PyQt - Column of Checkboxes in a QTableView


PyQt - Column of Checkboxes in a QTableView



I am dynamically creating a QTableView from a Pandas dataframe. I have example code here.



I can create the table, with the checkboxes but I cannot get the checkboxes to reflect the model data, or even to change at all to being unchecked.



I am following example code from this previous question and taking @raorao answer as a guide. This will display the boxes in the table, but non of the functionality is working.



Can anyone suggest any changes, or what is wrong with this code. Why is it not reflecting the model, and why can it not change?



Do check out my full example code here.



Edit one : Update after comment from Frodon :
corrected string cast to bool with a comparison xxx == 'True'


class CheckBoxDelegate(QtGui.QStyledItemDelegate):
"""
A delegate that places a fully functioning QCheckBox in every
cell of the column to which it's applied
"""
def __init__(self, parent):
QtGui.QItemDelegate.__init__(self, parent)

def createEditor(self, parent, option, index):
'''
Important, otherwise an editor is created if the user clicks in this cell.
** Need to hook up a signal to the model
'''
return None

def paint(self, painter, option, index):
'''
Paint a checkbox without the label.
'''
checked = index.model().data(index, QtCore.Qt.DisplayRole) == 'True'
check_box_style_option = QtGui.QStyleOptionButton()

if (index.flags() & QtCore.Qt.ItemIsEditable) > 0:
check_box_style_option.state |= QtGui.QStyle.State_Enabled
else:
check_box_style_option.state |= QtGui.QStyle.State_ReadOnly

if checked:
check_box_style_option.state |= QtGui.QStyle.State_On
else:
check_box_style_option.state |= QtGui.QStyle.State_Off

check_box_style_option.rect = self.getCheckBoxRect(option)

# this will not run - hasFlag does not exist
#if not index.model().hasFlag(index, QtCore.Qt.ItemIsEditable):
#check_box_style_option.state |= QtGui.QStyle.State_ReadOnly

check_box_style_option.state |= QtGui.QStyle.State_Enabled

QtGui.QApplication.style().drawControl(QtGui.QStyle.CE_CheckBox, check_box_style_option, painter)

def editorEvent(self, event, model, option, index):
'''
Change the data in the model and the state of the checkbox
if the user presses the left mousebutton or presses
Key_Space or Key_Select and this cell is editable. Otherwise do nothing.
'''
print 'Check Box editor Event detected : '
if not (index.flags() & QtCore.Qt.ItemIsEditable) > 0:
return False

print 'Check Box edior Event detected : passed first check'
# Do not change the checkbox-state
if event.type() == QtCore.QEvent.MouseButtonRelease or event.type() == QtCore.QEvent.MouseButtonDblClick:
if event.button() != QtCore.Qt.LeftButton or not self.getCheckBoxRect(option).contains(event.pos()):
return False
if event.type() == QtCore.QEvent.MouseButtonDblClick:
return True
elif event.type() == QtCore.QEvent.KeyPress:
if event.key() != QtCore.Qt.Key_Space and event.key() != QtCore.Qt.Key_Select:
return False
else:
return False

# Change the checkbox-state
self.setModelData(None, model, index)
return True





Is this line: checked = bool(index.model().data(index, QtCore.Qt.DisplayRole)) really gives a boolean ? I would have written checked = index.model().data(index, QtCore.Qt.DisplayRole).toBool() because the result of data() is a QVariant.
– Frodon
Jul 22 '13 at 9:41


checked = bool(index.model().data(index, QtCore.Qt.DisplayRole))


checked = index.model().data(index, QtCore.Qt.DisplayRole).toBool()





Interestingly enough I did try that first, but received an error: AttributeError: 'str' object has no attribute 'toBool' so settled on the cast instead. Thanks.
– drexiya
Jul 22 '13 at 10:35






On further investigation, the cast is incorrect, as it will always return True, if the value is non-zero. I have modified to checked = index.model().data(index, QtCore.Qt.DisplayRole) == 'True'. This now reflects the data correctly, but has not solved the problem completely as it still will not change. Thanks again for your comment. I will update the question.
– drexiya
Jul 22 '13 at 10:52




3 Answers
3



I've found a solution for you. The trick was:


setData


data



Here it is. (I had to create a class called Dataframe, to make the example work without pandas. Please replace all the if has_pandas statements by yours):


Dataframe


if has_pandas


from PyQt4 import QtCore, QtGui

has_pandas = False
try:
import pandas as pd
has_pandas = True
except:
pass

class TableModel(QtCore.QAbstractTableModel):
def __init__(self, parent=None, *args):
super(TableModel, self).__init__()
self.datatable = None
self.headerdata = None

def update(self, dataIn):
print 'Updating Model'
self.datatable = dataIn
print 'Datatable : {0}'.format(self.datatable)
if has_pandas:
headers = dataIn.columns.values
else:
headers = dataIn.columns
header_items = [
str(field)
for field in headers
]
self.headerdata = header_items
print 'Headers'
print self.headerdata

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

def columnCount(self, parent=QtCore.QModelIndex()):
if has_pandas:
return len(self.datatable.columns.values)
else:
return len(self.datatable.columns)

def data(self, index, role=QtCore.Qt.DisplayRole):
if role == QtCore.Qt.DisplayRole:
i = index.row()
j = index.column()
return QtCore.QVariant('{0}'.format(self.datatable.iget_value(i, j)))
else:
return QtCore.QVariant()

def setData(self, index, value, role=QtCore.Qt.DisplayRole):
if index.column() == 4:
self.datatable.iset_value(index.row(), 4, value)
return value
return value

def headerData(self, col, orientation, role):
if orientation == QtCore.Qt.Horizontal and role == QtCore.Qt.DisplayRole:
return '{0}'.format(self.headerdata[col])

def flags(self, index):
if index.column() == 4:
return QtCore.Qt.ItemIsEditable | QtCore.Qt.ItemIsEnabled
else:
return QtCore.Qt.ItemIsEnabled


class TableView(QtGui.QTableView):
"""
A simple table to demonstrate the QComboBox delegate.
"""
def __init__(self, *args, **kwargs):
QtGui.QTableView.__init__(self, *args, **kwargs)
self.setItemDelegateForColumn(4, CheckBoxDelegate(self))


class CheckBoxDelegate(QtGui.QStyledItemDelegate):
"""
A delegate that places a fully functioning QCheckBox in every
cell of the column to which it's applied
"""
def __init__(self, parent):
QtGui.QItemDelegate.__init__(self, parent)

def createEditor(self, parent, option, index):
'''
Important, otherwise an editor is created if the user clicks in this cell.
** Need to hook up a signal to the model
'''
return None

def paint(self, painter, option, index):
'''
Paint a checkbox without the label.
'''

checked = index.data().toBool()
check_box_style_option = QtGui.QStyleOptionButton()

if (index.flags() & QtCore.Qt.ItemIsEditable) > 0:
check_box_style_option.state |= QtGui.QStyle.State_Enabled
else:
check_box_style_option.state |= QtGui.QStyle.State_ReadOnly

if checked:
check_box_style_option.state |= QtGui.QStyle.State_On
else:
check_box_style_option.state |= QtGui.QStyle.State_Off

check_box_style_option.rect = self.getCheckBoxRect(option)

# this will not run - hasFlag does not exist
#if not index.model().hasFlag(index, QtCore.Qt.ItemIsEditable):
#check_box_style_option.state |= QtGui.QStyle.State_ReadOnly

check_box_style_option.state |= QtGui.QStyle.State_Enabled

QtGui.QApplication.style().drawControl(QtGui.QStyle.CE_CheckBox, check_box_style_option, painter)

def editorEvent(self, event, model, option, index):
'''
Change the data in the model and the state of the checkbox
if the user presses the left mousebutton or presses
Key_Space or Key_Select and this cell is editable. Otherwise do nothing.
'''
print 'Check Box editor Event detected : '
print event.type()
if not (index.flags() & QtCore.Qt.ItemIsEditable) > 0:
return False

print 'Check Box editor Event detected : passed first check'
# Do not change the checkbox-state
if event.type() == QtCore.QEvent.MouseButtonPress:
return False
if event.type() == QtCore.QEvent.MouseButtonRelease or event.type() == QtCore.QEvent.MouseButtonDblClick:
if event.button() != QtCore.Qt.LeftButton or not self.getCheckBoxRect(option).contains(event.pos()):
return False
if event.type() == QtCore.QEvent.MouseButtonDblClick:
return True
elif event.type() == QtCore.QEvent.KeyPress:
if event.key() != QtCore.Qt.Key_Space and event.key() != QtCore.Qt.Key_Select:
return False
else:
return False

# Change the checkbox-state
self.setModelData(None, model, index)
return True

def setModelData (self, editor, model, index):
'''
The user wanted to change the old state in the opposite.
'''
print 'SetModelData'
newValue = not index.data().toBool()
print 'New Value : {0}'.format(newValue)
model.setData(index, newValue, QtCore.Qt.EditRole)

def getCheckBoxRect(self, option):
check_box_style_option = QtGui.QStyleOptionButton()
check_box_rect = QtGui.QApplication.style().subElementRect(QtGui.QStyle.SE_CheckBoxIndicator, check_box_style_option, None)
check_box_point = QtCore.QPoint (option.rect.x() +
option.rect.width() / 2 -
check_box_rect.width() / 2,
option.rect.y() +
option.rect.height() / 2 -
check_box_rect.height() / 2)
return QtCore.QRect(check_box_point, check_box_rect.size())


###############################################################################################################################
class Dataframe(dict):
def __init__(self, columns, values):
if len(values) != len(columns):
raise Exception("Bad values")
self.columns = columns
self.values = values
self.index = values[0]
super(Dataframe, self).__init__(dict(zip(columns, values)))
pass

def iget_value(self, i, j):
return(self.values[j][i])

def iset_value(self, i, j, value):
self.values[j][i] = value


if __name__=="__main__":
from sys import argv, exit

class Widget(QtGui.QWidget):
"""
A simple test widget to contain and own the model and table.
"""
def __init__(self, parent=None):
QtGui.QWidget.__init__(self, parent)

l=QtGui.QVBoxLayout(self)
cdf = self.get_data_frame()
self._tm=TableModel(self)
self._tm.update(cdf)
self._tv=TableView(self)
self._tv.setModel(self._tm)
for row in range(0, self._tm.rowCount()):
self._tv.openPersistentEditor(self._tm.index(row, 4))
self.setGeometry(300, 300, 550, 200)
l.addWidget(self._tv)

def get_data_frame(self):
if has_pandas:
df = pd.DataFrame({'Name':['a','b','c','d'],
'First':[2.3,5.4,3.1,7.7], 'Last':[23.4,11.2,65.3,88.8], 'Class':[1,1,2,1], 'Valid':[True, False, True, False]})
else:
columns = ['Name', 'First', 'Last', 'Class', 'Valid']
values = [['a','b','c','d'], [2.3,5.4,3.1,7.7], [23.4,11.2,65.3,88.8], [1,1,2,1], [True, False, True, False]]
df = Dataframe(columns, values)
return df

a=QtGui.QApplication(argv)
w=Widget()
w.show()
w.raise_()
exit(a.exec_())





Yes I had come to a similar solution after fixing the data reflection. The set data method is the obvious culprit. Your approach looks fine so am happy to accept your answer. A couple of improvements can be made. For example I did not like the solution of making the setData() and flags() functions column specific, but it should not be to hard to code around this.
– drexiya
Jul 23 '13 at 8:36





AttributeError: 'NoneType' object has no attribute 'toBool'. Lots of other warnings came up, this should probably be retooled, especially to fit PySide which doesn't use QVariants...
– neuronet
Jul 16 '15 at 21:25



AttributeError: 'NoneType' object has no attribute 'toBool'





Trying to adapt to qstandarditemmodel, and only one checkbox is showing, have posted follow-up question: stackoverflow.com/questions/31478121/…
– neuronet
Jul 17 '15 at 17:20





Is the else block in the QtCore.QEvent.KeyPress block there on purpose and what is it supposed to do?
– Tim
Jun 29 at 9:05



QtCore.QEvent.KeyPress





I think it's a typo. The else block should return True (as far as I can remember the script)
– Frodon
Jun 29 at 9:31



I added


if event.type() == QEvent.MouseButtonPress or event.type() == QEvent.MouseMove:
return False



to prevent checkbox from flickering when moving the mouse





*** ok nice tip +1 ***
– drexiya
Sep 24 '13 at 17:00



Here's a port of the same code above for PyQt5.
Posting here as there doesn't appear to be another example of a working CheckBox Delegate in QT5, and i was tearing my hair out trying to get it working. Hopefully it's useful to someone.


from PyQt5 import QtCore, QtWidgets
from PyQt5.QtCore import QModelIndex
from PyQt5.QtGui import QStandardItemModel
from PyQt5.QtWidgets import QApplication, QTableView

class CheckBoxDelegate(QtWidgets.QItemDelegate):
"""
A delegate that places a fully functioning QCheckBox cell of the column to which it's applied.
"""
def __init__(self, parent):
QtWidgets.QItemDelegate.__init__(self, parent)

def createEditor(self, parent, option, index):
"""
Important, otherwise an editor is created if the user clicks in this cell.
"""
return None

def paint(self, painter, option, index):
"""
Paint a checkbox without the label.
"""
self.drawCheck(painter, option, option.rect, QtCore.Qt.Unchecked if int(index.data()) == 0 else QtCore.Qt.Checked)

def editorEvent(self, event, model, option, index):
'''
Change the data in the model and the state of the checkbox
if the user presses the left mousebutton and this cell is editable. Otherwise do nothing.
'''
if not int(index.flags() & QtCore.Qt.ItemIsEditable) > 0:
return False

if event.type() == QtCore.QEvent.MouseButtonRelease and event.button() == QtCore.Qt.LeftButton:
# Change the checkbox-state
self.setModelData(None, model, index)
return True

return False


def setModelData (self, editor, model, index):
'''
The user wanted to change the old state in the opposite.
'''
model.setData(index, 1 if int(index.data()) == 0 else 0, QtCore.Qt.EditRole)



if __name__ == '__main__':

import sys

app = QApplication(sys.argv)

model = QStandardItemModel(4, 3)
tableView = QTableView()
tableView.setModel(model)

delegate = CheckBoxDelegate(None)
tableView.setItemDelegateForColumn(1, delegate)
for row in range(4):
for column in range(3):
index = model.index(row, column, QModelIndex())
model.setData(index, 1)

tableView.setWindowTitle("Check Box Delegate")
tableView.show()
sys.exit(app.exec_())






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