headerData of qabstracttablemodel unable to return QtCore.QVariant(list of strings)

blossomsg

Hello guys,
i am creating a qabstracttablemodel and setting that into my view, but the view is unable to load the list

this works fine
QtCore.QVariant(str("Col 2"))

but when i pass
QtCore.QVariant(self.stringsList)

it does not show me in the ui, i have no clue why, i even checked the typeName and it is QVariantList, still no
i tried forloop the list with str(x) still no,
i went through alot of the c++ docs and most of them said stringlist works with qvariantlist so i did not understand why it isn't working,
need some wisdom here

My ui file converted to py file

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'D:\All_Projs\Qt_Designer_Proj\table_view_with_delegates_for_different_column\tableview_delegate\ui\table_view_delgate.ui'
#
# Created by: PyQt5 UI code generator 5.15.4
#
# WARNING: Any manual changes made to this file will be lost when pyuic5 is
# run again.  Do not edit this file unless you know what you are doing.


from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(552, 489)
        self.verticalLayout = QtWidgets.QVBoxLayout(Form)
        self.verticalLayout.setObjectName("verticalLayout")
        self.label = QtWidgets.QLabel(Form)
        self.label.setObjectName("label")
        self.verticalLayout.addWidget(self.label)
        self.tableView = QtWidgets.QTableView(Form)
        self.tableView.setObjectName("tableView")
        self.verticalLayout.addWidget(self.tableView)

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.label.setText(_translate("Form", "table_view"))

BaseClass - you need to run this to get the ui

from ui.table_view_delgate import Ui_Form
from tablemodel import TableModel
from PyQt5 import QtWidgets
import sys

strings = ["test_01", "test_02", "test_03", "test_04"]


class TableView(QtWidgets.QWidget):
	"""
	Tableview to test the delegates for multiple rows and columns
	"""

	def __init__(self):
		super(TableView, self).__init__()
		self.ui = Ui_Form()
		self.ui.setupUi(self)
		self.model = TableModel(strings)
		self.ui.tableView.setModel(self.model)
		self.horizontalHeader = self.ui.tableView.horizontalHeader()
		self.horizontalHeader.setVisible(True)


app = QtWidgets.QApplication(sys.argv)
window = TableView()
window.show()
sys.exit(app.exec_())

model class - my QAbstractTableModel class for showing row and column

from PyQt5 import QtCore

class TableModel(QtCore.QAbstractTableModel):
	def __init__(self, strings, parent=None):
		super(TableModel, self).__init__(parent)

		self.stringsList = strings

	def rowCount(self, index=QtCore.QModelIndex()):
		return len(self.stringsList)

	def columnCount(self, index=QtCore.QModelIndex()):
		return len(self.stringsList)

	def data(self, index=QtCore.QModelIndex(), role=QtCore.Qt.DisplayRole):
		if not index.isValid():
			return None
		elif role != QtCore.Qt.DisplayRole:
			return None

	def headerData(self, section, orientation=QtCore.Qt.Orientation, role=QtCore.Qt.DisplayRole):
		if role == QtCore.Qt.DisplayRole:
			if orientation == QtCore.Qt.Horizontal:
				if section == 0:
					return QtCore.QVariant(str("Col 2"))
			if orientation == QtCore.Qt.Vertical:
				if section == 0:
					return QtCore.QVariant(str("Row 1"))

JonB

@blossomsg
Your TableModel.data() method does not access self.stringsList in any way, and never returns anything, so I don't know what you expect?

You will want at minimum something like:

	def data(self, index=QtCore.QModelIndex(), role=QtCore.Qt.DisplayRole):
		if not index.isValid():
			return None
		if role == QtCore.Qt.DisplayRole:
			return self.stringsList[index.row()]

You also have both rowCount() & columnCount() returning len(self.stringsList), which can't be right. The strings are (presumably) your rows, so columnCount() should just return 1, or maybe vice versa if you want them to show as columns rather than rows. Either way, your string list is one-dimensional, so it can only be the data for either rows or columns.

blossomsg

Apologies if i did not explain well,
in my TableModel.headerData i want to pass a list
currently if you see i am passing str("Col 2") for section 0
for section 1 i'll have to pass str("Col 3") and so on

is there any way to pass list?

and how did you highlight all the specifics in pink in your comment?

SGaist

Hi,

You may store the data as a list but there's no reason for a list to be returned unless you have your own QHeaderView that handles that use case.

JonB

@blossomsg
As @SGaist has said. You can make headerData() work from a an internal list of header strings in the same way as your data() intends to use self.stringsList for its data. Like:

self.headerStrings = ["Col0", "Col1", ...]
...
def headerData(self, section, orientation=QtCore.Qt.Orientation, role=QtCore.Qt.DisplayRole):
	if role == QtCore.Qt.DisplayRole:
		if orientation == QtCore.Qt.Horizontal:
			return self.headerStrings[section]

The "pinks", as you call them, are for code/literals --- note they are in monospace font. For an inline code you enclose it in single backticks; type:

This is `code inside backticks` within a line

shows as

This is code inside backticks within a line

For multiline blocks, like a whole block of code, put triple-backticks immediately before & after; type:

    ```
    This is code
    across multiple lines
    ```

shows as

This is code
across multiple lines

blossomsg

@JonB and @SGaist ,
Thank you guys everything works superb the output that i was looking for is above

2 new things that i learnt,
we could parent the argument
self.headerStrings[section] like you did ---- how did you know we could use arguments in such manner @JonB ?

plus i did something really foolish
if section == 0: return QtCore.QVariant(str("Col 2")) in the TableModel.headerData
0 limits the value for section output to position 0 only and QtCore.QVariant did not work for lists the above is the best answer

but i'll will definitely try @SGaist what you suggested Qheaderview, if there is any page that you could suggest or any book?

Thank you.

SGaist

@blossomsg said in headerData of qabstracttablemodel unable to return QtCore.QVariant(list of strings):

we could parent the argument
self.headerStrings[section] like you did ---- how did you know we could use arguments in such manner @JonB ?

There's no parenting done. Are you talking about the usage of self ?

As for the arguments question: section will go from 0 to number of sections minus one. The headerStrings list has the same size and its content is properly ordered hence the fine result you have.

eyllanesc

@blossomsg In python it is not necessary to use QVariant since, unlike c++, the typing is dynamic and the conversion to QVariant is done by the binding

blossomsg

@SGaist

headerStrings[section] only this, what is this logic, apologies i don't understand this specific

for example
if one is using listWigdet.items(list_of_strings)

but in the headerData(section, orientation=QtCore.Qt.Orientation, role=QtCore.Qt.DisplayRole)
how is this the otherway headerStrings[section]
the list is outside and section is in boxbrackets

just trying to understand what is the concept here

same thing after i applied [section] i searched on google
https://wiki.qt.io/Qt_for_Python_Tutorial:_Data_Visualization_Tool
https://stackoverflow.com/questions/41510927/pyqt-horizontal-and-vertical-headers

are we replacing??

JonB

@blossomsg
I was the person who wrote the headerData() definition earlier. I don't understand what you are asking here.

self.headerStrings = ["Col0", "Col1", ...]

In TableModel I am declaring a member variable, self.headerStrings. It is a Python array/list because I set it to ["Col0", "Col1", ...]. That is an array/list of strings. Clearly "Col0" is intended to be the header for column #0, "Col1" the header for column #1, and so on.

def headerData(self, section, orientation=QtCore.Qt.Orientation, role=QtCore.Qt.DisplayRole):
    ...
    return self.headerStrings[section]

Qt passes section to this method and wants the header string for the column at section to be returned. So I can just use section as the index into self.headerStrings[] to retrieve the header for that column/section.

That's all there is to it.

blossomsg

@JonB
Hey sorry for the trouble, the last line explains a lot of logic, i had never seen such an approach in python and nor in pyqt, so i got confused
we usually use class.method(some datatypes) to execute/return values directly to the view/ui.
This was new, Thank you for taking out time.
Can you suggest any pages where i can refer such examples?
But for now i'll close ticket.