[PyKDE] Validating user input - PyQt

[joanne matthews (RRes-Roth)]

I would like to validate user input in a table. The input needs to be a
double between 0 and 1 with 4 decimal places. I've implemented some code
to do the job and it Works fine if I create the table and set the
delegate from within the main method. However, when The table is defined
within a method in a class, the system crashes with the message
"python.exe has encountered a problem...". I'd really appreciate it if
someone could take a look. Here's my code below:

import sys
from PyQt4 import QtCore, QtGui

class CropTransitions(QtGui.QDialog):
    def __init__(self, parent=None):
        QtGui.QDialog.__init__(self, parent)
        self.matrixTable=self.createTable(3,3)
        
        mainLayout = QtGui.QVBoxLayout()
        
        tableLayout=QtGui.QHBoxLayout()
        tableLayout.addWidget(self.matrixTable)
        mainLayout.addLayout(tableLayout)
        self.setLayout(mainLayout)
        
    
    def createTable(self,col,row=None):
        table = QtGui.QTableWidget(row, col)
        table.setShowGrid(True)
        palette = QtGui.QPalette()
 
palette.setColor(QtGui.QPalette.Active,QtGui.QPalette.ColorRole(16),QtGu
i.QColor(204,0,0))
        table.setAlternatingRowColors(1) 
 
table.setSelectionBehavior(QtGui.QAbstractItemView.SelectionBehavior(1))
        table.setSelectionMode(QtGui.QAbstractItemView.SelectionMode(1))
 
table.horizontalHeader().setResizeMode(QtGui.QHeaderView.Stretch)
        
        delegate = lineEditDelegate()
        table.setItemDelegate(delegate)
        
        return table
    
class lineEditDelegate(QtGui.QItemDelegate):
    def __init__(self, parent = None):
        QtGui.QItemDelegate.__init__(self, parent)
        
    def createEditor(self, parent, option, index):
        editor = QtGui.QLineEdit(parent)
        editor.setInputMask("0.0000")
        editor.setCursorPosition(0)
        
        return editor
    
    def setEditorData(self, lineEdit, index):
        value = index.model().data(index,
QtCore.Qt.DisplayRole).toString()
        print "value=",value
        lineEdit.setText(value)
    
    def setModelData(self, lineEdit, model, index):
        value = lineEdit.text()

        model.setData(index, QtCore.QVariant(value))
    
    def updateEditorGeometry(self, editor, option, index):
        editor.setGeometry(option.rect)
    
   
if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    dialog = CropTransitions()
    dialog.show()
    sys.exit(app.exec_())