Difference between navigationClick(),invocAction() & FieldChangeListener() for any Field in Blackberry

I am confused when i have to use navigationClick开发者_如何学JAVA(),invocAction() or FieldChangeListener(). And which one is best suitable for non-touch and touch Devices.

Plz help me.

As far as I know the change listener gets called every time every the field is changed, for example every single character input would call the listener even if you are still inputing info.

Not much, but I wish I have helped ;)