Validating QTable's cell

[soumyadeep_pan]

I want to validate float values in a particular QTable's cell, so I created a custom table item a set it to the particular cell. I am able to get the line edit of the cell using the createEditor(), and able to validate the values. But When ever I have click that particular cell the previous existing values are reset to NULL, I want to keep the old values present in the cell. I have attached the sample code I have used, I also find out the problem in my code, the problem is I am creating new line edit object inside the createEditor() (tableitem.h), which is the problem. But if I do not create a new object how I can achieve my requirement for validating a cell. Please help me ..