I am using the Adobe Reader app on a Dell Venue 8 7840 running Android 5.1. I have been using the app to read text book PDF files. It has worked well until a few days ago. The lower action has stopped working. When I try to open the table of contents to jump to a new chapter, notation menu, change the page view mode (single page, continuous, etc) or the share menu, the bar just goes away like I had tapped outside the menu.
The only way to get it working is to reboot the whole tablet. I have forced closed Reader, reinstalled, tried different PDF files, but the only thing that works is rebooting.
I did just notice that the page tab at the bottom does work, allowing me to jump to a particular page. However this is not useful enough to be a work-around.
I have done some Android development myself and am familiar with things like log-cat and apk's. If I can provide more information please let me know.
I love the app. Being able to take notes directly in a PDF file is amazing. However, for now it is unusable for my purposes. I will have to find a new app to use for the time being.
Thanks for reporting the issue. Do you have some screen filtering app enabled on your device? There is a known issue with the latest version of Adobe Acrobat when screen filtering apps are installed. While we work towards a fix for this issue, could you please try disabling the screen filtering app when trying to access these buttons? We are sorry for the inconvenience and shall try to provide an update soon. For more details, please refer to this discussion: Troubleshooting: Buttons not working in 16.2/16.3 version
Adobe Acrobat Team