Apple needs to fix this one.
There is an inconsistency in the way that the UIDatePicker is rendered in Storyboards in Xcode vs. their rendering at runtime. This problem set me back longer than it should have this morning, since its effect was tricky to diagnose. The basic consequence of this was that the custom UIButton I had attached to the top of the date picker (inside a UIView) was not receiving taps and for the life of me I couldn’t figure out why…
First, to diagnose the problem, I used this tip to get the UIView recursiveDescription method working in my Swift project, and I was able to get a dump of the view hierarchy. From that, I could tell that the UIView I had created as a container was at a Y value of -54, and was therefore outside the bounds that I had set for the custom view, and was not receiving tap events.
Then I stumbled on this Stack Overflow post by Florian Mielke, which suggested that there is a typo-bug somewhere in Xcode or iOS in the rendering of UIDatePicker in a Storyboard vs. Runtime:
iphone – iOS 7 UIDatePicker height inconsistency? – Stack Overflow
“I can confirm that using UI(Date)Picker in storyboards has a different height (162.0) than in “reality” (216.0). Therefore you have to adjust the space to container view to fit that ‘real’ date picker height or try to solve it using auto-layout.”
Reconciling that with the output from recursiveDescription totally agreed with this, and once I increased the size of my custom view, taps were once again being received by the Done button!