How to write a new control

You might need to write a new control for a number of reasons:

• to display application-specific data in an application program

• to add an extra re-usable concrete control to those in the supplied user libraries

To write a new control class you must write a class that is derived from CCoeControl, and implement CCoeControl’s virtual functions so that the control can:

• construct itself

• draw itself on the screen

• accept user input events

Additionally, if the control is a compound control, you should implement virtual functions so that the control can:

• count its components, and return pointers to them

• control the layout of its components

• control keyboard focus for its components

See How to write compound controls for more information for more information.

The CCoeControl-derived class will also typically contain data and functions that are specific to the individual control.