node: 10.16.3
npm: 6.9.0
react-native: 0.61.1
react: 16.9.0
native-base: 2.13.8
expo: none (but snack created, see below)
xcode: 11
When dark mode is turned on the date picker will show all months/dates/years as it does in light mode.
Right now I can only see November and December for months, 17th to the 20th for dates and 2020+ for years when dark mode is turned on. The other options appear to still be part of the picker, but the associated text is not visible.
Turn on dark mode for the device
Open the date picker
Snack to reproduce the issue (as long as the device is in dark mode):
https://snack.expo.io/@kosullivan/nativebase-date-picker-dark-mode
How to enable dark mode:
https://www.howtogeek.com/440078/how-to-enable-dark-mode-on-your-iphone-and-ipad/

iOS only
Only happens when device is in dark mode. Normal mode works fine. It seems that the selectable items are not visible, but non-selectable are. In our case the picker is only for past dates which is why only Nov/Dec are shown for 2019, but they are not selectable).
If you want your issue to be looked at quicker, attach a snack reproducible with your issue. Makes it easier for us!
<DatePicker
...
customStyles={{
...
datePicker:{backgroundColor: '#222'}
}}
/>
any progress?
<DatePicker ... customStyles={{ ... datePicker:{backgroundColor: '#222'} }} />
it doesn't work
even set theme after eject
datePickerTextColor: '#ff0000',
datePickerBg: '#00ff00',
dont work:(