Qt 4.8
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The QItemDelegate class provides display and editing facilities for data items from a model. More...
#include <qitemdelegate.h>
Public Functions | |
QWidget * | createEditor (QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const |
Returns the widget used to edit the item specified by index for editing. More... | |
bool | hasClipping () const |
QItemEditorFactory * | itemEditorFactory () const |
Returns the editor factory used by the item delegate. More... | |
void | paint (QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const |
Renders the delegate using the given painter and style option for the item specified by index. More... | |
QItemDelegate (QObject *parent=0) | |
Constructs an item delegate with the given parent. More... | |
void | setClipping (bool clip) |
void | 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. More... | |
void | setItemEditorFactory (QItemEditorFactory *factory) |
Sets the editor factory to be used by the item delegate to be the factory specified. More... | |
void | setModelData (QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const |
Gets data from the editor widget and stores it in the specified model at the item index. More... | |
QSize | sizeHint (const QStyleOptionViewItem &option, const QModelIndex &index) const |
Returns the size needed by the delegate to display the item specified by index, taking into account the style information provided by option. More... | |
void | updateEditorGeometry (QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const |
Updates the editor for the item specified by index according to the style option given. More... | |
~QItemDelegate () | |
Destroys the item delegate. More... | |
Public Functions inherited from QAbstractItemDelegate | |
QAbstractItemDelegate (QObject *parent=0) | |
Creates a new abstract item delegate with the given parent. More... | |
virtual | ~QAbstractItemDelegate () |
Destroys the abstract item delegate. More... | |
Public Functions inherited from QObject | |
bool | blockSignals (bool b) |
If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More... | |
const QObjectList & | children () const |
Returns a list of child objects. More... | |
bool | connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const |
bool | disconnect (const char *signal=0, const QObject *receiver=0, const char *member=0) |
bool | disconnect (const QObject *receiver, const char *member=0) |
void | dumpObjectInfo () |
Dumps information about signal connections, etc. More... | |
void | dumpObjectTree () |
Dumps a tree of children to the debug output. More... | |
QList< QByteArray > | dynamicPropertyNames () const |
Returns the names of all properties that were dynamically added to the object using setProperty(). More... | |
virtual bool | event (QEvent *) |
This virtual function receives events to an object and should return true if the event e was recognized and processed. More... | |
template<typename T > | |
T | findChild (const QString &aName=QString()) const |
Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More... | |
template<typename T > | |
QList< T > | findChildren (const QString &aName=QString()) const |
Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. More... | |
template<typename T > | |
QList< T > | findChildren (const QRegExp &re) const |
bool | inherits (const char *classname) const |
Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. More... | |
void | installEventFilter (QObject *) |
Installs an event filter filterObj on this object. More... | |
bool | isWidgetType () const |
Returns true if the object is a widget; otherwise returns false. More... | |
void | killTimer (int id) |
Kills the timer with timer identifier, id. More... | |
virtual const QMetaObject * | metaObject () const |
Returns a pointer to the meta-object of this object. More... | |
void | moveToThread (QThread *thread) |
Changes the thread affinity for this object and its children. More... | |
QString | objectName () const |
QObject * | parent () const |
Returns a pointer to the parent object. More... | |
QVariant | property (const char *name) const |
Returns the value of the object's name property. More... | |
Q_INVOKABLE | QObject (QObject *parent=0) |
Constructs an object with parent object parent. More... | |
void | removeEventFilter (QObject *) |
Removes an event filter object obj from this object. More... | |
void | setObjectName (const QString &name) |
void | setParent (QObject *) |
Makes the object a child of parent. More... | |
bool | setProperty (const char *name, const QVariant &value) |
Sets the value of the object's name property to value. More... | |
void | setUserData (uint id, QObjectUserData *data) |
bool | signalsBlocked () const |
Returns true if signals are blocked; otherwise returns false. More... | |
int | startTimer (int interval) |
Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More... | |
QThread * | thread () const |
Returns the thread in which the object lives. More... | |
QObjectUserData * | userData (uint id) const |
virtual | ~QObject () |
Destroys the object, deleting all its child objects. More... | |
Protected Functions | |
QRect | check (const QStyleOptionViewItem &option, const QRect &bounding, const QVariant &variant) const |
Note that on Mac, if /usr/include/AssertMacros. More... | |
QPixmap | decoration (const QStyleOptionViewItem &option, const QVariant &variant) const |
Returns the pixmap used to decorate the root of the item view. More... | |
void | doLayout (const QStyleOptionViewItem &option, QRect *checkRect, QRect *iconRect, QRect *textRect, bool hint) const |
void | drawBackground (QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const |
Renders the item background for the given index, using the given painter and style option. More... | |
virtual void | drawCheck (QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect, Qt::CheckState state) const |
Renders a check indicator within the rectangle specified by rect, using the given painter and style option, using the given state. More... | |
virtual void | drawDecoration (QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect, const QPixmap &pixmap) const |
Renders the decoration pixmap within the rectangle specified by rect using the given painter and style option. More... | |
virtual void | drawDisplay (QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect, const QString &text) const |
Renders the item view text within the rectangle specified by rect using the given painter and style option. More... | |
virtual void | drawFocus (QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect) const |
Renders the region within the rectangle specified by rect, indicating that it has the focus, using the given painter and style option. More... | |
bool | editorEvent (QEvent *event, QAbstractItemModel *model, const QStyleOptionViewItem &option, const QModelIndex &index) |
Reimplemented Function More... | |
bool | eventFilter (QObject *object, QEvent *event) |
Returns true if the given editor is a valid QWidget and the given event is handled; otherwise returns false. More... | |
QRect | rect (const QStyleOptionViewItem &option, const QModelIndex &index, int role) const |
QPixmap * | selected (const QPixmap &pixmap, const QPalette &palette, bool enabled) const |
Returns the selected version of the given pixmap using the given palette. More... | |
QStyleOptionViewItem | setOptions (const QModelIndex &index, const QStyleOptionViewItem &option) const |
QRect | textRectangle (QPainter *painter, const QRect &rect, const QFont &font, const QString &text) const |
Protected Functions inherited from QAbstractItemDelegate | |
QAbstractItemDelegate (QObjectPrivate &, QObject *parent=0) | |
Creates a new abstract item delegate with the given parent. More... | |
Protected Functions inherited from QObject | |
virtual void | childEvent (QChildEvent *) |
This event handler can be reimplemented in a subclass to receive child events. More... | |
virtual void | connectNotify (const char *signal) |
This virtual function is called when something has been connected to signal in this object. More... | |
virtual void | customEvent (QEvent *) |
This event handler can be reimplemented in a subclass to receive custom events. More... | |
virtual void | disconnectNotify (const char *signal) |
This virtual function is called when something has been disconnected from signal in this object. More... | |
QObject (QObjectPrivate &dd, QObject *parent=0) | |
int | receivers (const char *signal) const |
Returns the number of receivers connected to the signal. More... | |
QObject * | sender () const |
Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns 0. More... | |
int | senderSignalIndex () const |
virtual void | timerEvent (QTimerEvent *) |
This event handler can be reimplemented in a subclass to receive timer events for the object. More... | |
Properties | |
bool | clipping |
if the delegate should clip the paint events More... | |
Additional Inherited Members | |
Public Types inherited from QAbstractItemDelegate | |
enum | EndEditHint { NoHint, EditNextItem, EditPreviousItem, SubmitModelCache, RevertModelCache } |
This enum describes the different hints that the delegate can give to the model and view components to make editing data in a model a comfortable experience for the user. More... | |
Public Slots inherited from QAbstractItemDelegate | |
bool | helpEvent (QHelpEvent *event, QAbstractItemView *view, const QStyleOptionViewItem &option, const QModelIndex &index) |
Whenever a help event occurs, this function is called with the event view option and the index that corresponds to the item where the event occurs. More... | |
Public Slots inherited from QObject | |
void | deleteLater () |
Schedules this object for deletion. More... | |
Signals inherited from QAbstractItemDelegate | |
void | closeEditor (QWidget *editor, QAbstractItemDelegate::EndEditHint hint=NoHint) |
This signal is emitted when the user has finished editing an item using the specified editor. More... | |
void | commitData (QWidget *editor) |
This signal must be emitted when the editor widget has completed editing the data, and wants to write it back into the model. More... | |
void | sizeHintChanged (const QModelIndex &) |
This signal must be emitted when the sizeHint() of index changed. More... | |
Signals inherited from QObject | |
void | destroyed (QObject *=0) |
This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More... | |
Static Public Functions inherited from QAbstractItemDelegate | |
static QString | elidedText (const QFontMetrics &fontMetrics, int width, Qt::TextElideMode mode, const QString &text) |
Use QFontMetrics::elidedText() instead. More... | |
Static Public Functions inherited from QObject | |
static bool | connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection) |
Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More... | |
static bool | connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection) |
static bool | disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member) |
Disconnects signal in object sender from method in object receiver. More... | |
static bool | disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member) |
static uint | registerUserData () |
static QString | tr (const char *sourceText, const char *comment=0, int n=-1) |
static QString | trUtf8 (const char *sourceText, const char *comment=0, int n=-1) |
Static Public Variables inherited from QObject | |
static const QMetaObject | staticMetaObject |
This variable stores the meta-object for the class. More... | |
Protected Variables inherited from QObject | |
QScopedPointer< QObjectData > | d_ptr |
Static Protected Variables inherited from QObject | |
static const QMetaObject | staticQtMetaObject |
Related Functions inherited from QObject | |
T | qFindChildqFindChildren (const QObject *obj, const QString &name)() |
QList< T > | qFindChildrenqFindChildren (const QObject *obj, const QString &name)() |
QList< T > | qFindChildrenqFindChildren (const QObject *obj, const QRegExp ®Exp)() |
T * | qobject_cast (QObject *object) |
QObjectList | |
void * | qt_find_obj_child (QObject *parent, const char *type, const QString &name) |
Returns a pointer to the object named name that inherits type and with a given parent. More... | |
The QItemDelegate class provides display and editing facilities for data items from a model.
QItemDelegate can be used to provide custom display features and editor widgets for item views based on QAbstractItemView subclasses. Using a delegate for this purpose allows the display and editing mechanisms to be customized and developed independently from the model and view.
The QItemDelegate class is one of the Model/View Classes and is part of Qt's Model/View Programming{model/view framework}. Note that QStyledItemDelegate has taken over the job of drawing Qt's item views. We recommend the use of QStyledItemDelegate when creating new delegates.
When displaying items from a custom model in a standard view, it is often sufficient to simply ensure that the model returns appropriate data for each of the roles that determine the appearance of items in views. The default delegate used by Qt's standard views uses this role information to display items in most of the common forms expected by users. However, it is sometimes necessary to have even more control over the appearance of items than the default delegate can provide.
This class provides default implementations of the functions for painting item data in a view and editing data from item models. Default implementations of the paint() and sizeHint() virtual functions, defined in QAbstractItemDelegate, are provided to ensure that the delegate implements the correct basic behavior expected by views. You can reimplement these functions in subclasses to customize the appearance of items.
When editing data in an item view, QItemDelegate provides an editor widget, which is a widget that is placed on top of the view while editing takes place. 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 Qt::EditRole that is edited.
Only the standard editing functions for widget-based delegates are reimplemented here:
The closeEditor() signal indicates that the user has completed editing the data, and that the editor widget can be destroyed.
The default delegate used by the standard views supplied with Qt associates each standard role (defined by Qt::ItemDataRole) with certain data types. Models that return data in these types can influence the appearance of the delegate as described in the following table.
Role | Accepted Types
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Qt::AccessibleDescriptionRole | QString |
Qt::AccessibleTextRole | QString |
QColor (obsolete; use Qt::BackgroundRole instead)
QString and types with a string representation
See QItemEditorFactory for details
Qt::Alignment
QColor (obsolete; use Qt::ForegroundRole instead)
If the default delegate does not allow the level of customization that you need, either for display purposes or for editing data, it is possible to subclass QItemDelegate to implement the desired behavior.
When subclassing QItemDelegate to create a delegate that displays items using a custom renderer, it is important to ensure that the delegate can render items suitably for all the required states; e.g. selected, disabled, checked. The documentation for the paint() function contains some hints to show how this can be achieved.
You can provide custom editors by using a QItemEditorFactory. The Color Editor Factory Example shows how a custom editor can be made available to delegates with the default item editor factory. This way, there is no need to subclass QItemDelegate. An alternative is to reimplement createEditor(), setEditorData(), setModelData(), and updateEditorGeometry(). This process is described in the Spin Box Delegate Example.
Since Qt 4.4, there are two delegate classes: 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.
Definition at line 61 of file qitemdelegate.h.
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explicit |
Constructs an item delegate with the given parent.
Definition at line 319 of file qitemdelegate.cpp.
QItemDelegate::~QItemDelegate | ( | ) |
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protected |
Note that on Mac, if /usr/include/AssertMacros.
h is included prior to QItemDelegate, and the application is building in debug mode, the check(assertion) will conflict with QItemDelegate::check.
To avoid this problem, add
#ifdef check #undef check #endif
after including AssertMacros.h
Definition at line 1141 of file qitemdelegate.cpp.
Referenced by doLayout(), editorEvent(), paint(), rect(), and updateEditorGeometry().
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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.
Reimplemented from QAbstractItemDelegate.
Definition at line 528 of file qitemdelegate.cpp.
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protected |
Returns the pixmap used to decorate the root of the item view.
The style option controls the appearance of the root; the variant refers to the data associated with an item.
Definition at line 1014 of file qitemdelegate.cpp.
Referenced by doLayout(), paint(), and updateEditorGeometry().
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protected |
Code duplicated in QCommonStylePrivate::viewItemLayout
Definition at line 876 of file qitemdelegate.cpp.
Referenced by editorEvent(), paint(), sizeHint(), and updateEditorGeometry().
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protected |
Renders the item background for the given index, using the given painter and style option.
Definition at line 847 of file qitemdelegate.cpp.
Referenced by paint().
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protectedvirtual |
Renders a check indicator within the rectangle specified by rect, using the given painter and style option, using the given state.
Definition at line 808 of file qitemdelegate.cpp.
Referenced by paint().
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protectedvirtual |
Renders the decoration pixmap within the rectangle specified by rect using the given painter and style option.
Definition at line 753 of file qitemdelegate.cpp.
Referenced by paint().
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protectedvirtual |
Renders the item view text within the rectangle specified by rect using the given painter and style option.
Definition at line 669 of file qitemdelegate.cpp.
Referenced by paint().
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protectedvirtual |
Renders the region within the rectangle specified by rect, indicating that it has the focus, using the given painter and style option.
Definition at line 781 of file qitemdelegate.cpp.
Referenced by paint().
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protectedvirtual |
Reimplemented Function
Reimplemented from QAbstractItemDelegate.
Definition at line 1276 of file qitemdelegate.cpp.
Returns true if the given editor is a valid QWidget and the given event is handled; otherwise returns false.
The following key press events are handled by default:
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 is a Tab key press the view will open an editor on the next item in the view. Likewise, if the event is a 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.
Reimplemented from QObject.
Definition at line 1202 of file qitemdelegate.cpp.
bool QItemDelegate::hasClipping | ( | ) | const |
Definition at line 346 of file qitemdelegate.cpp.
Referenced by drawDisplay().
QItemEditorFactory * QItemDelegate::itemEditorFactory | ( | ) | const |
Returns the editor factory used by the item delegate.
If no editor factory is set, the function will return null.
Definition at line 645 of file qitemdelegate.cpp.
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virtual |
Renders the delegate using the given painter and style option for the item specified by index.
When reimplementing this function in a subclass, you should update the area held by the option's rect variable, using the option's state variable to determine the state of the item to be displayed, and adjust the way it is painted accordingly.
For example, a selected item may need to be displayed differently to unselected items, as shown in the following code:
...
After painting, you should ensure that the painter is returned to its 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.
Implements QAbstractItemDelegate.
Reimplemented in QCalendarDelegate, QComboBoxDelegate, and QCompleterItemDelegate.
Definition at line 416 of file qitemdelegate.cpp.
Referenced by QColumnViewDelegate::paint(), QCompleterItemDelegate::paint(), QComboBoxDelegate::paint(), QCalendarDelegate::paint(), and QCalendarDelegate::paintCell().
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protected |
Definition at line 1089 of file qitemdelegate.cpp.
Referenced by drawCheck(), drawDecoration(), drawFocus(), and sizeHint().
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protected |
Returns the selected version of the given pixmap using the given palette.
The enabled argument decides whether the normal or disabled highlight color of the palette is used.
Definition at line 1058 of file qitemdelegate.cpp.
Referenced by drawDecoration().
void QItemDelegate::setClipping | ( | bool | clip | ) |
Definition at line 352 of file qitemdelegate.cpp.
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virtual |
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 widget's Qt's Property System.
Reimplemented from QAbstractItemDelegate.
Definition at line 552 of file qitemdelegate.cpp.
void QItemDelegate::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.
Definition at line 658 of file qitemdelegate.cpp.
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virtual |
Gets data from the editor widget and stores it in the specified model at the item index.
The default implementation gets the value to be stored in the data model from the editor widget's Qt's Property System.
Reimplemented from QAbstractItemDelegate.
Definition at line 595 of file qitemdelegate.cpp.
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protected |
Definition at line 1328 of file qitemdelegate.cpp.
Referenced by paint().
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virtual |
Returns the size needed by the delegate to display the item specified by index, taking into account the style information provided by option.
When reimplementing this function, note that in case of text items, QItemDelegate adds a margin (i.e. 2 * QStyle::PM_FocusFrameHMargin) to the length of the text.
Implements QAbstractItemDelegate.
Reimplemented in QComboBoxDelegate.
Definition at line 505 of file qitemdelegate.cpp.
Referenced by QComboBoxDelegate::sizeHint().
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protected |
Definition at line 1159 of file qitemdelegate.cpp.
Referenced by paint(), rect(), and updateEditorGeometry().
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virtual |
Updates the editor for the item specified by index according to the style option given.
Reimplemented from QAbstractItemDelegate.
Definition at line 621 of file qitemdelegate.cpp.
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private |
if the delegate should clip the paint events
This property will set the paint clip to the size of the item. The default value is on. It is useful for cases such as when images are larger than the size of the item.
Definition at line 64 of file qitemdelegate.h.