Android: NLP library for date recognition in string I am currently working on an android app which should make appointments automatically by reading the incoming messages from your mobile phone. I've managed to create a service which monitors the incoming messages, but now I need an Natural Language Processing algorithm in order to find the date for the appointment.

I've tried DialogFlow, but I found out it cannot be used offline and that is not the purpose of the app. It should work offline too!

Does anyone have a suggestion for a library I can use?
Maybe too late, but you could have a look at HeidelTime. It is a Java library that can detect dates, times, durations and time sets in texts for many languages. The downside of HeidelTime is that it seems to be not maintained since 2018. Also, you need the TreeTagger tool in order to use it. But the README of HeidelTime explains the necessary steps quite detailed.

Another alternative or addition to HeidelTime would be defining several regular expressions of common date and time formats and find these in your input text.