There is a new version of the Ancestry Android App available in the Google Playstore. The latest version apparently does not add any new functionality but does include bug fixes. That app does allow you to build, update, and show off your online family tree.
The updated Ancestry Android App lets you interact with your Ancestry.com family trees stored online or build a new family tree from scratch. You can add or edit family members and even upload photos. While visiting a relative, an ancestral home, or a cemetery, take a picture and add it to your tree instantly.
You can learn more at https://play.google.com/store/apps/details?id=com.ancestry.android.apps.ancestry.