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QAbstractItemView Class Reference

The QAbstractItemView class provides the basic functionality for item view classes. More...

#include <QAbstractItemView>

Part of the QtGui module.

Inherits QAbstractScrollArea.

Inherited by QHeaderView, QListView, QTableView, and QTreeView.

Public Types

Properties

Public Functions

Public Slots

Signals

Protected Types

Protected Functions

Protected Slots

Additional Inherited Members


Detailed Description

The QAbstractItemView class provides the basic functionality for item view classes.

QAbstractItemView class is the base class for every standard view that uses a QAbstractItemModel. QAbstractItemView is an abstract class and cannot itself be instantiated. It provides a standard interface for interoperating with models through the signals and slots mechanism, enabling subclasses to be kept up-to-date with changes to their models. This class provides standard support for keyboard and mouse navigation, viewport scrolling, item editing, and selections.

The QAbstractItemView class is one of the Model/View Classes and is part of Qt's model/view framework.

The view classes that inherit QAbstractItemView only need to implement their own view-specific functionality, such as drawing items, returning the geometry of items, finding items, etc.

QAbstractItemView provides common slots such as edit() and setCurrentIndex(). Many protected slots are also provided, including dataChanged(), rowsInserted(), rowsAboutToBeRemoved(), columnsInserted(), columnsRemoved(), selectionChanged(), and currentChanged().

The root item is returned by rootIndex(), and the current item by currentIndex(). To make sure that an item is visible use scrollTo().

Some of QAbstractItemView's functions are concerned with scrolling, for example setHorizontalFactor() and setVerticalFactor(). Several other functions are concerned with selection control; for example setSelectionMode(), and setSelectionBehavior(). This class provides a default selection model to work with (selectionModel()), but this can be replaced by using setSelectionModel() with an instance of QItemSelectionModel.

For complete control over the display and editing of items you can specify a delegate with setItemDelegate().

QAbstractItemView provides a lot of protected functions. Some are concerned with editing, for example, edit(), and commitData(), whilst others are keyboard and mouse event handlers.

See also Model/View Programming and QAbstractItemModel.


Member Type Documentation

enum QAbstractItemView::CursorAction

This enum describes the different ways to navigate between items,

ConstantValueDescription
QAbstractItemView::MoveUp0Move to the item above the current item.
QAbstractItemView::MoveDown1Move to the item below the current item.
QAbstractItemView::MoveLeft2Move to the item left of the current item.
QAbstractItemView::MoveRight3Move to the item right of the current item.
QAbstractItemView::MoveHome4Move to the top-left corner item.
QAbstractItemView::MoveEnd5Move to the bottom-right corner item.
QAbstractItemView::MovePageUp6Move one page up above the current item.
QAbstractItemView::MovePageDown7Move one page down below the current item.
QAbstractItemView::MoveNext8Move to the item after the current item.
QAbstractItemView::MovePrevious9Move to the item before the current item.

See also moveCursor().

enum QAbstractItemView::EditTrigger
flags QAbstractItemView::EditTriggers

This enum describes actions which will initiate item editing.

ConstantValueDescription
QAbstractItemView::NoEditTriggers0No editing possible.
QAbstractItemView::CurrentChanged1Editing start whenever current item changes.
QAbstractItemView::DoubleClicked2Editing starts when an item is double clicked.
QAbstractItemView::SelectedClicked4Editing starts when clicking on an already selected item.
QAbstractItemView::EditKeyPressed8Editing starts when an edit key has been pressed over an item.
QAbstractItemView::AnyKeyPressed16Editing starts when any key is pressed over an item.
QAbstractItemView::AllEditTriggers31Editing starts for all above actions.

The EditTriggers type is a typedef for QFlags<EditTrigger>. It stores an OR combination of EditTrigger values.

enum QAbstractItemView::ScrollHint

ConstantValueDescription
QAbstractItemView::EnsureVisible0Scroll to ensure that the item is visible.
QAbstractItemView::PositionAtTop1Scroll to position the item at the top of the viewport.
QAbstractItemView::PositionAtBottom2Scroll to position the item at the bottom of the viewport.

enum QAbstractItemView::SelectionBehavior

ConstantValueDescription
QAbstractItemView::SelectItems0Selecting single items.
QAbstractItemView::SelectRows1Selecting only rows.
QAbstractItemView::SelectColumns2Selecting only columns.

enum QAbstractItemView::SelectionMode

This enum indicates how the view responds to user selections:

ConstantValueDescription
QAbstractItemView::SingleSelection1When the user selects an item, any already-selected item becomes unselected, and the user cannot unselect the selected item.
QAbstractItemView::MultiSelection2When the user selects an item in the usual way, the selection status of that item is toggled and the other items are left alone.
QAbstractItemView::ExtendedSelection3When the user selects an item in the usual way, the selection is cleared and the new item selected. However, if the user presses the Ctrl key when clicking on an item, the clicked item gets toggled and all other items are left untouched. If the user presses the Shift key while clicking on an item, all items between the current item and the clicked item are selected or unselected, depending on the state of the clicked item. Multiple items can be selected by dragging the mouse over them.
QAbstractItemView::NoSelection0Items cannot be selected.

In other words, SingleSelection is a real single-selection list view, MultiSelection a real multi-selection list view, ExtendedSelection is a list view in which users can select multiple items, but usually want to select either just one or a range of contiguous items, and NoSelection is a list view where the user can navigate without selecting items.

enum QAbstractItemView::State

Describes the different states the view can be in. This is usually only interesting when reimplementing your own view.

ConstantValueDescription
QAbstractItemView::NoState0The is the default state.
QAbstractItemView::DraggingState1The user is dragging items.
QAbstractItemView::DragSelectingState2The user is selecting items.
QAbstractItemView::EditingState3The user is editing an item in a widget editor.
QAbstractItemView::ExpandingState4The user is opening a branch of items.
QAbstractItemView::CollapsingState5The user is closing a branch of items.

Property Documentation

alternatingRowColors : bool

This property holds whether to draw the background using alternating colors.

If this property is true, the item background will be drawn using alternating colors, otherwise the background will be drawn using the QPalette::Base color.

Access functions:

autoScroll : bool

This property holds whether autoscrolling in drag move events is enabled.

If this property is set to true (the default), the QAbstractItemView automatically scrolls the contents of the view if the user drags within 16 pixels of the viewport edge. This only works if the viewport accepts drops. Autoscroll is switched off by setting this property to false.

Access functions:

dragEnabled : bool

This property holds whether the view supports dragging of its own items.

Access functions:

editTriggers : EditTriggers

This property holds which actions will initiate item editing.

This property is a selection of flags defined by EditTrigger, combined using the OR operator. The view will only initiate the editing of an item if the action performed is set in this property.

Access functions:

iconSize : QSize

This property holds the size of items.

Setting this property when the view is visible will cause the items to be laid out again.

Access functions:

selectionBehavior : SelectionBehavior

This property holds which selection behavior the view uses.

This property holds whether selections are done in terms of single items, rows or columns.

Access functions:

See also SelectionMode and SelectionBehavior.

selectionMode : SelectionMode

This property holds which selection mode the view operates in.

This property controls whether the user can select one or many items and, in many-item selections, whether the selection must be a continuous range of items.

Access functions:

See also SelectionMode and SelectionBehavior.

showDropIndicator : bool

This property holds whether the drop indicator is shown when dragging items and dropping.

Access functions:

tabKeyNavigation : bool

This property holds whether item navigation with tab and backtab is enabled.

Access functions:

textElideMode : Qt::TextElideMode

This property holds the the position of the "..." in elided text.

Access functions:


Member Function Documentation

QAbstractItemView::QAbstractItemView ( QWidget * parent = 0 )

Constructs an abstract item view with the given parent.

QAbstractItemView::~QAbstractItemView ()

Destroys the view.

void QAbstractItemView::activated ( const QModelIndex & index )   [signal]

This signal is emitted when the item specified by index is activated by the user (e.g., by single- or double-clicking the item, depending on the platform).

See also clicked(), doubleClicked(), entered(), and pressed().

void QAbstractItemView::clearSelection ()   [slot]

Clears all selected items.

void QAbstractItemView::clicked ( const QModelIndex & index )   [signal]

This signal is emitted when a mouse button is clicked. The item the mouse was clicked on is specified by index (which may be invalid if the mouse was not clicked on an item).

See also activated(), doubleClicked(), entered(), and pressed().

void QAbstractItemView::closeEditor ( QWidget * editor, QAbstractItemDelegate::EndEditHint hint )   [virtual protected slot]

Closes the given editor, and releases it. The hint is used to specify how the view should respond to the end of the editing operation. For example, the hint may indicate that the next item in the view should be opened for editing.

See also edit().

void QAbstractItemView::closePersistentEditor ( const QModelIndex & index )

Closes the persistent editor for the item at the given index.

void QAbstractItemView::commitData ( QWidget * editor )   [virtual protected slot]

Commit the data in the editor to the model.

See also closeEditor().

void QAbstractItemView::currentChanged ( const QModelIndex & current, const QModelIndex & previous )   [virtual protected slot]

This slot is called when a new item becomes the current item. The previous current item is specified by the previous index, and the new item by the current index.

If you want to know about changes to items see the dataChanged() signal.

QModelIndex QAbstractItemView::currentIndex () const

Returns the model index of the current item.

See also setCurrentIndex().

void QAbstractItemView::dataChanged ( const QModelIndex & topLeft, const QModelIndex & bottomRight )   [virtual protected slot]

This slot is called when items are changed in the model. The changed items are those from topLeft to bottomRight inclusive. If just one item is changed topLeft == bottomRight.

void QAbstractItemView::doubleClicked ( const QModelIndex & index )   [signal]

This signal is emitted when a mouse button is double-clicked. The item the mouse was double-clicked on is specified by index (which may be invalid if the mouse was not double-clicked on an item).

void QAbstractItemView::dragEnterEvent ( QDragEnterEvent * e )   [virtual protected]

This function is called when drag enter event e occurs. If the drag is over a valid dropping place (e.g. over an item that accepts drops), the event is accepted.

Reimplemented from QWidget.

See also dropEvent() and startDrag().

void QAbstractItemView::dragLeaveEvent ( QDragLeaveEvent * event )   [virtual protected]

This function is called when the item being dragged leaves the view. The event describes the state of the drag and drop operation.

Reimplemented from QWidget.

void QAbstractItemView::dragMoveEvent ( QDragMoveEvent * e )   [virtual protected]

This function is called when drag move event e occurs. It can cause the view to scroll, for example if the user drags a selection to view's right or bottom edge.

Reimplemented from QWidget.

See also dropEvent() and startDrag().

void QAbstractItemView::dropEvent ( QDropEvent * e )   [virtual protected]

This function is called when drop event e occurs. If there's a valid item under the mouse pointer when the drop occurs, the drop is accepted.

Reimplemented from QWidget.

See also startDrag().

void QAbstractItemView::edit ( const QModelIndex & index )   [slot]

Starts editing the item item at index if it is editable.

bool QAbstractItemView::edit ( const QModelIndex & index, EditTrigger trigger, QEvent * event )   [virtual protected]

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

Starts editing the item at index, creating an editor if necessary, and returns true if the view's State is now EditingState; otherwise returns false.

The action that caused the editing process is described by trigger, and the associated event is specified by event.

See also closeEditor().

void QAbstractItemView::editorDestroyed ( QObject * editor )   [virtual protected slot]

Remove the editor editor from the map.

void QAbstractItemView::entered ( const QModelIndex & index )   [signal]

This signal is emitted when the mouse cursor enters the item specified by index.

See also viewportEntered(), activated(), clicked(), doubleClicked(), and pressed().

void QAbstractItemView::focusInEvent ( QFocusEvent * e )   [virtual protected]

This function is called when focus event e occurs and is a focus in event.

Reimplemented from QWidget.

void QAbstractItemView::focusOutEvent ( QFocusEvent * e )   [virtual protected]

This function is called when focus event e occurs and is a focus out event.

Reimplemented from QWidget.

int QAbstractItemView::horizontalOffset () const   [pure virtual protected]

Returns the horizontal offset of the view.

In the base class this is a pure virtual function.

int QAbstractItemView::horizontalStepsPerItem () const   [protected]

Returns the horizontal scrollbar's steps per item.

See also setHorizontalStepsPerItem() and verticalStepsPerItem().

QModelIndex QAbstractItemView::indexAt ( const QPoint & p ) const   [pure virtual]

Returns the model index of the item at point p.

In the base class this is a pure virtual function.

bool QAbstractItemView::isIndexHidden ( const QModelIndex & index ) const   [pure virtual protected]

Returns true if the item refered to by the given index is hidden, otherwise returns false.

In the base class this is a pure virtual function.

QAbstractItemDelegate * QAbstractItemView::itemDelegate () const

Returns the item delegate used by this view and model. This is either one set with setItemDelegate(), or the default one.

See also setItemDelegate().

void QAbstractItemView::keyPressEvent ( QKeyEvent * e )   [virtual protected]

This function is called when a key event e occurs. It handles basic cursor movement, e.g. Up, Down, Left, Right, Home, PageUp, and PageDown, and emits the returnPressed(), spacePressed(), and deletePressed() signals is the associated key is pressed. This function is where editing is initiated by key press, e.g. if F2 is pressed.

Reimplemented from QWidget.

See also edit().

void QAbstractItemView::keyboardSearch ( const QString & search )   [virtual]

Moves to and selects the item best matching the string search. If no item is found nothing happens.

QAbstractItemModel * QAbstractItemView::model () const

Returns the model that this view is presenting.

void QAbstractItemView::mouseDoubleClickEvent ( QMouseEvent * e )   [virtual protected]

This function is called when a mouse double-click event e occurs. If the double-click is on a valid item it emits the doubleClicked() signal and calls edit() on the item.

Reimplemented from QWidget.

void QAbstractItemView::mouseMoveEvent ( QMouseEvent * e )   [virtual protected]

This function is called when a mouse move event e occurs. If a selection is in progress and new items are moved over the selection is extended; if a drag is in progress it is continued.

Reimplemented from QWidget.

void QAbstractItemView::mousePressEvent ( QMouseEvent * e )   [virtual protected]

This function is called when a mouse event e occurs. If a valid item is pressed on it is made into the current item. This function emits the pressed() signal.

Reimplemented from QWidget.

void QAbstractItemView::mouseReleaseEvent ( QMouseEvent * e )   [virtual protected]

This function is called when a mouse release event e occurs. It will emit the clicked() signal if an item was being pressed.

Reimplemented from QWidget.

QModelIndex QAbstractItemView::moveCursor ( CursorAction cursorAction, Qt::KeyboardModifiers modifiers )   [pure virtual protected]

Moves the cursor in the view according to the given cursorAction and keyboard modifiers specified by modifiers.

void QAbstractItemView::openPersistentEditor ( const QModelIndex & index )

Opens a persistent editor on the item at the given index. If no editor exists, the delegate will create a new editor.

void QAbstractItemView::pressed ( const QModelIndex & index )   [signal]

This signal is emitted when a mouse button is pressed. The item the mouse was pressed on is specified by index (which may be invalid if the mouse was not pressed on an item).

See also activated(), clicked(), doubleClicked(), and entered().

void QAbstractItemView::reset ()   [virtual slot]

Reset the internal state of the view.

void QAbstractItemView::resizeEvent ( QResizeEvent * e )   [virtual protected]

This function is called when a resize event e occurs.

Reimplemented from QWidget.

QModelIndex QAbstractItemView::rootIndex () const

Returns the model index of the model's root item. The root item is the parent item to the views toplevel items. The root can be invalid.

See also setRootIndex().

void QAbstractItemView::rowsAboutToBeRemoved ( const QModelIndex & parent, int start, int end )   [virtual protected slot]

This slot is called when rows are about to be removed. The deleted rows are those under the given parent from start to end inclusive. The base class implementation does nothing.

See also rowsInserted().

void QAbstractItemView::rowsInserted ( const QModelIndex & parent, int start, int end )   [virtual protected slot]

This slot is called when rows are inserted. The new rows are those under the given parent from start to end inclusive. The base class implementation calls fetchMore() on the model to check for more data.

See also rowsAboutToBeRemoved().

void QAbstractItemView::scrollDirtyRegion ( int dx, int dy )   [protected]

Prepares the view for scrolling by (dx,a dy) pixels by moving the dirty regions in the opposite direction. You only need to call this function if you are implementing a scrolling viewport in your view subclass.

If you implement scrollContentsBy() in a subclass of QAbstractItemView, call this function before you call QWidget::scroll() on the viewport. Alternatively, just call update().

See also scrollContentsBy().

void QAbstractItemView::scrollTo ( const QModelIndex & index, ScrollHint hint = EnsureVisible )   [pure virtual]

Scrolls the view if necessary to ensure that the item at index is visible. The view will try to position the item according to the given hint.

In the base class this is a pure virtual function.

void QAbstractItemView::selectAll ()   [virtual slot]

Selects all non-hidden items.

QModelIndexList QAbstractItemView::selectedIndexes () const   [virtual protected]

This convenience function returns a list of all selected and non-hidden item indexes in the view. The list contains no duplicates, and is not sorted.

The default implementation does nothing.

void QAbstractItemView::selectionChanged ( const QItemSelection & selected, const QItemSelection & deselected )   [virtual protected slot]

This slot is called when the selection is changed. The previous selection (which may be empty), is specified by deselected, and the new selection by selected.

QItemSelectionModel::SelectionFlags QAbstractItemView::selectionCommand ( const QModelIndex & index, const QEvent * event = 0 ) const   [virtual protected]

Returns the SelectionFlags to be used when updating a selection with to include the index specified. The event is a user input event, such as a mouse or keyboard event.

Reimplement this function to define your own selection behavior.

QItemSelectionModel * QAbstractItemView::selectionModel () const

Returns the current selection.

See also setSelectionModel() and clearSelection().

void QAbstractItemView::setCurrentIndex ( const QModelIndex & index )   [slot]

Sets the current item to be the itm at index.

See also currentIndex().

void QAbstractItemView::setHorizontalStepsPerItem ( int steps )   [protected]

Sets the horizontal scrollbar's steps per item to steps.

This is the number of steps used by the horizontal scrollbar to represent the width of an item.

See also horizontalStepsPerItem() and setVerticalStepsPerItem().

void QAbstractItemView::setItemDelegate ( QAbstractItemDelegate * delegate )

Sets the item delegate for this view and its model to delegate. This is useful if you want complete control over the editing and display of items.

See also itemDelegate().

void QAbstractItemView::setModel ( QAbstractItemModel * model )   [virtual]

Sets the model for the view to present.

void QAbstractItemView::setRootIndex ( const QModelIndex & index )   [virtual slot]

Sets the root item to the item at index.

See also rootIndex().

void QAbstractItemView::setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags flags )   [pure virtual protected]

Applies the selection flags to the items in or touched by the rectangle, rect.

See also selectionCommand().

void QAbstractItemView::setSelectionModel ( QItemSelectionModel * selectionModel )   [virtual]

Sets the current selection to the given selectionModel.

See also selectionModel() and clearSelection().

void QAbstractItemView::setState ( State state )   [protected]

Sets the item view's state to the given state

See also state().

void QAbstractItemView::setVerticalStepsPerItem ( int steps )   [protected]

Sets the vertical scrollbar's steps per item to steps.

This is the number of steps used by the vertical scrollbar to represent the height of an item.

See also verticalStepsPerItem() and setHorizontalStepsPerItem().

int QAbstractItemView::sizeHintForColumn ( int column ) const   [virtual]

Returns the width size hint for the specified column or -1 if there is no model.

QSize QAbstractItemView::sizeHintForIndex ( const QModelIndex & index ) const

Returns the size hint for the item with the specified index or an invalid size for invalid indexes.

int QAbstractItemView::sizeHintForRow ( int row ) const   [virtual]

Returns the height size hint for the specified row or -1 if there is no model.

void QAbstractItemView::startDrag ( Qt::DropActions supportedActions )   [virtual protected]

Starts a drag by calling drag->start() using the given supportedActions.

State QAbstractItemView::state () const   [protected]

Returns the item view's state.

See also setState().

void QAbstractItemView::timerEvent ( QTimerEvent * e )   [virtual protected]

This function is called when a timer event e occurs.

Reimplemented from QObject.

int QAbstractItemView::verticalOffset () const   [pure virtual protected]

Returns the vertical offset of the view.

In the base class this is a pure virtual function.

int QAbstractItemView::verticalStepsPerItem () const   [protected]

Returns the vertical scrollbar's steps per item.

See also setVerticalStepsPerItem() and horizontalStepsPerItem().

QStyleOptionViewItem QAbstractItemView::viewOptions () const   [virtual protected]

Returns QStyleOptionViewItem structure populated with the view's palette, font, state, alignments etc.

void QAbstractItemView::viewportEntered ()   [signal]

This signal is emitted when the mouse cursor enters the viewport.

See also entered().

bool QAbstractItemView::viewportEvent ( QEvent * event )   [virtual protected]

This function is used to handle tool tips, status tips, and What's This? mode, if the given event is a QEvent::ToolTip, a QEvent::WhatsThis, or a QEvent::StatusTip. It passes all other events on to its base class viewportEvent() handler.

Reimplemented from QAbstractScrollArea.

QRect QAbstractItemView::visualRect ( const QModelIndex & index ) const   [pure virtual]

Returns the rectangle on the viewport occupied by the item at index.

In the base class this is a pure virtual function.

QRegion QAbstractItemView::visualRegionForSelection ( const QItemSelection & selection ) const   [pure virtual protected]

Returns the region from the viewport of the items in the given selection.


Copyright © 2005 Trolltech Trademarks
Qt 4.0.0-rc1