Hi @maina.eric,
I’ve found that with Android date pickers, I can usually set the date on the text field directly without having to interact with the spinner. You could use the MobileBuiltInKeywords.setText() function or MobileBuiltInKeywords.sendKeys().
If it’s important to interact with the spinner for your tests, then it gets a little trickier with scrolling. You could try using an open source library I work on to make it a bit easier, specifically, you could check out the section on Using a TextField with a Picker List
To include the library in your project, you can check out the “Installation” section.
Hope this helps,
Chris