That depends on what you mean. You can install Ajax Chat onto a web server and use the URL to access the chat. If I'm not mistaken, you can also embed that URL in an Android App. I'm not sure how well that would work. It's better to access it via a browser. It also isn't really great on most Android phones. It works, but... meh. Tablets it is a little better, but AJAX Chat was more designed for the Desktop experience.
With this said, this project is barely supported at this point. If you aren't invested into it and looking to integrate a chat system into an Android app, these are some ideas you may use:
https://medium.com/glucosio-project/how-to-add-a-live-chat-to-your-android-app-for-free-in-10-minutes-dfe2253720cehttps://sendbird.com/