I have two pickers on my screen. Whenever I navigate to the screen in iOS app I find that the pickers are always open and all options are visible.
It works
That's just how the iOS UIPickerView
component works - there's no way to customize it.
If you want a different kind of UI element, you'll need to write your own, or use one of the many open source libraries, such as:
Googling with these, and similar keywords, yields many other libraries as well.
import from native-base
library instead of react-native