QStyledItemDelegate 类

QStyledItemDelegate 类为来自模型的数据项，提供显示和编辑设施。更多...

头：	#include <QStyledItemDelegate>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Widgets) target_link_libraries(mytarget PRIVATE Qt6::Widgets)
qmake:	QT += widgets
继承：	QAbstractItemDelegate
继承者：	QSqlRelationalDelegate

所有成员列表，包括继承成员

公共函数

	QStyledItemDelegate (QObject * parent = nullptr)
virtual	~QStyledItemDelegate ()
virtual QString	displayText (const QVariant & value , const QLocale & locale ) const
QItemEditorFactory *	itemEditorFactory () const
void	setItemEditorFactory (QItemEditorFactory * factory )

重实现公共函数

virtual QWidget *	createEditor (QWidget * parent , const QStyleOptionViewItem & option , const QModelIndex & index ) const override
virtual void	paint (QPainter * painter , const QStyleOptionViewItem & option , const QModelIndex & index ) const override
virtual void	setEditorData (QWidget * editor , const QModelIndex & index ) const override
virtual void	setModelData (QWidget * editor , QAbstractItemModel * model , const QModelIndex & index ) const override
virtual QSize	sizeHint (const QStyleOptionViewItem & option , const QModelIndex & index ) const override
virtual void	updateEditorGeometry (QWidget * editor , const QStyleOptionViewItem & option , const QModelIndex & index ) const override

保护函数

virtual void

initStyleOption (QStyleOptionViewItem * option , const QModelIndex & index ) const

重实现保护函数

virtual bool	editorEvent (QEvent * event , QAbstractItemModel * model , const QStyleOptionViewItem & option , const QModelIndex & index ) override
virtual bool	eventFilter (QObject * editor , QEvent * event ) override

详细描述

When displaying data from models in Qt item views, e.g., a QTableView , the individual items are drawn by a delegate. Also, when an item is edited, it provides an editor widget, which is placed on top of the item view while editing takes place. QStyledItemDelegate is the default delegate for all Qt item views, and is installed upon them when they are created.

The QStyledItemDelegate class is one of the 模型/视图类且属于 Qt 的模型/视图框架 . The delegate allows the display and editing of items to be developed independently from the model and view.

The data of items in models are assigned an ItemDataRole ; each item can store a QVariant for each role. QStyledItemDelegate implements display and editing for the most common datatypes expected by users, including booleans, integers, and strings.

The data will be drawn differently depending on which role they have in the model. The following table describes the roles and the data types the delegate can handle for each of them. It is often sufficient to ensure that the model returns appropriate data for each of the roles to determine the appearance of items in views.

角色	接受类型
Qt::BackgroundRole	QBrush
Qt::CheckStateRole	Qt::CheckState
Qt::DecorationRole	QIcon , QPixmap , QImage and QColor
Qt::DisplayRole	QString 和按字符串表示的类型
Qt::EditRole	见 QItemEditorFactory 了解细节
Qt::FontRole	QFont
Qt::SizeHintRole	QSize
Qt::TextAlignmentRole	Qt::Alignment
Qt::ForegroundRole	QBrush

Editors are created with a QItemEditorFactory ; a default static instance provided by QItemEditorFactory is installed on all item delegates. You can set a custom factory using setItemEditorFactory () or set a new default factory with QItemEditorFactory::setDefaultFactory ().

QItemEditorFactory *editorFactory = new QItemEditorFactory;
QItemEditorCreatorBase *creator = new QStandardItemEditorCreator<MyFancyDateTimeEdit>();
editorFactory->registerEditor(QMetaType::QDateTime, creator);
QItemEditorFactory::setDefaultFactory(editorFactory);

After the new factory has been set, all standard item delegates will use it (i.e, also delegates that were created before the new default factory was set).

It is the data stored in the item model with the EditRole that is edited. See the QItemEditorFactory class for a more high-level introduction to item editor factories.

子类化 QStyledItemDelegate

If the delegate does not support painting of the data types you need or you want to customize the drawing of items, you need to subclass QStyledItemDelegate, and reimplement paint () and possibly sizeHint ()。 paint () function is called individually for each item, and with sizeHint (), you can specify the hint for each of them.

当重实现 paint (), one would typically handle the datatypes one would like to draw and use the superclass implementation for other types.

The painting of check box indicators are performed by the current style. The style also specifies the size and the bounding rectangles in which to draw the data for the different data roles. The bounding rectangle of the item itself is also calculated by the style. When drawing already supported datatypes, it is therefore a good idea to ask the style for these bounding rectangles. The QStyle class description describes this in more detail.

If you wish to change any of the bounding rectangles calculated by the style or the painting of check box indicators, you can subclass QStyle . Note, however, that the size of the items can also be affected by reimplementing sizeHint ().

It is possible for a custom delegate to provide editors without the use of an editor item factory. In this case, the following virtual functions must be reimplemented:

createEditor () returns the widget used to change data from the model and can be reimplemented to customize editing behavior.
setEditorData () provides the widget with data to manipulate.
updateEditorGeometry () ensures that the editor is displayed correctly with respect to the item view.
setModelData () returns updated data to the model.

The Star Delegate 范例通过重实现这些方法创建编辑器。

QStyledItemDelegate vs. QItemDelegate

从 Qt 4.4 起，有 2 个委托类： QItemDelegate and QStyledItemDelegate. However, the default delegate is QStyledItemDelegate. These two classes are independent alternatives to painting and providing editors for items in views. The difference between them is that QStyledItemDelegate uses the current style to paint its items. We therefore recommend using QStyledItemDelegate as the base class when implementing custom delegates or when working with Qt style sheets. The code required for either class should be equal unless the custom delegate needs to use the style for drawing.

If you wish to customize the painting of item views, you should implement a custom style. Please see the QStyle class documentation for details.

另请参阅 委托类 , QItemDelegate , QAbstractItemDelegate , QStyle ，和星号委托范例 .

成员函数文档编制

`[explicit]` QStyledItemDelegate:: QStyledItemDelegate ( QObject * parent = nullptr)

构造项委托采用给定 parent .

`[virtual noexcept]` QStyledItemDelegate:: ~QStyledItemDelegate ()

销毁项委托。

`[override virtual]` QWidget QStyledItemDelegate:: createEditor ( QWidget parent , const QStyleOptionViewItem & option , const QModelIndex & index ) const

重实现： QAbstractItemDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const .

Returns the widget used to edit the item specified by index for editing. The parent widget and style option are used to control how the editor widget appears.

另请参阅 QAbstractItemDelegate::createEditor ().

`[虚拟]` QString QStyledItemDelegate:: displayText (const QVariant & value , const QLocale & locale ) const

This function returns the string that the delegate will use to display the Qt::DisplayRole of the model in locale . value is the value of the Qt::DisplayRole provided by the model.

默认实现使用 QLocale::toString to convert value 成 QString .

This function is not called for empty model indices, i.e., indices for which the model returns an invalid QVariant .

另请参阅 QAbstractItemModel::data ().

`[override virtual protected]` bool QStyledItemDelegate:: editorEvent ( QEvent * event , QAbstractItemModel * model , const QStyleOptionViewItem & option , const QModelIndex & index )

重实现： QAbstractItemDelegate::editorEvent (QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index).

`[override virtual protected]` bool QStyledItemDelegate:: eventFilter ( QObject * editor , QEvent * event )

重实现： QObject::eventFilter (QObject *watched, QEvent *event).

返回 true 若给定 editor 有效 QWidget 和给定 event 有处理；否则返回 false . The following key press events are handled by default:

Tab
Backtab
Enter
返回
Esc

若 editor 类型为 QTextEdit or QPlainTextEdit then Tab , Backtab , Enter and 返回 keys are not handled.

In the case of Tab , Backtab , Enter and 返回 key press events, the editor 's data is committed to the model and the editor is closed. If the event 是 Tab key press the view will open an editor on the next item in the view. Likewise, if the event 是 Backtab key press the view will open an editor on the 上一 item in the view.

If the event is a Esc key press event, the editor is closed without committing its data.

另请参阅 commitData () 和 closeEditor ().

`[virtual protected]` void QStyledItemDelegate:: initStyleOption ( QStyleOptionViewItem * option , const QModelIndex & index ) const

初始化 option with the values using the index index 。此方法对子类是有用的，当需要 QStyleOptionViewItem ，但不希望自己填充所有信息。

另请参阅 QStyleOption::initFrom ().

QItemEditorFactory *QStyledItemDelegate:: itemEditorFactory () const

Returns the editor factory used by the item delegate. If no editor factory is set, the function will return null.

另请参阅 setItemEditorFactory ().

`[override virtual]` void QStyledItemDelegate:: paint ( QPainter * painter , const QStyleOptionViewItem & option , const QModelIndex & index ) const

重实现： QAbstractItemDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const .

Renders the delegate using the given painter 和样式 option 为项指定通过 index .

This function paints the item using the view's QStyle .

When reimplementing paint in a subclass. Use the initStyleOption () to set up the option in the same way as the QStyledItemDelegate .

Whenever possible, use the option while painting. Especially its rect variable to decide where to draw and its state to determine if it is enabled or selected.

After painting, you should ensure that the painter is returned to the state it was supplied in when this function was called. For example, it may be useful to call QPainter::save () before painting and QPainter::restore () afterwards.

另请参阅 QItemDelegate::paint (), QStyle::drawControl ()，和 QStyle::CE_ItemViewItem .

`[override virtual]` void QStyledItemDelegate:: setEditorData ( QWidget * editor , const QModelIndex & index ) const

重实现： QAbstractItemDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const .

Sets the data to be displayed and edited by the editor from the data model item specified by the model index .

The default implementation stores the data in the editor 小部件的用户特性 .

另请参阅 QMetaProperty::isUser ().

void QStyledItemDelegate:: setItemEditorFactory ( QItemEditorFactory * factory )

Sets the editor factory to be used by the item delegate to be the factory specified. If no editor factory is set, the item delegate will use the default editor factory.

另请参阅 itemEditorFactory ().

`[override virtual]` void QStyledItemDelegate:: setModelData ( QWidget * editor , QAbstractItemModel * model , const QModelIndex & index ) const

重实现： QAbstractItemDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const .

获取数据从 editor 小部件并把它存储在指定 model 在项 index .

The default implementation gets the value to be stored in the data model from the editor 小部件的用户特性 .

另请参阅 QMetaProperty::isUser ().

`[override virtual]` QSize QStyledItemDelegate:: sizeHint (const QStyleOptionViewItem & option , const QModelIndex & index ) const

重实现： QAbstractItemDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const .

返回委托要显示项所需的大小指定通过 index ，考虑样式信息提供通过 option .

此函数使用视图的 QStyle 以确定项大小。

另请参阅 QStyle::sizeFromContents () 和 QStyle::CT_ItemViewItem .

`[override virtual]` void QStyledItemDelegate:: updateEditorGeometry ( QWidget * editor , const QStyleOptionViewItem & option , const QModelIndex & index ) const

重实现： QAbstractItemDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const .

更新 editor 为项指定通过 index 根据样式 option 给定。

QStyledItemDelegate 类

公共函数

重实现公共函数

保护函数

重实现保护函数

详细描述

子类化 QStyledItemDelegate

QStyledItemDelegate vs. QItemDelegate

成员函数文档编制

[explicit] QStyledItemDelegate:: QStyledItemDelegate ( QObject * parent = nullptr)

[virtual noexcept] QStyledItemDelegate:: ~QStyledItemDelegate ()

[override virtual] QWidget *QStyledItemDelegate:: createEditor ( QWidget * parent , const QStyleOptionViewItem & option , const QModelIndex & index ) const

[虚拟] QString QStyledItemDelegate:: displayText (const QVariant & value , const QLocale & locale ) const

[override virtual protected] bool QStyledItemDelegate:: editorEvent ( QEvent * event , QAbstractItemModel * model , const QStyleOptionViewItem & option , const QModelIndex & index )

[override virtual protected] bool QStyledItemDelegate:: eventFilter ( QObject * editor , QEvent * event )

[virtual protected] void QStyledItemDelegate:: initStyleOption ( QStyleOptionViewItem * option , const QModelIndex & index ) const