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# QTreeView Class Reference

The QTreeView class provides a default model/view implementation of a tree view. More...

    #include <QTreeView>

Part of the QtGui module.

Inherits QAbstractItemView.

Inherited by QTreeWidget.

- List of all members, including inherited members

### Properties

- indentation : int
- itemsExpandable : bool
- rootIsDecorated : bool
- uniformRowHeights : bool

- 10 properties inherited from QAbstractItemView
- 2 properties inherited from QAbstractScrollArea
- 6 properties inherited from QFrame
- 52 properties inherited from QWidget
- 1 property inherited from QObject

### Public Functions

- QTreeView ( QWidget * parent = 0 )
- ~QTreeView ()
- int columnAt ( int x ) const
- int columnViewportPosition ( int column ) const
- int columnWidth ( int column ) const
- virtual void doItemsLayout ()
- QHeaderView * header () const
- int indentation () const
- QModelIndex indexAbove ( const QModelIndex & index ) const
- QModelIndex indexBelow ( const QModelIndex & index ) const
- bool isColumnHidden ( int column ) const
- bool isExpanded ( const QModelIndex & index ) const
- bool isRowHidden ( int row, const QModelIndex & parent ) const
- bool itemsExpandable () const
- bool rootIsDecorated () const
- virtual void scrollTo ( const QModelIndex & index, ScrollHint hint = EnsureVisible )
- void setColumnHidden ( int column, bool hide )
- void setExpanded ( const QModelIndex & index, bool expanded )
- void setHeader ( QHeaderView * header )
- void setIndentation ( int i )
- void setItemsExpandable ( bool enable )
- void setRootIsDecorated ( bool show )
- void setRowHidden ( int row, const QModelIndex & parent, bool hide )
- void setUniformRowHeights ( bool uniform )
- bool uniformRowHeights () const
- virtual QRect visualRect ( const QModelIndex & index ) const

- 37 public functions inherited from QAbstractItemView
- 8 public functions inherited from QAbstractScrollArea
- 13 public functions inherited from QFrame
- 183 public functions inherited from QWidget
- 28 public functions inherited from QObject
- 10 public functions inherited from QPaintDevice

### Public Slots

- void collapse ( const QModelIndex & index )
- void expand ( const QModelIndex & index )
- void hideColumn ( int column )
- void resizeColumnToContents ( int column )
- virtual void selectAll ()
- void showColumn ( int column )
- void sortByColumn ( int column )

- 6 public slots inherited from QAbstractItemView
- 17 public slots inherited from QWidget
- 1 public slot inherited from QObject

### Signals

- void collapsed ( const QModelIndex & index )
- void expanded ( const QModelIndex & index )

- 6 signals inherited from QAbstractItemView
- 1 signal inherited from QWidget
- 1 signal inherited from QObject

### Protected Functions

- virtual void drawBranches ( QPainter * painter, const QRect & rect, const QModelIndex & index ) const
- virtual void drawRow ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const
- virtual int horizontalOffset () const
- int indexRowSizeHint ( const QModelIndex & index ) const
- virtual QModelIndex moveCursor ( CursorAction cursorAction, Qt::KeyboardModifiers modifiers )
- virtual void rowsAboutToBeRemoved ( const QModelIndex & parent, int start, int end )
- virtual void rowsInserted ( const QModelIndex & parent, int start, int end )
- virtual void scrollContentsBy ( int dx, int dy )
- virtual void setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags command )
- virtual int sizeHintForColumn ( int column ) const
- virtual int verticalOffset () const
- virtual QRegion visualRegionForSelection ( const QItemSelection & selection ) const

- 35 protected functions inherited from QAbstractItemView
- 17 protected functions inherited from QAbstractScrollArea
- 39 protected functions inherited from QWidget
- 7 protected functions inherited from QObject

### Protected Slots

- void columnCountChanged ( int oldCount, int newCount )
- void columnMoved ()
- void columnResized ( int column, int oldSize, int newSize )

- 8 protected slots inherited from QAbstractItemView

### Additional Inherited Members

- 2 static public members inherited from QFrame
- 4 static public members inherited from QWidget
- 4 static public members inherited from QObject

## Detailed Description

The QTreeView class provides a default model/view implementation of a tree view.

A QTreeView implements a tree representation of items from a model. This class is used to provide standard hierarchical lists that were previously provided by the `QListView` class, but using the more flexible approach provided by Qt's model/view architecture.

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

QTreeView implements the interfaces defined by the QAbstractItemView class to allow it to display data provided by models derived from the QAbstractItemModel class.

It is simple to construct a tree view displaying data from a model. In the following example, the contents of a directory are supplied by a QDirModel and displayed as a tree:

            QDirModel *model = new QDirModel;
            QTreeView *tree = new QTreeView(splitter);
            tree->setModel(model);

The model/view architecture ensures that the contents of the tree view are updated as the model changes.

Items that have children can be in an expanded (children are visible) or collapsed (children are hidden) state. When this state changes a collapsed() or expanded() signal is emitted with the model index of the relevant item.

The amount of indentation used to indicate levels of hierarchy is controlled by the indentation property.

Headers in a tree view are constructed using the QHeaderView class.

See also Model/View Programming, QAbstractItemModel, and QAbstractItemView.

## Property Documentation

### indentation : int

This property holds indentation of the items in the tree view.

This property holds the indentation of the items for each level in the tree view.

Access functions:

- int indentation () const
- void setIndentation ( int i )

### itemsExpandable : bool

This property holds whether the items are expandable by the user.

This property holds whether the user can expand and collapse items interactively.

Access functions:

- bool itemsExpandable () const
- void setItemsExpandable ( bool enable )

### rootIsDecorated : bool

This property holds whether to show controls for expanding and collapsing items.

This property holds whether root items are displayed with controls for expanding and collapsing them.

Access functions:

- bool rootIsDecorated () const
- void setRootIsDecorated ( bool show )

### uniformRowHeights : bool

This property holds whether all items in the treeview have the same height.

This property should only be set to true if it is guarantied that all items in the view has the same height. This enables the view to do some optimizations.

Access functions:

- bool uniformRowHeights () const
- void setUniformRowHeights ( bool uniform )

## Member Function Documentation

### QTreeView::QTreeView ( QWidget * parent = 0 )

Constructs a table view with a parent to represent a model's data. Use setModel() to set the model.

See also QAbstractItemModel.

### QTreeView::~QTreeView ()

Destroys the tree view.

### void QTreeView::collapse ( const QModelIndex & index ) `[slot]`

Collapses the model item specified by the index.

### void QTreeView::collapsed ( const QModelIndex & index ) `[signal]`

This signal is emitted when the item specified by index is collapsed.

### int QTreeView::columnAt ( int x ) const

Returns the column in the tree view whose header covers the x coordinate given.

### void QTreeView::columnCountChanged ( int oldCount, int newCount ) `[protected slot]`

Informs the tree view that the number of columns in the tree view has changed from oldCount to newCount.

### void QTreeView::columnMoved () `[protected slot]`

This slot is called whenever a column has been moved.

### void QTreeView::columnResized ( int column, int oldSize, int newSize ) `[protected slot]`

This function is called whenever column's size is changed in the header. oldSize and newSize give the previous size and the new size in pixels.

### int QTreeView::columnViewportPosition ( int column ) const

Returns the horizontal position of the column in the viewport.

### int QTreeView::columnWidth ( int column ) const

Returns the width of the column.

See also resizeColumnToContents().

### void QTreeView::doItemsLayout () `[virtual]`

Lays out the items in the tree view.

Reimplemented from QAbstractItemView.

### void QTreeView::drawBranches ( QPainter * painter, const QRect & rect, const QModelIndex & index ) const `[virtual protected]`

Draws the branches in the tree view on the same row as the model item index, using the painter given. The branches are drawn in the rectangle specified by rect.

### void QTreeView::drawRow ( QPainter * painter, const QStyleOptionViewItem & option, const QModelIndex & index ) const `[virtual protected]`

Draws the row in the tree view that contains the model item index, using the painter given. The option control how the item is displayed.

See also QStyleOptionViewItem.

### void QTreeView::expand ( const QModelIndex & index ) `[slot]`

Expands the model item specified by the index.

### void QTreeView::expanded ( const QModelIndex & index ) `[signal]`

This signal is emitted when the item specified by index is expanded.

### QHeaderView * QTreeView::header () const

Returns the header for the tree view.

### void QTreeView::hideColumn ( int column ) `[slot]`

Hides the column given.

See also showColumn().

### int QTreeView::horizontalOffset () const `[virtual protected]`

Returns the horizontal offset.

Reimplemented from QAbstractItemView.

### QModelIndex QTreeView::indexAbove ( const QModelIndex & index ) const

Returns the model index of the item above index.

### QModelIndex QTreeView::indexBelow ( const QModelIndex & index ) const

Returns the model index of the item below index.

### int QTreeView::indexRowSizeHint ( const QModelIndex & index ) const `[protected]`

Returns the size hint for the row indicated by index.

See also sizeHintForColumn().

### bool QTreeView::isColumnHidden ( int column ) const

Returns true if the column is hidden; otherwise returns false.

See also hideColumn().

### bool QTreeView::isExpanded ( const QModelIndex & index ) const

Returns true if the model item index is expanded; otherwise returns false.

### bool QTreeView::isRowHidden ( int row, const QModelIndex & parent ) const

Returns true if the item in the given row of the parent is hidden; otherwise returns false.

See also setRowHidden().

### QModelIndex QTreeView::moveCursor ( CursorAction cursorAction, Qt::KeyboardModifiers modifiers ) `[virtual protected]`

Move the cursor in the way described by cursorAction, using the information provided by the button modifiers.

Reimplemented from QAbstractItemView.

### void QTreeView::resizeColumnToContents ( int column ) `[slot]`

Resizes the column given to the size of its contents.

### void QTreeView::rowsAboutToBeRemoved ( const QModelIndex & parent, int start, int end ) `[virtual protected]`

Informs the view that the rows from the start row to the end row inclusive have been removed from the given parent model item.

Reimplemented from QAbstractItemView.

### void QTreeView::rowsInserted ( const QModelIndex & parent, int start, int end ) `[virtual protected]`

Informs the view that the rows from the start row to the end row inclusive have been inserted into the parent model item.

Reimplemented from QAbstractItemView.

### void QTreeView::scrollContentsBy ( int dx, int dy ) `[virtual protected]`

Scrolls the contents of the tree view by (dx, dy).

Reimplemented from QAbstractScrollArea.

### void QTreeView::scrollTo ( const QModelIndex & index, ScrollHint hint = EnsureVisible ) `[virtual]`

Scroll the contents of the tree view until the given model item index is visible. The hint parameter specifies more precisely where the item should be located after the operation.

Reimplemented from QAbstractItemView.

### void QTreeView::selectAll () `[virtual slot]`

Selects all the items in the underlying model.

Reimplemented from QAbstractItemView.

### void QTreeView::setColumnHidden ( int column, bool hide )

If hide is true the column is hidden, otherwise the column is shown.

### void QTreeView::setExpanded ( const QModelIndex & index, bool expanded )

Sets the item referred to by index to either collapse or expanded, depending on the value of expanded.

See also expanded().

### void QTreeView::setHeader ( QHeaderView * header )

Sets the header for the tree view.

### void QTreeView::setRowHidden ( int row, const QModelIndex & parent, bool hide )

If hide is true the row with the given parent is hidden, otherwise the row is shown.

See also isRowHidden().

### void QTreeView::setSelection ( const QRect & rect, QItemSelectionModel::SelectionFlags command ) `[virtual protected]`

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

Reimplemented from QAbstractItemView.

See also selectionCommand().

### void QTreeView::showColumn ( int column ) `[slot]`

Shows the given column in the tree view.

See also hideColumn().

### int QTreeView::sizeHintForColumn ( int column ) const `[virtual protected]`

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

If you need to set the width of a given column to a fixed value, call QHeaderView::resizeSection() on the view's header.

If you reimplement this function in a subclass, note that the value you return is only used when resizeColumnToContents() is called. In that case, if a larger column width is required by either the view's header or the item delegate, that width will be used instead.

Reimplemented from QAbstractItemView.

See also QWidget::sizeHint and header().

### void QTreeView::sortByColumn ( int column ) `[slot]`

Sorts the model by the values in the given column.

### int QTreeView::verticalOffset () const `[virtual protected]`

Returns the vertical offset of the items in the tree view.

Reimplemented from QAbstractItemView.

### QRect QTreeView::visualRect ( const QModelIndex & index ) const `[virtual]`

Returns the rectangle on the viewport occupied by the item at index. If the index is not visible or explicitly hidden, the returned rectangle is invalid.

Reimplemented from QAbstractItemView.

### QRegion QTreeView::visualRegionForSelection ( const QItemSelection & selection ) const `[virtual protected]`

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

Reimplemented from QAbstractItemView.