QTreeView

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

Inheritance diagram of PySide2.QtWidgets.QTreeView

Inherited by: QHelpContentWidget, QTreeWidget

Synopsis

Functions

Virtual functions

Slots

Signals

Detailed Description

../../_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())

tree =  QTreeView()
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.

class PySide2.QtWidgets.QTreeView([parent=None])

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

See also

QAbstractItemModel

PySide2.QtWidgets.QTreeView.allColumnsShowFocus()
Return type

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.

PySide2.QtWidgets.QTreeView.autoExpandDelay()
Return type

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.

PySide2.QtWidgets.QTreeView.collapse(index)
Parameters

indexPySide2.QtCore.QModelIndex

Collapses the model item specified by the index .

See also

collapsed()

PySide2.QtWidgets.QTreeView.collapseAll()

Collapses all expanded items.

PySide2.QtWidgets.QTreeView.collapsed(index)
Parameters

indexPySide2.QtCore.QModelIndex

PySide2.QtWidgets.QTreeView.columnAt(x)
Parameters

x – int

Return type

int

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

PySide2.QtWidgets.QTreeView.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 .

PySide2.QtWidgets.QTreeView.columnMoved()

This slot is called whenever a column has been moved.

PySide2.QtWidgets.QTreeView.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()

PySide2.QtWidgets.QTreeView.columnViewportPosition(column)
Parameters

column – int

Return type

int

Returns the horizontal position of the column in the viewport.

PySide2.QtWidgets.QTreeView.columnWidth(column)
Parameters

column – int

Return type

int

Returns the width of the column .

PySide2.QtWidgets.QTreeView.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 .

PySide2.QtWidgets.QTreeView.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.

PySide2.QtWidgets.QTreeView.drawTree(painter, region)
Parameters

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

See also

paintEvent()

PySide2.QtWidgets.QTreeView.expand(index)
Parameters

indexPySide2.QtCore.QModelIndex

Expands the model item specified by the index .

See also

expanded()

PySide2.QtWidgets.QTreeView.expandAll()

Expands all expandable items.

Warning

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

PySide2.QtWidgets.QTreeView.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 .

Warning

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

See also

expandAll()

PySide2.QtWidgets.QTreeView.expandToDepth(depth)
Parameters

depth – int

Expands all expandable items to the given depth .

PySide2.QtWidgets.QTreeView.expanded(index)
Parameters

indexPySide2.QtCore.QModelIndex

PySide2.QtWidgets.QTreeView.expandsOnDoubleClick()
Return type

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

PySide2.QtWidgets.QTreeView.header()
Return type

PySide2.QtWidgets.QHeaderView

Returns the header for the tree view.

See also

setHeader() headerData()

PySide2.QtWidgets.QTreeView.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 .

PySide2.QtWidgets.QTreeView.indentation()
Return type

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 stops the updates, calling will restore default behavior.

PySide2.QtWidgets.QTreeView.indexAbove(index)
Parameters

indexPySide2.QtCore.QModelIndex

Return type

PySide2.QtCore.QModelIndex

Returns the model index of the item above index .

PySide2.QtWidgets.QTreeView.indexBelow(index)
Parameters

indexPySide2.QtCore.QModelIndex

Return type

PySide2.QtCore.QModelIndex

Returns the model index of the item below index .

PySide2.QtWidgets.QTreeView.indexRowSizeHint(index)
Parameters

indexPySide2.QtCore.QModelIndex

Return type

int

Returns the size hint for the row indicated by index .

See also

sizeHintForColumn() uniformRowHeights()

PySide2.QtWidgets.QTreeView.isAnimated()
Return type

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 .

PySide2.QtWidgets.QTreeView.isColumnHidden(column)
Parameters

column – int

Return type

bool

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

PySide2.QtWidgets.QTreeView.isExpanded(index)
Parameters

indexPySide2.QtCore.QModelIndex

Return type

bool

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

PySide2.QtWidgets.QTreeView.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 .

PySide2.QtWidgets.QTreeView.isHeaderHidden()
Return type

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()

PySide2.QtWidgets.QTreeView.isRowHidden(row, parent)
Parameters
Return type

bool

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

PySide2.QtWidgets.QTreeView.isSortingEnabled()
Return type

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()

PySide2.QtWidgets.QTreeView.itemsExpandable()
Return type

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 .

PySide2.QtWidgets.QTreeView.reexpand()
PySide2.QtWidgets.QTreeView.resetIndentation()

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 stops the updates, calling will restore default behavior.

PySide2.QtWidgets.QTreeView.resizeColumnToContents(column)
Parameters

column – int

Resizes the column given to the size of its contents.

PySide2.QtWidgets.QTreeView.rootIsDecorated()
Return type

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 .

PySide2.QtWidgets.QTreeView.rowHeight(index)
Parameters

indexPySide2.QtCore.QModelIndex

Return type

int

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

PySide2.QtWidgets.QTreeView.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.

PySide2.QtWidgets.QTreeView.setAllColumnsShowFocus(enable)
Parameters

enable – 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.

PySide2.QtWidgets.QTreeView.setAnimated(enable)
Parameters

enable – 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 .

PySide2.QtWidgets.QTreeView.setAutoExpandDelay(delay)
Parameters

delay – 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.

PySide2.QtWidgets.QTreeView.setColumnHidden(column, hide)
Parameters
  • column – int

  • hide – bool

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

PySide2.QtWidgets.QTreeView.setColumnWidth(column, width)
Parameters
  • column – int

  • width – int

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

PySide2.QtWidgets.QTreeView.setExpanded(index, expand)
Parameters

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

PySide2.QtWidgets.QTreeView.setExpandsOnDoubleClick(enable)
Parameters

enable – 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

PySide2.QtWidgets.QTreeView.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.

PySide2.QtWidgets.QTreeView.setHeader(header)
Parameters

headerPySide2.QtWidgets.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()

PySide2.QtWidgets.QTreeView.setHeaderHidden(hide)
Parameters

hide – 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()

PySide2.QtWidgets.QTreeView.setIndentation(i)
Parameters

i – 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 stops the updates, calling will restore default behavior.

PySide2.QtWidgets.QTreeView.setItemsExpandable(enable)
Parameters

enable – 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 .

PySide2.QtWidgets.QTreeView.setRootIsDecorated(show)
Parameters

show – 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 .

PySide2.QtWidgets.QTreeView.setRowHidden(row, parent, hide)
Parameters

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

PySide2.QtWidgets.QTreeView.setSortingEnabled(enable)
Parameters

enable – 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()

PySide2.QtWidgets.QTreeView.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.

PySide2.QtWidgets.QTreeView.setUniformRowHeights(uniform)
Parameters

uniform – 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 .

PySide2.QtWidgets.QTreeView.setWordWrap(on)
Parameters

on – 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 .

PySide2.QtWidgets.QTreeView.showColumn(column)
Parameters

column – int

Shows the given column in the tree view.

PySide2.QtWidgets.QTreeView.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

PySide2.QtWidgets.QTreeView.sortByColumn(column)
Parameters

column – int

Note

This function is deprecated.

This is an overloaded function.

This function is deprecated. Use sortByColumn (int column, SortOrder order) instead. Sorts the model by the values in the given column .

PySide2.QtWidgets.QTreeView.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.

PySide2.QtWidgets.QTreeView.uniformRowHeights()
Return type

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 .

PySide2.QtWidgets.QTreeView.wordWrap()
Return type

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 .