class QTreeView

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

Inheritance diagram of PySide6.QtWidgets.QTreeView

Inherited by: QTreeWidget, QHelpContentWidget

Synopsis

Properties

Methods

Virtual methods

Slots

Signals

Note

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Detailed Description

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

../../_images/windows-treeview.png

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 QFileSystemModel and displayed as a tree:

    model = QFileSystemModel()
    model.setRootPath(QDir.currentPath())
if __name__ == "__main__":

    app = QApplication([])
    splitter = QSplitter()
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 tree views are constructed using the QHeaderView class and can be hidden using header()->hide(). Note that each header is configured with its stretchLastSection property set to true, ensuring that the view does not waste any of the space assigned to it for its header. If this value is set to true, this property will override the resize mode set on the last section in the header.

By default, all columns in a tree view are movable except the first. To disable movement of these columns, use QHeaderView ‘s setSectionsMovable() function. For more information about rearranging sections, see Moving Header Sections .

Key Bindings

QTreeView supports a set of key bindings that enable the user to navigate in the view and interact with the contents of items:

Key

Action

Up

Moves the cursor to the item in the same column on the previous row. If the parent of the current item has no more rows to navigate to, the cursor moves to the relevant item in the last row of the sibling that precedes the parent.

Down

Moves the cursor to the item in the same column on the next row. If the parent of the current item has no more rows to navigate to, the cursor moves to the relevant item in the first row of the sibling that follows the parent.

Left

Hides the children of the current item (if present) by collapsing a branch.

Minus

Same as Left.

Right

Reveals the children of the current item (if present) by expanding a branch.

Plus

Same as Right.

Asterisk

Expands the current item and all its children (if present).

PageUp

Moves the cursor up one page.

PageDown

Moves the cursor down one page.

Home

Moves the cursor to an item in the same column of the first row of the first top-level item in the model.

End

Moves the cursor to an item in the same column of the last row of the last top-level item in the model.

F2

In editable models, this opens the current item for editing. The Escape key can be used to cancel the editing process and revert any changes to the data displayed.

Improving Performance

It is possible to give the view hints about the data it is handling in order to improve its performance when displaying large numbers of items. One approach that can be taken for views that are intended to display items with equal heights is to set the uniformRowHeights property to true.

Note

Properties can be used directly when from __feature__ import true_property is used or via accessor functions otherwise.

property allColumnsShowFocusᅟ: bool

This property holds whether items should show keyboard focus using all columns.

If this property is true all columns will show focus, otherwise only one column will show focus.

The default is false.

Access functions:
property animatedᅟ: bool

This property holds whether animations are enabled.

If this property is true the treeview will animate expansion and collapsing of branches. If this property is false, the treeview will expand or collapse branches immediately without showing the animation.

By default, this property is false.

Access functions:
property autoExpandDelayᅟ: int

This property holds The delay time before items in a tree are opened during a drag and drop operation..

This property holds the amount of time in milliseconds that the user must wait over a node before that node will automatically open or close. If the time is set to less then 0 then it will not be activated.

By default, this property has a value of -1, meaning that auto-expansion is disabled.

Access functions:
property expandsOnDoubleClickᅟ: bool

This property holds whether the items can be expanded by double-clicking..

This property holds whether the user can expand and collapse items by double-clicking. The default value is true.

See also

itemsExpandable

Access functions:
property headerHiddenᅟ: bool

This property holds whether the header is shown or not..

If this property is true, the header is not shown otherwise it is. The default value is false.

See also

header()

Access functions:
property indentationᅟ: int

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

This property holds the indentation measured in pixels of the items for each level in the tree view. For top-level items, the indentation specifies the horizontal distance from the viewport edge to the items in the first column; for child items, it specifies their indentation from their parent items.

By default, the value of this property is style dependent. Thus, when the style changes, this property updates from it. Calling setIndentation() stops the updates, calling resetIndentation() will restore default behavior.

Access functions:
property itemsExpandableᅟ: bool

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

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

By default, this property is true.

Access functions:
property rootIsDecoratedᅟ: bool

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

Items with children are typically shown with controls to expand and collapse them, allowing their children to be shown or hidden. If this property is false, these controls are not shown for top-level items. This can be used to make a single level tree structure appear like a simple list of items.

By default, this property is true.

Access functions:
property sortingEnabledᅟ: bool

This property holds whether sorting is enabled.

If this property is true, sorting is enabled for the tree; if the property is false, sorting is not enabled. The default value is false.

Note

In order to avoid performance issues, it is recommended that sorting is enabled after inserting the items into the tree. Alternatively, you could also insert the items into a list before inserting the items into the tree.

See also

sortByColumn()

Access functions:
property uniformRowHeightsᅟ: 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 guaranteed that all items in the view has the same height. This enables the view to do some optimizations.

The height is obtained from the first item in the view. It is updated when the data changes on that item.

Note

If the editor size hint is bigger than the cell size hint, then the size hint of the editor will be used.

By default, this property is false.

Access functions:
property wordWrapᅟ: bool

This property holds the item text word-wrapping policy.

If this property is true then the item text is wrapped where necessary at word-breaks; otherwise it is not wrapped at all. This property is false by default.

Note that even if wrapping is enabled, the cell will not be expanded to fit all text. Ellipsis will be inserted according to the current textElideMode .

Access functions:
__init__([parent=None])
Parameters:

parent – QWidget

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

allColumnsShowFocus()
Return type:

bool

See also

setAllColumnsShowFocus()

Getter of property allColumnsShowFocusᅟ .

autoExpandDelay()
Return type:

int

See also

setAutoExpandDelay()

Getter of property autoExpandDelayᅟ .

collapse(index)
Parameters:

index – QModelIndex

Collapses the model item specified by the index.

See also

collapsed()

collapseAll()

Collapses all expanded items.

collapsed(index)
Parameters:

index – QModelIndex

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

columnAt(x)
Parameters:

x – int

Return type:

int

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

columnCountChanged(oldCount, newCount)
Parameters:

  • oldCount – int

  • newCount – int

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

columnMoved()

This slot is called whenever a column has been moved.

columnResized(column, oldSize, newSize)
Parameters:

  • column – int

  • oldSize – int

  • newSize – int

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.

See also

setColumnWidth()

columnViewportPosition(column)
Parameters:

column – int

Return type:

int

Returns the horizontal position of the column in the viewport.

columnWidth(column)
Parameters:

column – int

Return type:

int

Returns the width of the column.

drawBranches(painter, rect, index)
Parameters:

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.

drawRow(painter, options, index)
Parameters:

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

drawTree(painter, region)
Parameters:

Draws the part of the tree intersecting the given region using the specified painter.

See also

paintEvent()

expand(index)
Parameters:

index – QModelIndex

Expands the model item specified by the index.

See also

expanded()

expandAll()

Expands all expandable items.

Note

This function will not try to fetch more data.

Warning

If the model contains a large number of items, this function will take some time to execute.

See also

collapseAll() expand() collapse() setExpanded()

expandRecursively(index[, depth=-1])
Parameters:

Expands the item at the given index and all its children to the given depth. The depth is relative to the given index. A depth of -1 will expand all children, a depth of 0 will only expand the given index.

Note

This function will not try to fetch more data.

Warning

If the model contains a large number of items, this function will take some time to execute.

See also

expandAll()

expandToDepth(depth)
Parameters:

depth – int

Expands all expandable items to the given depth.

Note

This function will not try to fetch more data.

See also

expandAll() collapseAll() expand() collapse() setExpanded()

expanded(index)
Parameters:

index – QModelIndex

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

See also

setExpanded()

expandsOnDoubleClick()
Return type:

bool

See also

setExpandsOnDoubleClick()

Getter of property expandsOnDoubleClickᅟ .

header()
Return type:

QHeaderView

Returns the header for the tree view.

hideColumn(column)
Parameters:

column – int

Hides the column given.

Note

This function should only be called after the model has been initialized, as the view needs to know the number of columns in order to hide column.

See also

showColumn() setColumnHidden()

indentation()
Return type:

int

See also

setIndentation()

Getter of property indentationᅟ .

indexAbove(index)
Parameters:

index – QModelIndex

Return type:

QModelIndex

Returns the model index of the item above index.

indexBelow(index)
Parameters:

index – QModelIndex

Return type:

QModelIndex

Returns the model index of the item below index.

indexRowSizeHint(index)
Parameters:

index – QModelIndex

Return type:

int

Returns the size hint for the row indicated by index.

See also

sizeHintForColumn() uniformRowHeights()

isAnimated()
Return type:

bool

Getter of property animatedᅟ .

isColumnHidden(column)
Parameters:

column – int

Return type:

bool

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

isExpanded(index)
Parameters:

index – QModelIndex

Return type:

bool

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

isFirstColumnSpanned(row, parent)
Parameters:
Return type:

bool

Returns true if the item in first column in the given row of the parent is spanning all the columns; otherwise returns false.

isHeaderHidden()
Return type:

bool

Getter of property headerHiddenᅟ .

isRowHidden(row, parent)
Parameters:
Return type:

bool

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

isSortingEnabled()
Return type:

bool

Getter of property sortingEnabledᅟ .

itemsExpandable()
Return type:

bool

See also

setItemsExpandable()

Getter of property itemsExpandableᅟ .

reexpand()
resetIndentation()

Reset function of property indentationᅟ .

resizeColumnToContents(column)
Parameters:

column – int

Resizes the column given to the size of its contents.

rootIsDecorated()
Return type:

bool

See also

setRootIsDecorated()

Getter of property rootIsDecoratedᅟ .

rowHeight(index)
Parameters:

index – QModelIndex

Return type:

int

Returns the height of the row indicated by the given index.

rowsRemoved(parent, first, last)
Parameters:

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

setAllColumnsShowFocus(enable)
Parameters:

enable – bool

See also

allColumnsShowFocus()

Setter of property allColumnsShowFocusᅟ .

setAnimated(enable)
Parameters:

enable – bool

See also

isAnimated()

Setter of property animatedᅟ .

setAutoExpandDelay(delay)
Parameters:

delay – int

See also

autoExpandDelay()

Setter of property autoExpandDelayᅟ .

setColumnHidden(column, hide)
Parameters:

  • column – int

  • hide – bool

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

setColumnWidth(column, width)
Parameters:

  • column – int

  • width – int

Sets the width of the given column to the width specified.

setExpanded(index, expand)
Parameters:

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

setExpandsOnDoubleClick(enable)
Parameters:

enable – bool

See also

expandsOnDoubleClick()

Setter of property expandsOnDoubleClickᅟ .

setFirstColumnSpanned(row, parent, span)
Parameters:

If span is true the item in the first column in the row with the given parent is set to span all columns, otherwise all items on the row are shown.

setHeader(header)
Parameters:

header – QHeaderView

Sets the header for the tree view, to the given header.

The view takes ownership over the given header and deletes it when a new header is set.

See also

headerData()

setHeaderHidden(hide)
Parameters:

hide – bool

See also

isHeaderHidden()

Setter of property headerHiddenᅟ .

setIndentation(i)
Parameters:

i – int

See also

indentation()

Setter of property indentationᅟ .

setItemsExpandable(enable)
Parameters:

enable – bool

See also

itemsExpandable()

Setter of property itemsExpandableᅟ .

setRootIsDecorated(show)
Parameters:

show – bool

See also

rootIsDecorated()

Setter of property rootIsDecoratedᅟ .

setRowHidden(row, parent, hide)
Parameters:

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

setSortingEnabled(enable)
Parameters:

enable – bool

See also

isSortingEnabled()

Setter of property sortingEnabledᅟ .

setTreePosition(logicalIndex)
Parameters:

logicalIndex – int

This specifies that the tree structure should be placed at logical index index. If set to -1 then the tree will always follow visual index 0.

setUniformRowHeights(uniform)
Parameters:

uniform – bool

See also

uniformRowHeights()

Setter of property uniformRowHeightsᅟ .

setWordWrap(on)
Parameters:

on – bool

See also

wordWrap()

Setter of property wordWrapᅟ .

showColumn(column)
Parameters:

column – int

Shows the given column in the tree view.

sortByColumn(column, order)
Parameters:

Sorts the model by the values in the given column and order.

column may be -1, in which case no sort indicator will be shown and the model will return to its natural, unsorted order. Note that not all models support this and may even crash in this case.

See also

sortingEnabled

treePosition()
Return type:

int

Return the logical index the tree is set on. If the return value is -1 then the tree is placed on the visual index 0.

uniformRowHeights()
Return type:

bool

See also

setUniformRowHeights()

Getter of property uniformRowHeightsᅟ .

wordWrap()
Return type:

bool

See also

setWordWrap()

Getter of property wordWrapᅟ .