There are identifiers like ANDROID_ID and DEVICE_ID which can be used for that.
We are planning to use funf app to collect some of the data required for my PhD. We created an app and installed it on two phones and began receiving data in dropbox, however, we were not able to distinguish between the two phones. Is it possible to have some sort of user-ID or phone-ID to help distinguish between the different users since this is important for our analysis.
PhD Research Student
Institute for Transport Studies
Room G.19 Geography East
University of Leeds