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## com.trolltech.qt.gui
Class QDataWidgetMapper

    java.lang.Object
      com.trolltech.qt.QSignalEmitter
          com.trolltech.qt.QtJambiObject
              com.trolltech.qt.core.QObject
                  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 | Trolltech ASA | 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 `Trolltech ASA` 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.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9`

Field Summary
`QSignalEmitter.Signal1` | `currentIndexChanged` This signal is emitted after the current index has changed and all widgets were populated with new data.

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.
`static QDataWidgetMapper` | `fromNativePointer(QNativePointer nativePointer)` This method returns the QDataWidgetMapper instance pointed to by `nativePointer`.
`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.
`QModelIndex` | `rootIndex()` Returns the current root index.
`void` | `setCurrentIndex(int index)` This property holds the current row or column.
`void` | `setCurrentModelIndex(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(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 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 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 `QLineEdit` `nameLineEdit`, and the second is mapped to the `QSpinBox` `ageSpinBox`:

          QDataWidgetMapper mapper = new QDataWidgetMapper();
          mapper.setModel(model);
          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()`, 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 | Trolltech ASA | 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
  Trolltech ASA | 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 QModelIndex rootIndex()

  Returns the current root index.

See also:
  `setRootIndex()`.

### setCurrentModelIndex

    public final void setCurrentModelIndex(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 | Trolltech ASA | 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
  Trolltech ASA | 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(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()`.

### fromNativePointer

    public static QDataWidgetMapper fromNativePointer(QNativePointer nativePointer)

  This method returns the QDataWidgetMapper instance pointed to by `nativePointer`.

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