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Python 3.5.1: QVariant represents a mapped type and cannot be instantiated

I'm working with Python 3.5.1 and I'm trying to run this code but I have a problem with QVariant
from PyQt4.QtCore import *
from PyQt4.QtGui import *
import sys
class Model(QAbstractTableModel):
def __init__(self, parent=None, *args):
QAbstractTableModel.__init__(self, parent, *args)
self.items = ['Item_A_001','Item_A_002','Item_B_001','Item_B_002']
def rowCount(self, parent=QModelIndex()):
return len(self.items)
def columnCount(self, parent=QModelIndex()):
return 1
def data(self, index, role):
if not index.isValid(): return QVariant()
elif role != Qt.DisplayRole:
return QVariant()
row=index.row()
if row<len(self.items):
return QVariant(self.items[row])
else:
return QVariant()
class Proxy(QSortFilterProxyModel):
def __init__(self):
super(Proxy, self).__init__()
self.filterActive = False
def setView(self, view):
self._view = view
def filterAcceptsRow(self, row, parent):
if self.filterActive and '_B_' in self.sourceModel().data(self.sourceModel().index(row, 0), Qt.DisplayRole).toPyObject():
self._view.selectRow(row)
return True
class MyWindow(QWidget):
def __init__(self, *args):
QWidget.__init__(self, *args)
tableModel=Model(self)
proxyModel=Proxy()
proxyModel.setSourceModel(tableModel)
self.tableview=QTableView(self)
self.tableview.setModel(proxyModel)
self.tableview.horizontalHeader().setStretchLastSection(True)
self.tableview.setSelectionMode(QAbstractItemView.MultiSelection)
proxyModel.setView(self.tableview)
button=QPushButton(self)
button.setText('Select Items with B')
button.clicked.connect(self.clicked)
layout = QVBoxLayout(self)
layout.addWidget(self.tableview)
layout.addWidget(button)
self.setLayout(layout)
def clicked(self, arg):
proxyModel=self.tableview.model()
self.tableview.clearSelection()
proxyModel.filterActive = True
proxyModel.invalidateFilter()
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())
Indeed, when I execute this code an error message appears: QVariant Represents a mapped kind and can not be instantiated .
I tried to remove the QVariant and putting None inplace
def data(self, index, role):
if not index.isValid(): return None
elif role != Qt.DisplayRole:
return None
row=index.row()
if row<len(self.items):
return (self.items[row])
else:
return None
But a new error message appears: 'str' object has no attribute 'toPyObject'.
Thank you for helping me

As you've found out, by default, QVariant does not exist in PyQt4 when used with Python3. Instead, everything is automatically converted to an equivalent python type. So all you need to do is use None wherever QVariant.null would normally be expected, and avoid attempting to use any QVariant methods (such as toPyObject, which is obviously redundant anyway).

How to sort and filter using QAbstractTableModel instead of QSortFilterProxyModel

I attempt to filter self.items's objects by their self.category attribute all from inside of QAbstractTableModel's data() method by comparing this attribute agains a text currently displayed in the QComboBox. Yet, the code doesn't function properly.
Shouldn't be QAbstractTableModel's data() method used "as a substitute to proxy model's accepts row() method?
Is it be possible to achieve the filtering without using QSortFilterProxyModel? If we have to use proxy to filter the model items what would be most Pythonic way of doing this?
from PySide import QtGui, QtCore
class Item(object):
def __init__(self):
self.ID=None
self.name=None
self.category=None
class TableModel(QtCore.QAbstractTableModel):
def __init__(self, parent=None):
QtCore.QAbstractTableModel.__init__(self, parent)
self.items = []
self.filterCategory = None
def rowCount(self, parent=QtCore.QModelIndex()):
return len( [item for item in self.items if item.category==self.filterCategory] )
def columnCount(self, parent=QtCore.QModelIndex()):
return 1
def data(self, index, role):
if not index.isValid(): return
row=index.row()
item=self.items[row]
if item.category!=self.filterCategory:
return
if role == QtCore.Qt.DisplayRole:
return self.items[row].name
if role == QtCore.Qt.UserRole:
return self.items[row]
def insertRows(self, row, item, column=1, index=QtCore.QModelIndex()):
self.beginInsertRows(QtCore.QModelIndex(), row, row+1)
self.items.append(item)
self.endInsertRows()
def setFilter(self, comboText):
self.filterCategory = comboText
self.layoutChanged.emit()
def filterAcceptsRow(self, row, proc):
index=self.sourceModel().index(row, 0, proc)
item=self.sourceModel().data(index, QtCore.Qt.UserRole)
if not item: return True
resourceType=item.category
if self.filters.get(category)==False:
return False
if self.searchText and len(self.searchText)>0 and item.searchString(self.searchText)==False:
return False
return True
class MyWindow(QtGui.QWidget):
def __init__(self, *args):
QtGui.QWidget.__init__(self, *args)
vLayout=QtGui.QVBoxLayout(self)
self.setLayout(vLayout)
self.tableModel = TableModel()
self.ViewA=QtGui.QTableView(self)
self.ViewA.clicked.connect(self.viewClicked)
vLayout.addWidget(self.ViewA)
for row in range(5):
item=Item()
item.ID=row
if item.ID%2: item.category='Pet'
else: item.category='Birds'
item.name='%s_%s'%(item.category, row)
self.tableModel.insertRows(row, item)
self.ViewA.setModel(self.tableModel)
self.combo=QtGui.QComboBox()
self.combo.addItems(['Pet','Birds'])
self.combo.activated.connect(self.comboActivated)
vLayout.addWidget(self.combo)
currentComboCategory=self.combo.currentText()
self.tableModel.setFilter(currentComboCategory)
def viewClicked(self, indexClicked):
print('indexClicked() row: %s column: %s'%(indexClicked.row(), indexClicked.column() ))
def comboActivated(self, arg=None):
comboText=self.combo.currentText()
self.tableModel.setFilter(comboText)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())

"no-more-proxy" code below shows how to sort and filter from inside of QAbstractTableModel instead of proxy:
import sys, os
from PyQt import QtGui, QtCore
class Item(object):
def __init__(self,ID=None,name=None,category=None,area=None):
self.ID=ID
self.name=name
self.category=category
self.area='South'
class TableModel(QtCore.QAbstractTableModel):
def __init__(self, parent=None):
QtCore.QAbstractTableModel.__init__(self, parent)
self.currentItems=[]
self.items = []
self.filterCategory = None
self.searchField = None
self.mainColumn=0
self.order=QtCore.Qt.SortOrder.DescendingOrder
def rowCount(self, parent=QtCore.QModelIndex()):
return len( self.currentItems )
def columnCount(self, parent=QtCore.QModelIndex()):
return 5
def data(self, index, role):
if not index.isValid(): return
row=index.row()
column=index.column()
item=self.currentItems[row]
if role == QtCore.Qt.DisplayRole:
if column==0: return item.ID
elif column==1: return item.name
elif column==2: return item.category
elif column==4 or column==5: return item.area
if role == QtCore.Qt.UserRole:
return item
def insertRows(self, row, item, column=1, index=QtCore.QModelIndex()):
self.beginInsertRows(QtCore.QModelIndex(), row, row+1)
self.items.append(item)
self.endInsertRows()
def setFilter(self, comboText=None, searchText=None, mainColumn=None, order=None):
if comboText: self.filterCategory=comboText
if searchText: self.searchText=searchText
if mainColumn!=None: self.mainColumn=mainColumn
self.order=order
self.currentItems=[item for item in self.items if item.category==self.filterCategory]
if searchText:
self.currentItems=[item for item in self.currentItems if searchText in '%s%s%s'%(item.ID, item.name, item.category)]
values=[]
if self.mainColumn==0: values=[[item.ID, item, False] for item in self.currentItems]
elif self.mainColumn==1: values=[[item.name, item, False] for item in self.currentItems]
elif self.mainColumn==2: values=[[item.category, item, False] for item in self.currentItems]
elif self.mainColumn==3 or self.mainColumn==4: values=[[item.area, item, False] for item in self.currentItems]
keys=sorted([value[0] for value in values if isinstance(value, list)])
if self.order==QtCore.Qt.AscendingOrder: keys=list(reversed(keys))
filtered=[]
for key in keys:
for each in values:
if each[0]!=key: continue
if each[2]==True: continue
item=each[1]
filtered.append(item)
each[2]=True
if filtered: self.currentItems=filtered
self.layoutChanged.emit()
class ItemDelegate(QtGui.QItemDelegate):
def __init__(self, parent):
QtGui.QItemDelegate.__init__(self, parent)
def flags(self, index):
if (index.column() == 1):
return QtCore.Qt.ItemIsEditable | QtCore.Qt.ItemIsEnabled
else:
return QtCore.Qt.ItemIsEnabled
def createEditor(self, parent, option, index):
tableView=parent.parent()
model=tableView.model()
item=model.data(index, QtCore.Qt.UserRole)
combo=QtGui.QComboBox(parent)
combo.addItems(['South','West','North','East'])
combo.currentIndexChanged.connect(self.comboIndexChanged)
if item.area:
comboIndex=combo.findText(item.area)
if comboIndex>=0:
combo.setCurrentIndex(comboIndex)
else: combo.setCurrentIndex(0)
return combo
def comboIndexChanged(self):
self.commitData.emit(self.sender())
def setModelData(self, combo, model, index):
item=model.data(index, QtCore.Qt.UserRole)
comboText=combo.currentText()
item.area=comboText
class MyWindow(QtGui.QWidget):
def __init__(self, *args):
QtGui.QWidget.__init__(self, *args)
vLayout=QtGui.QVBoxLayout(self)
self.setLayout(vLayout)
self.tableModel = TableModel()
self.searchLine=QtGui.QLineEdit()
vLayout.addWidget(self.searchLine)
self.searchLine.textEdited.connect(self.searchLineEditied)
self.searchLine.returnPressed.connect(self.searchLineEditied)
self.tableView=QtGui.QTableView(self)
self.tableView.setSortingEnabled(True)
self.tableView.horizontalHeader().setResizeMode(QtGui.QHeaderView.Stretch)
self.tableView.setShowGrid(False)
self.tableView.setSelectionBehavior(QtGui.QTableView.SelectRows)
self.tableView.setAlternatingRowColors(True)
self.delegate=ItemDelegate(self.tableView)
self.tableView.setItemDelegate(self.delegate)
self.tableView.clicked.connect(self.viewClicked)
vLayout.addWidget(self.tableView)
for row in range(15):
if row%2: category='Pet'
else: category='Birds'
item=Item(category=category, ID=row, name='%s_%s'%(category,row))
self.tableModel.insertRows(row, item)
self.tableView.setModel(self.tableModel)
self.combo=QtGui.QComboBox()
self.combo.addItems(['Pet','Birds'])
self.combo.activated.connect(self.comboActivated)
vLayout.addWidget(self.combo)
currentComboCategory=self.combo.currentText()
self.tableModel.setFilter(currentComboCategory)
self.horizontalHeader=self.tableView.horizontalHeader()
self.horizontalHeader.sortIndicatorChanged.connect(self.headerTriggered)
self.addComboDelegates()
def headerTriggered(self, mainColumn=None, order=None):
self.tableModel.setFilter(mainColumn=mainColumn, order=order)
self.deleteComboDelegates()
self.addComboDelegates()
def comboActivated(self, comboIndex=None):
self.deleteComboDelegates()
comboText=self.combo.currentText()
self.tableModel.setFilter(comboText=comboText)
self.addComboDelegates()
self.tableModel.layoutChanged.emit()
def searchLineEditied(self, searchText=None):
self.tableModel.setFilter(searchText=searchText)
def viewClicked(self, indexClicked):
item=self.tableModel.data(indexClicked, QtCore.Qt.UserRole)
print 'ID: %s, name: %s, category: %s'%(item.ID,item.name,item.category)
def deleteComboDelegates(self):
for row in range(self.tableModel.rowCount()):
index=self.tableModel.index(row, 3, QtCore.QModelIndex())
self.tableView.closePersistentEditor(index)
def addComboDelegates(self):
for row in range(self.tableModel.rowCount()):
index=self.tableModel.index(row, 3, QtCore.QModelIndex())
self.tableView.openPersistentEditor(index)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())

How to filter and sort Items using Model and QTableView

There are three QTableViews: A, B, C. All three share the same SourceModel.
There are three column names: "Items A", "Items B" and "Items C" stored in self.columnNames list.
Each QTableView was assigned an instance of the same ProxyModel with proxy's objectName set to "proxyA", "proxyB" and "proxyC".
I want the left-side QTableView to list only the items "A" using a single column with its header named "Items A".
The middle tableViewB should only list "Items_B" with the column-header called "Items B".
And the third tableView should list only items "C" with the column name set to "Items C".
The source code is below. I really wanna know how to do it.
from PyQt4.QtCore import *
from PyQt4.QtGui import *
import sys, os
class Model(QAbstractTableModel):
def __init__(self, parent=None, *args):
QAbstractTableModel.__init__(self, parent, *args)
self.items =[
['Item_A_0','Item_A_12','Item_C_330'],
['Item_C_20','Item_B_11','Item_B_12'],
['Item_C_101','Item_A_24','Item_B_77']
]
self.columnNames=['Items A', 'Items B', 'Items C']
def headerData(self, col, orientation, role):
if orientation == Qt.Horizontal and role == Qt.DisplayRole:
return self.columnNames[col]
def flags(self, index):
return Qt.ItemIsEnabled | Qt.ItemIsSelectable | Qt.ItemIsEditable
def rowCount(self, parent):
return len(self.items)
def columnCount(self, parent):
return len(self.columnNames)
def data(self, index, role):
if not index.isValid(): return QVariant()
row=index.row()
column=index.column()
if row>len(self.items): return QVariant()
if column>len(self.items[row]): return QVariant()
columnName=self.headerData(column, Qt.Horizontal, Qt.DisplayRole)
if role == Qt.EditRole or role == Qt.DisplayRole:
return QVariant(self.items[row][column])
return QVariant()
def setData(self, index, value, role=Qt.EditRole):
if index.isValid():
if role == Qt.EditRole:
row = index.row()
column=index.column()
if row>len(self.items) or column>len(self.items[row]):
return False
else:
self.items[row][column]=value
return True
return False
class Proxy(QSortFilterProxyModel):
def __init__(self):
super(Proxy, self).__init__()
def filterAcceptsRow(self, row, parent):
sourceModel=self.sourceModel()
columns=sourceModel.columnCount(QModelIndex())
return True
class MyWindow(QWidget):
def __init__(self, *args):
QWidget.__init__(self, *args)
tablemodel=Model(self)
proxyA=Proxy()
proxyA.setObjectName('proxyA')
proxyA.setSourceModel(tablemodel)
tableviewA=QTableView(self)
tableviewA.setModel(proxyA)
proxyB=Proxy()
proxyB.setObjectName('proxyB')
proxyB.setSourceModel(tablemodel)
tableviewB=QTableView(self)
tableviewB.setModel(proxyB)
proxyC=Proxy()
proxyC.setObjectName('proxyC')
proxyC.setSourceModel(tablemodel)
tableviewC=QTableView(self)
tableviewC.setModel(proxyC)
layout=QHBoxLayout(self)
layout.addWidget(tableviewA)
layout.addWidget(tableviewB)
layout.addWidget(tableviewC)
self.setLayout(layout)
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())

How to prevent QTableView item from getting cleared on double-click

With QTableView set as editable using QAbstractTableModel's flag() method:
def flags(self, index):
return Qt.ItemIsEnabled | Qt.ItemIsSelectable | Qt.ItemIsEditable
double-clicking the QTableView's item puts this item into the editing mode. By default the pre-existing string disappears from the field and an entire item is blank. I wonder if this behavior can be avoided or overridden?
Here is the QTableView field before the user double-clicks it:
And here is how it looks on double-click:
EDITED WORKING CODE (Many thanks to M4rtini):
from PyQt4.QtCore import *
from PyQt4.QtGui import *
import sys, os
class Model(QAbstractTableModel):
def __init__(self, parent=None, *args):
QAbstractTableModel.__init__(self, parent, *args)
self.items =[
['Row0_Column0','Row0_Column1','Row0_Column2'],
['Row1_Column0','Row1_Column1','Row1_Column2'],
['Row2_Column0','Row2_Column1','Row2_Column2']
]
def flags(self, index):
return Qt.ItemIsEnabled | Qt.ItemIsSelectable | Qt.ItemIsEditable
def rowCount(self, parent):
return len(self.items)
def columnCount(self, parent):
return 3
def data(self, index, role):
if not index.isValid(): return QVariant()
row=index.row()
column=index.column()
if row>len(self.items): return QVariant()
if column>len(self.items[row]): return QVariant()
if role == Qt.EditRole or role == Qt.DisplayRole:
return QVariant(self.items[row][column])
return QVariant()
def setData(self, index, value, role=Qt.EditRole):
if index.isValid():
if role == Qt.EditRole:
row = index.row()
column=index.column()
if row>len(self.items) or column>len(self.items[row]):
return False
else:
self.items[row][column]=value
return True
return False
class MyWindow(QWidget):
def __init__(self, *args):
QWidget.__init__(self, *args)
tablemodel=Model(self)
tableview=QTableView(self)
tableview.setModel(tablemodel)
layout=QVBoxLayout(self)
layout.addWidget(tableview)
self.setLayout(layout)
if __name__ == "__main__":
app = QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())

You need to sett the return value for data when called with EditRole:
def data(self, index, role):
if not index.isValid(): return false
row=index.row()
if row>len(self.items): return false
if role == Qt.DisplayRole or role == Qt.EditRole:
return self.items[row]

pyqt - Change row~cell color in TableView

I have a QTableView with three columns
The second column is about numbers, there are only three types: 1, -1 and 0.
I want to have different colors for this three "types" of numbers (1,-1,0), coloring their rows with different colors. How can i do it?
self.tableView = QTableView(self.tabSentimento)
self.tableView.setGeometry(QRect(550,10,510,700))
self.tableView.setObjectName(_fromUtf8("TabelaSentimento"))
self.tableView.setModel(self.model)
self.tableView.horizontalHeader().setStretchLastSection(True)
obs: I used horizontalheader().setStrechLastSection(True) because I opened an existing csv file (using a button) into my tableview.

You have to define the color in the model, not in the view:
def data(self, index, role):
...
if role == Qt.BackgroundRole:
return QBrush(Qt.yellow)
Edit:
Here's a working example, except for the color part completely stolen from http://www.saltycrane.com/blog/2007/06/pyqt-42-qabstracttablemodelqtableview/
from PyQt4.QtCore import *
from PyQt4.QtCore import *
from PyQt4.QtGui import *
import sys
my_array = [['00','01','02'],
['10','11','12'],
['20','21','22']]
def main():
app = QApplication(sys.argv)
w = MyWindow()
w.show()
sys.exit(app.exec_())
class MyWindow(QTableView):
def __init__(self, *args):
QTableView.__init__(self, *args)
tablemodel = MyTableModel(my_array, self)
self.setModel(tablemodel)
class MyTableModel(QAbstractTableModel):
def __init__(self, datain, parent=None, *args):
QAbstractTableModel.__init__(self, parent, *args)
self.arraydata = datain
def rowCount(self, parent):
return len(self.arraydata)
def columnCount(self, parent):
return len(self.arraydata[0])
def data(self, index, role):
if not index.isValid():
return QVariant()
# vvvv this is the magic part
elif role == Qt.BackgroundRole:
if index.row() % 2 == 0:
return QBrush(Qt.yellow)
else:
return QBrush(Qt.red)
# ^^^^ this is the magic part
elif role != Qt.DisplayRole:
return QVariant()
return QVariant(self.arraydata[index.row()][index.column()])
if __name__ == "__main__":
main()