The data is derived from online sources although I've been hosting my own SQLite version of the dataset on my own server. I've found the app to be pretty useful for keeping up to date with what's on for the nights that I do want to sit down and watch something.
Perhaps other people would find it useful too although I'm currently a bit reluctant to release it to the Google Play Store as I've heard some rumblings in the past around the legality (copyright wise) of EPGs. I have no intention to charge for it or derive any advertising revenue from it. I'm keen to hear if anyone has any info on the current situation.