在iPhone SDK中显示UIPickerView时隐藏UITabBar

I've got a view when I want to use UIPickerView but my application supports also UITabBar. I want to display UIPickerView in the same spot where keyboard pops up but the problem is that when I do that tab bar buttons are above picker and only half of it is beign displayed. Is is possible to temporary disable tab bar before I draw a picker and restore it when picker will disappear?I've got a view when I want to use UIPickerView