PySide.QtGui.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 PySide.QtGui.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. PySide.QtGui.QStyledItemDelegate is the default delegate for all Qt item views, and is installed upon them when they are created.
PySide.QtGui.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 Qt.ItemDataRole ; each item can store a PySide.QtCore.QVariant for each role. PySide.QtGui.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.
| Role | Accepted Types |
| Qt.BackgroundRole | PySide.QtGui.QBrush |
| Qt.BackgroundColorRole | PySide.QtGui.QColor (obsolete; use Qt.BackgroundRole instead) |
| Qt.CheckStateRole | Qt.CheckState |
| Qt.DecorationRole | PySide.QtGui.QIcon , PySide.QtGui.QPixmap , PySide.QtGui.QImage and PySide.QtGui.QColor |
| Qt.DisplayRole | PySide.QtCore.QString and types with a string representation |
| Qt.EditRole | 见 PySide.QtGui.QItemEditorFactory for details |
| Qt.FontRole | PySide.QtGui.QFont |
| Qt.SizeHintRole | PySide.QtCore.QSize |
| Qt.TextAlignmentRole | Qt.Alignment |
| Qt.ForegroundRole | PySide.QtGui.QBrush |
| Qt.TextColorRole | PySide.QtGui.QColor (obsolete; use Qt.ForegroundRole instead) |
Editors are created with a PySide.QtGui.QItemEditorFactory ; a default static instance provided by PySide.QtGui.QItemEditorFactory is installed on all item delegates. You can set a custom factory using PySide.QtGui.QStyledItemDelegate.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 PySide.QtGui.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 PySide.QtGui.QStyledItemDelegate , and reimplement PySide.QtGui.QStyledItemDelegate.paint() and possibly PySide.QtGui.QStyledItemDelegate.sizeHint() 。 PySide.QtGui.QStyledItemDelegate.paint() function is called individually for each item, and with PySide.QtGui.QStyledItemDelegate.sizeHint() , you can specify the hint for each of them.
When reimplementing PySide.QtGui.QStyledItemDelegate.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 PySide.QtGui.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 PySide.QtGui.QStyle . Note, however, that the size of the items can also be affected by reimplementing PySide.QtGui.QStyledItemDelegate.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 example creates editors by reimplementing these methods.
Since Qt 4.4, there are two delegate classes: PySide.QtGui.QItemDelegate and PySide.QtGui.QStyledItemDelegate . However, the default delegate is PySide.QtGui.QStyledItemDelegate . These two classes are independent alternatives to painting and providing editors for items in views. The difference between them is that PySide.QtGui.QStyledItemDelegate uses the current style to paint its items. We therefore recommend using PySide.QtGui.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 PySide.QtGui.QStyle class documentation for details.
另请参阅
委托类 PySide.QtGui.QItemDelegate PySide.QtGui.QAbstractItemDelegate PySide.QtGui.QStyle 自旋框委托范例 星号委托范例 色彩编辑器工厂范例
| 参数： | parent – PySide.QtCore.QObject |
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构造项委托采用给定 parent .
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| 返回类型： |
unicode |
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.
The default implementation uses the QLocale::toString to convert value 成 PySide.QtCore.QString .
This function is not called for empty model indices, i.e., indices for which the model returns an invalid PySide.QtCore.QVariant .
另请参阅
QAbstractItemModel.data()
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初始化 option with the values using the index index 。此方法对子类是有用的，当需要 PySide.QtGui.QStyleOptionViewItem , but don't want to fill in all the information themselves. This function will check the version of the PySide.QtGui.QStyleOptionViewItem and fill in the additional values for a PySide.QtGui.QStyleOptionViewItemV2 , PySide.QtGui.QStyleOptionViewItemV3 and PySide.QtGui.QStyleOptionViewItemV4 .
| 返回类型： | PySide.QtGui.QItemEditorFactory |
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Returns the editor factory used by the item delegate. If no editor factory is set, the function will return null.
| 参数： | factory – PySide.QtGui.QItemEditorFactory |
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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.
