com.trolltech.qt.gui
Class QDataWidgetMapper

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.gui.QDataWidgetMapper
All Implemented Interfaces:
QtJambiInterface

public class QDataWidgetMapper
extends QObject

The QDataWidgetMapper class provides mapping between a section of a data model to widgets. 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 Nokia Corporation and/or its subsidiary(-ies) Oslo
2 Trolltech Pty Brisbane
3 Trolltech Inc Palo Alto
4 Trolltech China Beijing
5 Trolltech GmbH Berlin
The following code will map the columns of the model to widgets called mySpinBox, myLineEdit and myCountryChooser:
    QDataWidgetMapper mapper = new 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 Nokia Corporation and/or its subsidiary(-ies) 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, and QAbstractItemDelegate.


Nested Class Summary
static class QDataWidgetMapper.SubmitPolicy
          This enum describes the possible submit policies a QDataWidgetMapper supports.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 QSignalEmitter.Signal1 currentIndexChanged
          This signal takes 1 generic argument(s).
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QDataWidgetMapper()
          Constructs a new QDataWidgetMapper with parent object parent.
QDataWidgetMapper(QObject parent)
          Constructs a new QDataWidgetMapper with parent object parent.
 
Method Summary
 void addMapping(QWidget widget, int section)
          Adds a mapping between a widget and a section from the model.
 void addMapping(QWidget widget, int section, QByteArray propertyName)
          Essentially the same as addMapping(), but adds the possibility to specify the property to use specifying propertyName.
 void clearMapping()
          Clears all mappings.
 int currentIndex()
          This property holds the current row or column.
 QAbstractItemDelegate itemDelegate()
          Returns the current item delegate.
 QByteArray mappedPropertyName(QWidget widget)
          Returns the name of the property that is used when mapping data to the given widget.
 int mappedSection(QWidget widget)
          Returns the section the widget is mapped to or -1 if the widget is not mapped.
 QWidget mappedWidgetAt(int section)
          Returns the widget that is mapped at section, or 0 if no widget is mapped at that section.
 QAbstractItemModel model()
          Returns the current model.
 Qt.Orientation orientation()
          This property holds the orientation of the model.
 void removeMapping(QWidget widget)
          Removes the mapping for the given widget.
 void revert()
          Repopulates all widgets with the current data of the model.
 com.trolltech.qt.core.QModelIndex rootIndex()
          Returns the current root index.
 void setCurrentIndex(int index)
          This property holds the current row or column.
 void setCurrentModelIndex(com.trolltech.qt.core.QModelIndex index)
          Sets the current index to the row of the index if the orientation is horizontal (the default), otherwise to the column of the index.
 void setItemDelegate(QAbstractItemDelegate delegate)
          Sets the item delegate to delegate.
 void setModel(QAbstractItemModel model)
          Sets the current model to model.
 void setOrientation(Qt.Orientation aOrientation)
          This property holds the orientation of the model.
 void setRootIndex(com.trolltech.qt.core.QModelIndex index)
          Sets the root item to index.
 void setSubmitPolicy(QDataWidgetMapper.SubmitPolicy policy)
          This property holds the current submit policy.
 boolean submit()
          Submits all changes from the mapped widgets to the model.
 QDataWidgetMapper.SubmitPolicy submitPolicy()
          This property holds the current submit policy.
 void 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.
 void 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.
 void 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.
 void 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.
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Field Detail

currentIndexChanged

public final QSignalEmitter.Signal1 currentIndexChanged

This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <java.lang.Integer(named: index)>:

This signal is emitted after the current index has changed and all widgets were populated with new data. index is the new current index.

See also:
currentIndex(), and setCurrentIndex().

Constructor Detail

QDataWidgetMapper

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

See also:
setOrientation(), and setSubmitPolicy().


QDataWidgetMapper

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

See also:
setOrientation(), and setSubmitPolicy().

Method Detail

addMapping

public final void addMapping(QWidget widget,
                             int section)
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 QLineEditnameLineEdit, and the second is mapped to the QSpinBoxageSpinBox:

    QDataWidgetMapper mapper = new QDataWidgetMapper();
    mapper.setModel(model);
    mapper.addMapping(nameLineEdit, 0);
    mapper.addMapping(ageSpinBox, 1);
Notes:

See also:
removeMapping(), mappedSection(), and clearMapping().


addMapping

public final void addMapping(QWidget widget,
                             int section,
                             QByteArray propertyName)
Essentially the same as addMapping(), but adds the possibility to specify the property to use specifying propertyName.

See also:
addMapping().


clearMapping

public final void clearMapping()
Clears all mappings.

See also:
addMapping(), and removeMapping().


currentIndex

public final int currentIndex()
This property holds the current row or column. The widgets are populated with with data from the row at index if the orientation is horizontal (the default), otherwise with data from the column at index.

See also:
setCurrentModelIndex(), toFirst(), toNext(), toPrevious(), and toLast().


itemDelegate

public final QAbstractItemDelegate itemDelegate()
Returns the current item delegate.

See also:
setItemDelegate().


mappedPropertyName

public final QByteArray mappedPropertyName(QWidget widget)
Returns the name of the property that is used when mapping data to the given widget.

See also:
mappedSection(), addMapping(), and removeMapping().


mappedSection

public final int mappedSection(QWidget widget)
Returns the section the widget is mapped to or -1 if the widget is not mapped.

See also:
addMapping(), and removeMapping().


mappedWidgetAt

public final QWidget mappedWidgetAt(int section)
Returns the widget that is mapped at section, or 0 if no widget is mapped at that section.

See also:
addMapping(), and removeMapping().


model

public final QAbstractItemModel model()
Returns the current model.

See also:
setModel().


orientation

public final Qt.Orientation orientation()
This property holds the orientation of the model. If the orientation is Qt::Horizontal (the default), a widget is mapped to a column of a data model. The widget will be populated with the model's data from its mapped column and the row that currentIndex() points at.

Use Qt::Horizontal for tabular data that looks like this:

1 Nokia Corporation and/or its subsidiary(-ies) Oslo
2 Trolltech Pty Brisbane
3 Trolltech Inc Silicon Valley
4 Trolltech China Beijing
5 Trolltech GmbH Berlin
If the orientation is set to Qt::Vertical , a widget is mapped to a row. Calling setCurrentIndex() will change the current column. The widget will be populates with the model's data from its mapped row and the column that currentIndex() points at.

Use Qt::Vertical for tabular data that looks like this:

1 2 3 4 5
Nokia Corporation and/or its subsidiary(-ies) Trolltech Pty Trolltech Inc Trolltech China Trolltech GmbH
Oslo Brisbane Silicon Valley Beijing Berlin
Changing the orientation clears all existing mappings.


removeMapping

public final void removeMapping(QWidget widget)
Removes the mapping for the given widget.

See also:
addMapping(), and clearMapping().


revert

public final void revert()
Repopulates all widgets with the current data of the model. All unsubmitted changes will be lost.

See also:
submit(), and setSubmitPolicy().


rootIndex

public final com.trolltech.qt.core.QModelIndex rootIndex()
Returns the current root index.

See also:
setRootIndex().


setCurrentModelIndex

public final void setCurrentModelIndex(com.trolltech.qt.core.QModelIndex index)
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:

    QDataWidgetMapper mapper = new QDataWidgetMapper();
    myTableView.selectionModel().currentRowChanged.connect(mapper, "setCurrentModelIndex(QModelIndex)");

See also:
currentIndex().


setItemDelegate

public final void setItemDelegate(QAbstractItemDelegate delegate)
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 QAbstractItemDelegate::setEditorData() and QAbstractItemDelegate::setModelData().

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


setModel

public final void setModel(QAbstractItemModel model)
Sets the current model to model. If another model was set, all mappings to that old model are cleared.

See also:
model().


setOrientation

public final void setOrientation(Qt.Orientation aOrientation)
This property holds the orientation of the model. If the orientation is Qt::Horizontal (the default), a widget is mapped to a column of a data model. The widget will be populated with the model's data from its mapped column and the row that currentIndex() points at.

Use Qt::Horizontal for tabular data that looks like this:

1 Nokia Corporation and/or its subsidiary(-ies) Oslo
2 Trolltech Pty Brisbane
3 Trolltech Inc Silicon Valley
4 Trolltech China Beijing
5 Trolltech GmbH Berlin
If the orientation is set to Qt::Vertical , a widget is mapped to a row. Calling setCurrentIndex() will change the current column. The widget will be populates with the model's data from its mapped row and the column that currentIndex() points at.

Use Qt::Vertical for tabular data that looks like this:

1 2 3 4 5
Nokia Corporation and/or its subsidiary(-ies) Trolltech Pty Trolltech Inc Trolltech China Trolltech GmbH
Oslo Brisbane Silicon Valley Beijing Berlin
Changing the orientation clears all existing mappings.


setRootIndex

public final void setRootIndex(com.trolltech.qt.core.QModelIndex index)
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().


setSubmitPolicy

public final void setSubmitPolicy(QDataWidgetMapper.SubmitPolicy policy)
This property holds the current submit policy. Changing the current submit policy will revert all widgets to the current data from the model.


submit

public final boolean submit()
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, QSqlQueryModel::lastError() can be used to retrieve the last error.

See also:
revert(), and setSubmitPolicy().


submitPolicy

public final QDataWidgetMapper.SubmitPolicy submitPolicy()
This property holds the current submit policy. Changing the current submit policy will revert all widgets to the current data from the model.


toFirst

public final void 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(), and setCurrentIndex().


toLast

public final void 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(), and setCurrentIndex().


toNext

public final void 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(), and setCurrentIndex().


toPrevious

public final void 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(), and setCurrentIndex().


setCurrentIndex

public void setCurrentIndex(int index)
This property holds the current row or column. The widgets are populated with with data from the row at index if the orientation is horizontal (the default), otherwise with data from the column at index.

See also:
setCurrentModelIndex(), toFirst(), toNext(), toPrevious(), and toLast().