Email Sign Up version 1.3 is now available on the Google Play store. This app allows you to collect email addresses using an Android tablet.
The latest version allows users to upload a file full of email addresses to a MailChimp list directly from the app. Of course, the MailChimp API Key and Unique List Id have to be set up via the settings screen for the feature to work.
Implementing MailChimp Integration
The integration was made possible thanks to the ChimpBot library. I just used the jar file provided on GitHub. I also made use of the Android AsyncTask to move the network traffic off of the user interface thread and update a progress bar.