I 'm trying to color the rows of a QTableView which has a QIdentityProxyModel model as it 's model (which has as source model a QSqlQueryModel).

This is the code (compilable):
Qt Code: 
  1. from PyQt4 import QtGui, QtCore, QtSql
  2. from PyQt4.QtCore import QModelIndex
  3. from PyQt4.QtGui import *
  4. import sys
  5.  
  6. def main():
  7.     app = QtGui.QApplication(sys.argv)
  8.     w = MyWindow()
  9.     w.show()
  10.     sys.exit(app.exec_())
  11.  
  12. class MyWindow(QtGui.QTableView):
  13.     def __init__(self, *args):
  14.         QtGui.QTableView.__init__(self, *args)
  15.  
  16.         # connect to db (if doesn't exist, it's auto-created)
  17.         self.db = QtSql.QSqlDatabase.addDatabase('QSQLITE')
  18.         self.db.setDatabaseName('test.db')
  19.         self.db.open()
  20.  
  21.         #create a table in db and add some data
  22.         query = QtSql.QSqlQuery()
  23.         query.exec_("DROP TABLE IF EXISTS games")
  24.         query.exec_("CREATE TABLE games(id INTEGER PRIMARY KEY, hometeam TEXT, visitorteam TEXT) ")
  25.         query.exec("INSERT INTO games (hometeam, visitorteam) VALUES ('Star', 'Eagles')")
  26.         query.exec("INSERT INTO games (hometeam, visitorteam) VALUES ('Best team', 'Reds');")
  27.         query.exec("INSERT INTO games (hometeam, visitorteam) VALUES ('NonWinners', 'Loosers');")
  28.         query.exec("INSERT INTO games (hometeam, visitorteam) VALUES ('North', 'South');")
  29.         query.exec("INSERT INTO games (hometeam, visitorteam) VALUES ('East', 'west');")
  30.  
  31.         # set the model
  32.         model = QtSql.QSqlQueryModel(self)
  33.         model.setQuery("SELECT * FROM games")
  34.         proxy_model = ExtraRolesProxyModel(self)#QtGui.QStandardItemModel(0, 2)
  35.         proxy_model.setSourceModel(model);
  36.  
  37.         self.setModel(proxy_model)
  38.  
  39.  
  40.         # paint first two rows
  41.         #model.setRowsToBeColored([0,3])
  42.         rowsToBeColored = []
  43.         for i in range(0, 2):
  44.             rowsToBeColored.append(i)
  45.             #model.setRowsToBeColored(rowsToBeColored)
  46.             index = QtCore.QModelIndex(model.index(i, 0))
  47.             model.setData(index, QtCore.Qt.red, QtCore.Qt.BackgroundRole)
  48.  
  49.  
  50.  
  51.  
  52. class ExtraRolesProxyModel(QIdentityProxyModel ):
  53.     def __init__(self, dbcursor=None):
  54.         super(ExtraRolesProxyModel, self).__init__()
  55.         #self.m_extraRoles = []
  56.     def data(self, index, role):
  57.         hashKey = index.row() << 32 | index.column()
  58.         tableIter = self.m_extraRoles.constFind(hashKey)
  59.         if tableIter==self.m_extraRoles.constEnd:
  60.             return QtSql.QSqlQueryModel.data(index,role);
  61.         roleIter = tableIter.value().constFind(role)
  62.         if roleIter==tableIter.value().constEnd():
  63.             return QtSql.QSqlQueryModel.data(index,role);
  64.         return roleIter.value()
  65.  
  66.     def setData(self, index, value, role=None):
  67.         if not index.isValid():
  68.             return False
  69.         hashKey = index.row() << 32 | index.column()
  70.         if value:
  71.             self.m_extraRoles[hashKey][role] = value
  72.             self.dataChanged.emit(index,index)
  73.             return True;
  74.         tableIter = self.m_extraRoles.find(hashKey)
  75.         if tableIter== self.m_extraRoles.end():
  76.             return False
  77.         roleIter = tableIter.value().find(role)
  78.         if roleIter==tableIter.value().end():
  79.             return False
  80.         tableIter.value().erase(roleIter)
  81.         if tableIter.value().isEmpty():
  82.             self.m_extraRoles.erase(tableIter)
  83.         self.dataChanged.emit(index, index)
  84.         return True
  85.  
  86.  
  87. if __name__ == "__main__":
  88.     main()
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I get error:
"tableIter = self.m_extraRoles.constFind(hashKey)
AttributeError: 'ExtraRolesProxyModel' object has no attribute 'm_extraRoles"

The class ExtraRolesProxyModel is a 'translation' from C++, this is the C+++ code of it:
Qt Code: 
  1. #include <QIdentityProxyModel>
  2. class  ExtraRolesProxyModel : public QIdentityProxyModel
  3. {
  4.     Q_OBJECT
  5.     Q_DISABLE_COPY(ExtraRolesProxyModel)
  6. public:
  7.     explicit ExtraRolesProxyModel(QObject* parent=Q_NULLPTR)
  8.         :QIdentityProxyModel(parent)
  9.     {}
  10.     virtual QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const Q_DECL_OVERRIDE{
  11.         const qint64 hashKey = (static_cast<qint64>(index.row()) << 32) | static_cast<qint64>(index.column());
  12.         auto tableIter = m_extraRoles.constFind(hashKey);
  13.         if(tableIter==m_extraRoles.constEnd())
  14.             return QIdentityProxyModel::data(index,role);
  15.         auto roleIter = tableIter.value().constFind(role);
  16.         if(roleIter==tableIter.value().constEnd())
  17.             return QIdentityProxyModel::data(index,role);
  18.         return roleIter.value();
  19.     }
  20.     virtual bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) Q_DECL_OVERRIDE {
  21.         if(!index.isValid())
  22.             return false;
  23.         Q_ASSERT(index.model()==this);
  24.         const qint64 hashKey = (static_cast<qint64>(index.row()) << 32) | static_cast<qint64>(index.column());
  25.         if(value.isValid()){
  26.             m_extraRoles[hashKey][role] = value;
  27.             emit dataChanged(index,index,QVector<int>(1,role));
  28.             return true;
  29.         }
  30.         auto tableIter = m_extraRoles.find(hashKey);
  31.         if(tableIter==m_extraRoles.end())
  32.             return false;
  33.         auto roleIter = tableIter.value().find(role);
  34.         if(roleIter==tableIter.value().end())
  35.             return false;
  36.         tableIter.value().erase(roleIter);
  37.         if(tableIter.value().isEmpty())
  38.             m_extraRoles.erase(tableIter);
  39.         emit dataChanged(index,index,QVector<int>(1,role));
  40.         return true;
  41.     }
  42.  
  43. private:
  44.     QHash<qint64,QHash<qint32,QVariant> > m_extraRoles;
  45. };
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Any ideas are welcome.