Question

there are three edit field on my mainscreen i want to know which edit field is on focous.

thanks alot

Answer 1

Alternatively, you can have your Mainscreen class implement FocusChangeListener.
If you instantiate your Edit controls as Focusable, and implement the listener:

public void focusChanged(Field field, int eventType)
{
    if(field == YourEditField1)
    {
    }
    else if (field == YourEditField2)
    {
    }
}