I have an issue with UIPickerView specifically in iOS 7. I have a picker view with 5 columns. For some columns, when the user touches any item, the PickerView doesn't scrolls to that item. The same issue is found in UIDatePickerView too. Any help is appreciated.
This blog post will shed some light on the changes to the pickerViews.
http://blog.ittybittyapps.com/blog/2013/09/20/lifting-the-lid-on-ios-7s-uipicker/
The changes to the picker architecture were significant and if you need to try to fix it, you might have to build your own picker views.
There are a number of projects on github you could use to roll your own, such as AFPickerView, https://github.com/arkichek/AFPickerView (but clearly that's not the iOS7 kind of picker)