update() works fine sometime but not everytime..!!

[wysota]

now 'A' should always be drawn no matter what 'B' ,'C' or 'D' is drawn but when i update it redraws A again and again..which is not required

Why is it not required? You said it should be drawn each time.

,i only want the paintEvent to draw 'B','C' or 'D' for me not 'A' again and again ..but since it updates the view so to see 'A' again i have to redraw it every time...i want to some how define it in such a way that if 'A' is drawn one time it remains on screen no matter how many other updates are done..

This is not possible. You have to draw it every time.