I created a toolbar above the picker with two buttons and worked on ios7, when i run in ios8 crash:
Terminating app two to uncaught exception \'UIVi
UIDatePickerView should not be child class of any super view
Problem:
You have to ensure that the view you will assign to inputView or inputAccessoryView don't belong to any parent view. Maybe when you create these views from xib inside a ViewController, by default they are subviews of a superview.
Solution Tips:
Using method removeFromSuperview for view you will assign to inputView or inputAccessoryView