Changing Font and background color of individual item in editable Treeview

[Stan Pamela]

Thanks @SGaist for helping out!

That doesn't seem to work. If use

    model.setData(current_index, 'QWidget { font: bold italic large "Times New Roman"; font-size: 10pt }', role=Qt.FontRole)

inside the update_actions function of mainwindow.py, together with

    if (role != Qt.EditRole) and (role != Qt.FontRole):

inside the setData function of treemodel.py, what happens is that it just replaces the text of the item by

'QWidget { font: bold italic large "Times New Roman"; font-size: 10pt }'

as if that was a normal edit action. I think this is because the editable tree version has a whole wrapper of the data itself around it...

[SGaist]

It looks like you are trying to set a style sheet in the font role.

The FontRole takes a QFont object.

You can see here more information about the roles and what they expect.

[Stan Pamela]

Ah. good point. But it still does the same. If I use

    newFont = QFont("Helvetica")
    model.setData(current_index, newFont, role=Qt.FontRole)

It just replaces the content of the item with the text "Helvetica"...

[SGaist]

@Stan-Pamela do you also have a custom data function ?

[mpergand]

@Stan-Pamela
You need to return the right data for the roles in data() not setData()

[Stan Pamela]

@SGaist yes, it's

def data(self, index: QModelIndex, role: int = None):
    if not index.isValid():
        return None

    #if role == Qt.FontRole: # sorry please ignore! that was confusing...
    #   return item.data(index.column())

    if role != Qt.DisplayRole and role != Qt.EditRole:
        return None

    item: TreeItem = self.get_item(index)

    return item.data(index.column())

which then goes to treeitem.py -> data

def data(self, column: int):
    if column < 0 or column >= len(self.item_data):
        return None
    return self.item_data[column]

in other words, it's wrapping a TreeItem to get item_data[column]. What would I need to target to return the font? or the style or background?

[SGaist]

@Stan-Pamela you are not passing the role down to your item data call.

[Stan Pamela]

@SGaist
:)
I can only reply every 600sec apparently because I'm a new user. I think you need to give me a "reputation" to be able to interact faster? :)

Anyway, really sorry about last post, that was confusing, I was trying to edit the data function and copy pasted something that wasn't working...

Still, these are the two functions that wrap around item_data

def setData(self, index: QModelIndex, value, role: int) -> bool:
    if (role != Qt.EditRole) and (role != Qt.FontRole):
        return False

    item: TreeItem = self.get_item(index)
    result: bool = item.set_data(index.column(), value)

    if result:
        self.dataChanged.emit(index, index, [Qt.DisplayRole, Qt.EditRole, Qt.FontRole])

    return result

and

def set_data(self, column: int, value):
    if column < 0 or column >= len(self.item_data):
        return False

    self.item_data[column] = value
    return True

[SGaist]

@Stan-Pamela that's another issue: you don't handle the role in your wrapper just the value.

[Stan Pamela]

@SGaist OK, how do I handle the role?
Really sorry, I know this is probably so obvious to you all, but I just can't figure it out. It seems this treeview example is a corner case with all the wrappers, isn't it? Or it's just me?

Still can't write more than every 600sec :( maybe just as well, ahah!

[SGaist]

Ok, I see the issue. The example works well for just handling "data".

You need to modify your custom TreeItem to handle the role in addition to the value. As a basic version, you can use a dictionary where the key is the role and the item the value. Add a role parameter to the set_data and data methods so that you can properly set and retrieve these values.

[Stan Pamela]

@SGaist

Thanks again. I'm still not sure how to do that...
Even for the "value" itself, could you explain how/where the final target TreeItem->item_data is set? This doesn't seem to be a standard Qt class/variable... I'm confused...

At the very end of treeitem.py, in this editable tree example, there is this recursive function:

def set_data(self, column: int, value):
    if column < 0 or column >= len(self.item_data):
        return False

    self.item_data[column] = value
    return True

def __repr__(self) -> str:
    result = f"<treeitem.TreeItem at 0x{id(self):x}"
    for d in self.item_data:
        result += f' "{d}"' if d else " <None>"
    result += f", {len(self.child_items)} children>"
    return result

Is it this repr function that's used internally, in the backend of the Qt library, to display the text manually? Do I need to use a similar backend function for the role?

[SGaist]

Basically:

     def set_data(self, column: int, value, role):
         if column < 0 or column >= len(self.item_data):
             return False
 
         if column not in self.item_data.keys():
             self.item_data[column] = {}
         self.item_data[column][role] = value
         return True

Don't forget to handle the EditRole and Display role properly.

[Stan Pamela]

That doesn't work either. Or I'm not doing it properly(?)
Even ignoring the font role, and just trying to do the simplest thing possible: to use a dict like this for the text edit alone, and replace the original functionality, it doesn't work:

def set_data(self, column: int, value):
    if column < 0 or column >= len(self.item_data):
        return False

    #self.item_data[column] = value
    self.item_data[column] = {Qt.EditRole: value}

[SGaist]

@Stan-Pamela did you adapt the data function in a similar fashion ?

[Stan Pamela]

@SGaist, got it!
Thanks so much and sorry it took me so long to understand the trail of wrappers and how that feeds back into the main model. Awesome. I did it in a dirty way for now, but shall I clean up and post a zip of the code for consistency and closure of this forum thread?

[Stan Pamela]

Thanks again so much @SGaist , @friedemannkleint and @mpergand for the help and patience. Just for the record, here are the details for a working example, based on the original https://doc.qt.io/qtforpython-6/examples/example_widgets_itemviews_editabletreemodel.html

======================
mainwindow.py:

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

import sys
from pathlib import Path

from PySide6.QtCore import (QAbstractItemModel, QItemSelectionModel,
                            QModelIndex, Qt, Slot)
from PySide6.QtWidgets import (QAbstractItemView, QMainWindow, QTreeView,
                               QWidget)
from PySide6.QtGui import QFont
from PySide6.QtTest import QAbstractItemModelTester

from treemodel import TreeModel


class MainWindow(QMainWindow):
    def __init__(self, parent: QWidget = None):
        super().__init__(parent)
        self.resize(573, 468)

        self.view = QTreeView()
        self.view.setAlternatingRowColors(True)
        self.view.setSelectionBehavior(QAbstractItemView.SelectItems)
        self.view.setHorizontalScrollMode(QAbstractItemView.ScrollPerPixel)
        self.view.setAnimated(False)
        self.view.setAllColumnsShowFocus(True)
        self.setCentralWidget(self.view)

        menubar = self.menuBar()
        file_menu = menubar.addMenu("&File")
        self.exit_action = file_menu.addAction("E&xit")
        self.exit_action.setShortcut("Ctrl+Q")
        self.exit_action.triggered.connect(self.close)

        actions_menu = menubar.addMenu("&Actions")
        actions_menu.triggered.connect(self.update_actions)
        self.insert_row_action = actions_menu.addAction("Insert Row")
        self.insert_row_action.setShortcut("Ctrl+I, R")
        self.insert_row_action.triggered.connect(self.insert_row)
        self.insert_column_action = actions_menu.addAction("Insert Column")
        self.insert_column_action.setShortcut("Ctrl+I, C")
        self.insert_column_action.triggered.connect(self.insert_column)
        actions_menu.addSeparator()
        self.remove_row_action = actions_menu.addAction("Remove Row")
        self.remove_row_action.setShortcut("Ctrl+R, R")
        self.remove_row_action.triggered.connect(self.remove_row)
        self.remove_column_action = actions_menu.addAction("Remove Column")
        self.remove_column_action.setShortcut("Ctrl+R, C")
        self.remove_column_action.triggered.connect(self.remove_column)
        actions_menu.addSeparator()
        self.insert_child_action = actions_menu.addAction("Insert Child")
        self.insert_child_action.setShortcut("Ctrl+N")
        self.insert_child_action.triggered.connect(self.insert_child)
        help_menu = menubar.addMenu("&Help")
        about_qt_action = help_menu.addAction("About Qt", qApp.aboutQt)
        about_qt_action.setShortcut("F1")

        self.setWindowTitle("Editable Tree Model")

        headers = ["Title", "Description"]

        file = Path(__file__).parent / "default.txt"
        self.model = TreeModel(headers, file.read_text(), self)

        if "-t" in sys.argv:
            QAbstractItemModelTester(self.model, self)
        self.view.setModel(self.model)
        self.view.expandAll()

        for column in range(self.model.columnCount()):
            self.view.resizeColumnToContents(column)

        selection_model = self.view.selectionModel()
        selection_model.selectionChanged.connect(self.update_actions)

        self.update_actions()

    @Slot()
    def insert_child(self) -> None:
        selection_model = self.view.selectionModel()
        index: QModelIndex = selection_model.currentIndex()
        model: QAbstractItemModel = self.view.model()

        if model.columnCount(index) == 0:
            if not model.insertColumn(0, index):
                return

        if not model.insertRow(0, index):
            return

        for column in range(model.columnCount(index)):
            child: QModelIndex = model.index(0, column, index)
            model.setData(child, "[No data]", Qt.EditRole)
            if not model.headerData(column, Qt.Horizontal):
                model.setHeaderData(column, Qt.Horizontal, "[No header]",
                                    Qt.EditRole)

        selection_model.setCurrentIndex(
            model.index(0, 0, index), QItemSelectionModel.ClearAndSelect
        )
        self.update_actions()

    @Slot()
    def insert_column(self) -> None:
        model: QAbstractItemModel = self.view.model()
        column: int = self.view.selectionModel().currentIndex().column()

        changed: bool = model.insertColumn(column + 1)
        if changed:
            model.setHeaderData(column + 1, Qt.Horizontal, "[No header]",
                                Qt.EditRole)

        self.update_actions()

    @Slot()
    def insert_row(self) -> None:
        index: QModelIndex = self.view.selectionModel().currentIndex()
        model: QAbstractItemModel = self.view.model()
        parent: QModelIndex = index.parent()

        if not model.insertRow(index.row() + 1, parent):
            return

        self.update_actions()

        for column in range(model.columnCount(parent)):
            child: QModelIndex = model.index(index.row() + 1, column, parent)
            model.setData(child, "[No data]", Qt.EditRole)

    @Slot()
    def remove_column(self) -> None:
        model: QAbstractItemModel = self.view.model()
        column: int = self.view.selectionModel().currentIndex().column()

        if model.removeColumn(column):
            self.update_actions()

    @Slot()
    def remove_row(self) -> None:
        index: QModelIndex = self.view.selectionModel().currentIndex()
        model: QAbstractItemModel = self.view.model()

        if model.removeRow(index.row(), index.parent()):
            self.update_actions()

    @Slot()
    def update_actions(self) -> None:
        selection_model = self.view.selectionModel()
        has_selection: bool = not selection_model.selection().isEmpty()
        self.remove_row_action.setEnabled(has_selection)
        self.remove_column_action.setEnabled(has_selection)

        current_index = selection_model.currentIndex()
        has_current: bool = current_index.isValid()
        self.insert_row_action.setEnabled(has_current)
        self.insert_column_action.setEnabled(has_current)

        model: QAbstractItemModel = self.view.model()
        newFont = QFont("Times New Roman", 20, QFont.Bold)
        newFont.setItalic(True)
        model.setData(current_index, newFont, role=Qt.FontRole)

        if has_current:
            self.view.closePersistentEditor(current_index)
            msg = f"Position: ({current_index.row()},{current_index.column()})"
            if not current_index.parent().isValid():
                msg += " in top level"
            self.statusBar().showMessage(msg)

======================
treeitem.py:

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause


class TreeItem:
    def __init__(self, data: list, parent: 'TreeItem' = None):
        self.item_data = data
        self.item_font = [None] * len(data)
        self.parent_item = parent
        self.child_items = []

    def child(self, number: int) -> 'TreeItem':
        if number < 0 or number >= len(self.child_items):
            return None
        return self.child_items[number]

    def last_child(self):
        return self.child_items[-1] if self.child_items else None

    def child_count(self) -> int:
        return len(self.child_items)

    def child_number(self) -> int:
        if self.parent_item:
            return self.parent_item.child_items.index(self)
        return 0

    def column_count(self) -> int:
        return len(self.item_data)

    def font(self, column: int):
        if column < 0 or column >= len(self.item_data):
            return None
        return self.item_font[column]

    def data(self, column: int):
        if column < 0 or column >= len(self.item_data):
            return None
        return self.item_data[column]

    def insert_children(self, position: int, count: int, columns: int) -> bool:
        if position < 0 or position > len(self.child_items):
            return False

        for row in range(count):
            data = [None] * columns
            item = TreeItem(data.copy(), self)
            self.child_items.insert(position, item)

        return True

    def insert_columns(self, position: int, columns: int) -> bool:
        if position < 0 or position > len(self.item_data):
            return False

        for column in range(columns):
            self.item_data.insert(position, None)

        for child in self.child_items:
            child.insert_columns(position, columns)

        return True

    def parent(self):
        return self.parent_item

    def remove_children(self, position: int, count: int) -> bool:
        if position < 0 or position + count > len(self.child_items):
            return False

        for row in range(count):
            self.child_items.pop(position)

        return True

    def remove_columns(self, position: int, columns: int) -> bool:
        if position < 0 or position + columns > len(self.item_data):
            return False

        for column in range(columns):
            self.item_data.pop(position)

        for child in self.child_items:
            child.remove_columns(position, columns)

        return True

    def set_font(self, column: int, value):
        if column < 0 or column >= len(self.item_data):
            return False

        self.item_font[column] = value
        return True

    def set_data(self, column: int, value):
        if column < 0 or column >= len(self.item_data):
            return False

        self.item_data[column] = value
        return True

    def __repr__(self) -> str:
        result = f"<treeitem.TreeItem at 0x{id(self):x}"
        for d in self.item_data:
            result += f' "{d}"' if d else " <None>"
        result += f", {len(self.child_items)} children>"
        return result

======================
treemodel.py:

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause


from PySide6.QtCore import QModelIndex, Qt, QAbstractItemModel
from treeitem import TreeItem


class TreeModel(QAbstractItemModel):

    def __init__(self, headers: list, data: str, parent=None):
        super().__init__(parent)

        self.root_data = headers
        self.root_item = TreeItem(self.root_data.copy())
        self.setup_model_data(data.split("\n"), self.root_item)

    def columnCount(self, parent: QModelIndex = None) -> int:
        return self.root_item.column_count()

    def data(self, index: QModelIndex, role: int = None):
        if not index.isValid():
            return None

        if role != Qt.DisplayRole and role != Qt.EditRole and role != Qt.FontRole:
            return None

        item: TreeItem = self.get_item(index)

        if role == Qt.FontRole:
            return item.font(index.column())

        return item.data(index.column())

    def flags(self, index: QModelIndex) -> Qt.ItemFlags:
        if not index.isValid():
            return Qt.NoItemFlags

        return Qt.ItemIsEditable | QAbstractItemModel.flags(self, index)

    def get_item(self, index: QModelIndex = QModelIndex()) -> TreeItem:
        if index.isValid():
            item: TreeItem = index.internalPointer()
            if item:
                return item

        return self.root_item

    def headerData(self, section: int, orientation: Qt.Orientation,
                   role: int = Qt.DisplayRole):
        if orientation == Qt.Horizontal and role == Qt.DisplayRole:
            return self.root_item.data(section)

        return None

    def index(self, row: int, column: int, parent: QModelIndex = QModelIndex()) -> QModelIndex:
        if parent.isValid() and parent.column() != 0:
            return QModelIndex()

        parent_item: TreeItem = self.get_item(parent)
        if not parent_item:
            return QModelIndex()

        child_item: TreeItem = parent_item.child(row)
        if child_item:
            return self.createIndex(row, column, child_item)
        return QModelIndex()

    def insertColumns(self, position: int, columns: int,
                      parent: QModelIndex = QModelIndex()) -> bool:
        self.beginInsertColumns(parent, position, position + columns - 1)
        success: bool = self.root_item.insert_columns(position, columns)
        self.endInsertColumns()

        return success

    def insertRows(self, position: int, rows: int,
                   parent: QModelIndex = QModelIndex()) -> bool:
        parent_item: TreeItem = self.get_item(parent)
        if not parent_item:
            return False

        self.beginInsertRows(parent, position, position + rows - 1)
        column_count = self.root_item.column_count()
        success: bool = parent_item.insert_children(position, rows, column_count)
        self.endInsertRows()

        return success

    def parent(self, index: QModelIndex = QModelIndex()) -> QModelIndex:
        if not index.isValid():
            return QModelIndex()

        child_item: TreeItem = self.get_item(index)
        if child_item:
            parent_item: TreeItem = child_item.parent()
        else:
            parent_item = None

        if parent_item == self.root_item or not parent_item:
            return QModelIndex()

        return self.createIndex(parent_item.child_number(), 0, parent_item)

    def removeColumns(self, position: int, columns: int,
                      parent: QModelIndex = QModelIndex()) -> bool:
        self.beginRemoveColumns(parent, position, position + columns - 1)
        success: bool = self.root_item.remove_columns(position, columns)
        self.endRemoveColumns()

        if self.root_item.column_count() == 0:
            self.removeRows(0, self.rowCount())

        return success

    def removeRows(self, position: int, rows: int,
                   parent: QModelIndex = QModelIndex()) -> bool:
        parent_item: TreeItem = self.get_item(parent)
        if not parent_item:
            return False

        self.beginRemoveRows(parent, position, position + rows - 1)
        success: bool = parent_item.remove_children(position, rows)
        self.endRemoveRows()

        return success

    def rowCount(self, parent: QModelIndex = QModelIndex()) -> int:
        if parent.isValid() and parent.column() > 0:
            return 0

        parent_item: TreeItem = self.get_item(parent)
        if not parent_item:
            return 0
        return parent_item.child_count()

    def setData(self, index: QModelIndex, value, role: int) -> bool:
        if (role != Qt.EditRole) and (role != Qt.FontRole):
            return False

        item: TreeItem = self.get_item(index)
        if role == Qt.FontRole:
            result: bool = item.set_font(index.column(), value)
        else:
            result: bool = item.set_data(index.column(), value)

        if result:
            self.dataChanged.emit(index, index, [Qt.DisplayRole, Qt.EditRole, Qt.FontRole])

        return result

    def setHeaderData(self, section: int, orientation: Qt.Orientation, value,
                      role: int = None) -> bool:
        if role != Qt.EditRole or orientation != Qt.Horizontal:
            return False

        result: bool = self.root_item.set_data(section, value)

        if result:
            self.headerDataChanged.emit(orientation, section, section)

        return result

    def setup_model_data(self, lines: list, parent: TreeItem):
        parents = [parent]
        indentations = [0]

        for line in lines:
            line = line.rstrip()
            if line and "\t" in line:

                position = 0
                while position < len(line):
                    if line[position] != " ":
                        break
                    position += 1

                column_data = line[position:].split("\t")
                column_data = [string for string in column_data if string]

                if position > indentations[-1]:
                    if parents[-1].child_count() > 0:
                        parents.append(parents[-1].last_child())
                        indentations.append(position)
                else:
                    while position < indentations[-1] and parents:
                        parents.pop()
                        indentations.pop()

                parent: TreeItem = parents[-1]
                col_count = self.root_item.column_count()
                parent.insert_children(parent.child_count(), 1, col_count)

                for column in range(len(column_data)):
                    child = parent.last_child()
                    child.set_data(column, column_data[column])

    def _repr_recursion(self, item: TreeItem, indent: int = 0) -> str:
        result = " " * indent + repr(item) + "\n"
        for child in item.child_items:
            result += self._repr_recursion(child, indent + 2)
        return result

    def __repr__(self) -> str:
        return self._repr_recursion(self.root_item)