How to Make some part of qLineEdit editable?

[jayesh.srs]

I am using QT 4.8.2 and i am trying to make some part of qLineEdit as editable.
For eg:
I want to make only the last octet of an IP address as editable, and keep all other three octet as readonly or not editable.

Is there any solution achieve this feature in my application.
Or is there any QT widget other than qLineEdit to implement the same in my application
Please help me get one as soon as possible

Thanks

[wysota]

You can use a custom validator that will prevent unwanted changes.