Abstract class that should be derived from by any application that wishes to support fields Abstract base class for field factories.

To use fields in editable text,

1) Define a field factory class (derived from MTextFieldFactory) that implements NewFieldL().

2) Create an instance of the field factory and set this to be the editable text object's field factory (see CPlainText::SetFieldFactory(), or you can specify a field factory in the text object 's NewL()).

3) Create a new field (CPlainText::NewTextFieldL()), specifying the field type UID (the built in field type UID values are defined in flddef.h). This calls the factory's NewFieldL() function.

4) Insert the field into the text object (CPlainText::InsertFieldL()).

5) Evaluate the field (CPlainText::UpdateFieldL()) and then re-evaluate when required.