tabview .. edit to display mode

hello ppl,

I have a problem in my tabview.

i have a screen 100.I have a tabview with 3 tabs on it and each ta contains a ALV. I have to switch this screen from display and change mode and vice-versa.

so i have used in the PBO...

loop at screen

LOOP AT SCREEN.

screen-input = 0. or = 1

MODIFY SCREEN.

ENDLOOP.

endloop

unfortunatly.... my tabview always remains in a change mode.....

the loop dose not recognise the tabviw and the subscreens....

can any one solve my problem