QStyledItemDelegate class provides display and editing facilities for data items from a model. 更多...
| 头： | #include <QStyledItemDelegate> |
| qmake: | QT += widgets |
| Since: | Qt 4.4 |
| 继承： | QAbstractItemDelegate |
| QStyledItemDelegate (QObject * parent = Q_NULLPTR) | |
| ~QStyledItemDelegate () | |
| virtual QString | displayText (const QVariant & value , const QLocale & locale ) const |
| QItemEditorFactory * | itemEditorFactory () const |
| void | setItemEditorFactory (QItemEditorFactory * factory ) |
| virtual QWidget * | createEditor (QWidget * parent , const QStyleOptionViewItem & option , const QModelIndex & index ) const |
| virtual void | paint (QPainter * painter , const QStyleOptionViewItem & option , const QModelIndex & index ) const |
| virtual void | setEditorData (QWidget * editor , const QModelIndex & index ) const |
| virtual void | setModelData (QWidget * editor , QAbstractItemModel * model , const QModelIndex & index ) const |
| virtual QSize | sizeHint (const QStyleOptionViewItem & option , const QModelIndex & index ) const |
| virtual void | updateEditorGeometry (QWidget * editor , const QStyleOptionViewItem & option , const QModelIndex & index ) const |
| virtual void | initStyleOption (QStyleOptionViewItem * option , const QModelIndex & index ) const |
| virtual bool | editorEvent (QEvent * event , QAbstractItemModel * model , const QStyleOptionViewItem & option , const QModelIndex & index ) |
| virtual bool | eventFilter (QObject * editor , QEvent * event ) |
QStyledItemDelegate class provides display and editing facilities for data items from a model.
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.
QStyledItemDelegate 类是一种 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::BackgroundColorRole | QColor (obsolete; use Qt::BackgroundRole instead) |
| Qt::CheckStateRole | Qt::CheckState |
| Qt::DecorationRole | QIcon , QPixmap , QImage and QColor |
| Qt::DisplayRole | QString and types with a string representation |
| Qt::EditRole | 见 QItemEditorFactory for details |
| Qt::FontRole | QFont |
| Qt::SizeHintRole | QSize |
| Qt::TextAlignmentRole | Qt::Alignment |
| Qt::ForegroundRole | QBrush |
| Qt::TextColorRole | QColor (obsolete; use Qt::ForegroundRole instead) |
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 (). 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. The Color Editor Factory example shows how to create custom editors with a factory.
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.
When reimplementing 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:
Star Delegate 范例通过重实现这些方法创建编辑器。
从 Qt 4.4 起，有 2 个委托类： QItemDelegate and QStyledItemDelegate 。不管怎样，默认委托为 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 , 自旋框委托范例 , 星号委托范例 ，和 色彩编辑器工厂范例 .
构造项委托采用给定 parent .
销毁项委托。
[virtual]
QWidget
*QStyledItemDelegate::
createEditor
(
QWidget
*
parent
, const
QStyleOptionViewItem
&
option
, const
QModelIndex
&
index
) const
重实现自 QAbstractItemDelegate::createEditor ().
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 ().
[virtual]
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 ().
[virtual protected]
bool
QStyledItemDelegate::
editorEvent
(
QEvent
*
event
,
QAbstractItemModel
*
model
, const
QStyleOptionViewItem
&
option
, const
QModelIndex
&
index
)
重实现自 QAbstractItemDelegate::editorEvent ().
[virtual protected]
bool
QStyledItemDelegate::
eventFilter
(
QObject
*
editor
,
QEvent
*
event
)
重实现自 QObject::eventFilter ().
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:
若 editor 类型为 QTextEdit or QPlainTextEdit then Enter and Return keys are not handled.
In the case of Tab , Backtab , Enter and Return key press events, the editor 's data is comitted 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 previous 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 ().
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 ().
[virtual]
void
QStyledItemDelegate::
paint
(
QPainter
*
painter
, const
QStyleOptionViewItem
&
option
, const
QModelIndex
&
index
) const
重实现自 QAbstractItemDelegate::paint ().
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 .
[virtual]
void
QStyledItemDelegate::
setEditorData
(
QWidget
*
editor
, const
QModelIndex
&
index
) const
重实现自 QAbstractItemDelegate::setEditorData ().
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 ().
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 ().
[virtual]
void
QStyledItemDelegate::
setModelData
(
QWidget
*
editor
,
QAbstractItemModel
*
model
, const
QModelIndex
&
index
) const
重实现自 QAbstractItemDelegate::setModelData ().
获取数据从 editor 小部件并将它存储在指定 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 ().
[virtual]
QSize
QStyledItemDelegate::
sizeHint
(const
QStyleOptionViewItem
&
option
, const
QModelIndex
&
index
) const
重实现自 QAbstractItemDelegate::sizeHint ().
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 .
[virtual]
void
QStyledItemDelegate::
updateEditorGeometry
(
QWidget
*
editor
, const
QStyleOptionViewItem
&
option
, const
QModelIndex
&
index
) const
重实现自 QAbstractItemDelegate::updateEditorGeometry ().
更新 editor 为项指定通过 index 根据样式 option 给定。