the widget and from the widget to the model, using setEditorData() and setModelData() .

The delegate also decides when to apply data and when to change the editor, using commitData() and closeEditor() .

Warning

You should not share the same instance of a delegate between widget mappers or views. Doing so can cause incorrect or unintuitive editing behavior since each view connected to a given delegate may receive the closeEditor() signal, and attempt to access, modify or close an editor that has already been closed.

See also

itemDelegate()

PySide2.QtWidgets.QDataWidgetMapper.setModel(model)

Parameters

model – QAbstractItemModel

Sets the current model to model . If another model was set, all mappings to that old model are cleared.

See also

model()

PySide2.QtWidgets.QDataWidgetMapper.setOrientation(aOrientation)

Parameters

aOrientation – Orientation

See also

orientation()

PySide2.QtWidgets.QDataWidgetMapper.setRootIndex(index)

Parameters

index – QModelIndex

Sets the root item to index . This can be used to display a branch of a tree. Pass an invalid model index to display the top-most branch.

See also

rootIndex()

PySide2.QtWidgets.QDataWidgetMapper.setSubmitPolicy(policy)

Parameters

policy – SubmitPolicy

See also

submitPolicy()

PySide2.QtWidgets.QDataWidgetMapper.submit()

Return type

bool

Submits all changes from the mapped widgets to the model.

For every mapped section, the item delegate reads the current value from the widget and sets it in the model. Finally, the model’s submit() method is invoked.

Returns true if all the values were submitted, otherwise false.

Note: For database models, lastError() can be used to retrieve the last error.

See also

revert() setSubmitPolicy()

PySide2.QtWidgets.QDataWidgetMapper.submitPolicy()

Return type

SubmitPolicy

See also

setSubmitPolicy()

PySide2.QtWidgets.QDataWidgetMapper.toFirst()

Populates the widgets with data from the first row of the model if the orientation is horizontal (the default), otherwise with data from the first column.

This is equivalent to calling setCurrentIndex(0) .

See also

toLast() setCurrentIndex()

PySide2.QtWidgets.QDataWidgetMapper.toLast()

Populates the widgets with data from the last row of the model if the orientation is horizontal (the default), otherwise with data from the last column.

Calls setCurrentIndex() internally.

See also

toFirst() setCurrentIndex()

PySide2.QtWidgets.QDataWidgetMapper.toNext()

Populates the widgets with data from the next row of the model if the orientation is horizontal (the default), otherwise with data from the next column.

Calls setCurrentIndex() internally. Does nothing if there is no next row in the model.

See also

toPrevious() setCurrentIndex()

PySide2.QtWidgets.QDataWidgetMapper.toPrevious()

Populates the widgets with data from the previous row of the model if the orientation is horizontal (the default), otherwise with data from the previous column.

Calls setCurrentIndex() internally. Does nothing if there is no previous row in the model.

See also

toNext() setCurrentIndex()