iOS how can display picker view in actionsheet

hi all,
i am new to iphone programming
i want to display three picker view in my view but one picker view cover the half area of the view. so no more space is available for other two picker view and other controls. so i decided to show the picker view in action sheet at appropriate event. but i have no idea that how can i display picker view in action sheet.
can anybody provide me some useful links for this task?

dejo said:

How about just popping up the appropriate pickerView based on some action, like the tap of a button? You could have three buttons, one for each pickerView.

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can you explain little more or provide some code/link. I have no idea that how can i popup the picker view in modal form.