Sometimes, we meet with very little issues, which can be solved so easy, but the way to find the solution is always longer and frustrating. This "white UITextField" is also a frustrating Problem. Click in the UITextField and edit the earlier Text, but how, if you can't see that? More click, of course, helps on it, but there is a final solution.
I experienced it when a simple animation was launched when using Text Field.
This is a system bug, not IOS Simulator cause this, or your code. The solution: You need to bring your UITextField View to front.
1. At StoryBoard, you can do it manually
2. Programmatically you can dot it with this:
Objective-C: [self.view bringSubviewToFront:myTextField];