The QDataWidgetMapper class provides mapping between a section of a data model to widgets. 更多...
| 头： | #include <QDataWidgetMapper> |
| qmake: | QT += widgets |
| Since: | Qt 4.2 |
| 继承： | QObject |
| enum | SubmitPolicy { AutoSubmit, ManualSubmit } |
| QDataWidgetMapper (QObject * parent = nullptr) | |
| virtual | ~QDataWidgetMapper () |
| void | addMapping (QWidget * widget , int section ) |
| void | addMapping (QWidget * widget , int section , const QByteArray & propertyName ) |
| void | clearMapping () |
| int | currentIndex () const |
| QAbstractItemDelegate * | itemDelegate () const |
| QByteArray | mappedPropertyName (QWidget * widget ) const |
| int | mappedSection (QWidget * widget ) const |
| QWidget * | mappedWidgetAt (int section ) const |
| QAbstractItemModel * | model () const |
| Qt::Orientation | orientation () const |
| void | removeMapping (QWidget * widget ) |
| QModelIndex | rootIndex () const |
| void | setItemDelegate (QAbstractItemDelegate * delegate ) |
| void | setModel (QAbstractItemModel * model ) |
| void | setOrientation (Qt::Orientation aOrientation ) |
| void | setRootIndex (const QModelIndex & index ) |
| void | setSubmitPolicy (QDataWidgetMapper::SubmitPolicy policy ) |
| QDataWidgetMapper::SubmitPolicy | submitPolicy () const |
| void | revert () |
| virtual void | setCurrentIndex (int index ) |
| void | setCurrentModelIndex (const QModelIndex & index ) |
| bool | submit () |
| void | toFirst () |
| void | toLast () |
| void | toNext () |
| void | toPrevious () |
| void | currentIndexChanged (int index ) |
| const QMetaObject | staticMetaObject |
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 用户特性 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
:
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
显示值
1
,
myLineEdit
displays
Qt Norway
and
myCountryChooser
displays
Oslo
. The navigational functions
toFirst
(),
toNext
(),
toPrevious
(),
toLast
() 和
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
() 被调用。
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.
注意， 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.
另请参阅 QAbstractItemModel and QAbstractItemDelegate .
This enum describes the possible submit policies a QDataWidgetMapper 支持。
| 常量 | 值 | 描述 |
|---|---|---|
QDataWidgetMapper::AutoSubmit
|
0
|
Whenever a widget loses focus, the widget's current value is set to the item model. |
QDataWidgetMapper::ManualSubmit
|
1
|
The model is not updated until submit () 被调用。 |
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 .
访问函数：
| int | currentIndex () const |
| virtual void | setCurrentIndex (int index ) |
通知程序信号：
| void | currentIndexChanged (int index ) |
另请参阅 setCurrentModelIndex (), toFirst (), toNext (), toPrevious ()，和 toLast ().
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.
使用 Qt::Horizontal for tabular data that looks like this:
| 1 | Qt Norway | Oslo |
| 2 | Qt Australia | Brisbane |
| 3 | Qt USA | Silicon Valley |
| 4 | Qt China | Beijing |
| 5 | Qt Germany | 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.
使用 Qt::Vertical for tabular data that looks like this:
| 1 | 2 | 3 | 4 | 5 |
| Qt Norway | Qt Australia | Qt USA | Qt China | Qt Germany |
| Oslo | Brisbane | Silicon Valley | Beijing | Berlin |
Changing the orientation clears all existing mappings.
访问函数：
| Qt::Orientation | orientation () const |
| void | setOrientation (Qt::Orientation aOrientation ) |
This property holds the current submit policy
Changing the current submit policy will revert all widgets to the current data from the model.
访问函数：
| QDataWidgetMapper::SubmitPolicy | submitPolicy () const |
| void | setSubmitPolicy (QDataWidgetMapper::SubmitPolicy policy ) |
构造新的
QDataWidgetMapper
with parent object
parent
. By default, the orientation is horizontal and the submit policy is
AutoSubmit
.
另请参阅 setOrientation () 和 setSubmitPolicy ().
[虚拟]
QDataWidgetMapper::
~QDataWidgetMapper
()
销毁对象。
Adds a mapping between a widget 和 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(myModel); mapper->addMapping(nameLineEdit, 0); mapper->addMapping(ageSpinBox, 1);
注意事项：
另请参阅 removeMapping (), mappedSection ()，和 clearMapping ().
Essentially the same as addMapping (), but adds the possibility to specify the property to use specifying propertyName .
该函数在 Qt 4.3 引入。
另请参阅 addMapping ().
Clears all mappings.
另请参阅 addMapping () 和 removeMapping ().
[signal]
void
QDataWidgetMapper::
currentIndexChanged
(
int
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.
注意： 通知程序信号对于特性 currentIndex .
另请参阅 currentIndex () 和 setCurrentIndex ().
Returns the current item delegate.
另请参阅 setItemDelegate ().
Returns the name of the property that is used when mapping data to the given widget .
该函数在 Qt 4.3 引入。
另请参阅 mappedSection (), addMapping ()，和 removeMapping ().
Returns the section the widget is mapped to or -1 if the widget is not mapped.
另请参阅 addMapping () 和 removeMapping ().
Returns the widget that is mapped at section , or 0 if no widget is mapped at that section.
另请参阅 addMapping () 和 removeMapping ().
Returns the current model.
另请参阅 setModel ().
Removes the mapping for the given widget .
另请参阅 addMapping () 和 clearMapping ().
[slot]
void
QDataWidgetMapper::
revert
()
Repopulates all widgets with the current data of the model. All unsubmitted changes will be lost.
另请参阅 submit () 和 setSubmitPolicy ().
Returns the current root index.
另请参阅 setRootIndex ().
[slot]
void
QDataWidgetMapper::
setCurrentModelIndex
(const
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 .
调用 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
命名
myTableView
changes:
QDataWidgetMapper *mapper = new QDataWidgetMapper(); connect(myTableView->selectionModel(), SIGNAL(currentRowChanged(QModelIndex,QModelIndex)), mapper, SLOT(setCurrentModelIndex(QModelIndex)));
另请参阅 currentIndex ().
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 () 和 QAbstractItemDelegate::setModelData ().
The delegate also decides when to apply data and when to change the editor, using QAbstractItemDelegate::commitData () 和 QAbstractItemDelegate::closeEditor ().
警告： 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() 信号，且试图访问、修改或关闭已关闭的编辑器。
另请参阅 itemDelegate ().
Sets the current model to model . If another model was set, all mappings to that old model are cleared.
另请参阅 model ().
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.
另请参阅 rootIndex ().
[slot]
bool
QDataWidgetMapper::
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.
返回
true
if all the values were submitted, otherwise false.
Note: For database models, QSqlQueryModel::lastError () can be used to retrieve the last error.
另请参阅 revert () 和 setSubmitPolicy ().
[slot]
void
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.
这相当于调用
setCurrentIndex(0)
.
另请参阅 toLast () 和 setCurrentIndex ().
[slot]
void
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.
调用 setCurrentIndex () internally.
另请参阅 toFirst () 和 setCurrentIndex ().
[slot]
void
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.
调用 setCurrentIndex () internally. Does nothing if there is no next row in the model.
另请参阅 toPrevious () 和 setCurrentIndex ().
[slot]
void
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.
调用 setCurrentIndex () internally. Does nothing if there is no previous row in the model.
另请参阅 toNext () 和 setCurrentIndex ().