Not long ago, we heard about the RansomWare that hit the android platform, it was so severe that many lost their data(information) stored on their Android devices.
This malicious program had the ability to lock you out from your Android phone and even request for a particular amount from you to enable you get back full access on your phone. This payment has to be made via bitcoin since the bitcoin wallet is highly untraceable at the moment, you can read more about it from the link below.
https://www.cybertechguide.com/2019/08/ransomware-alert-android-devices-are-under-attack

Back to the matter on ground, it's very easy to avoid such infection if you understand what a virus is all about. A computer virus is developed by people just the way you have other programs and softwares. There's is an ongoing series explaining everything you need to know about computer virus, types of computer virus and also how to avoid getting infected.
Read more from the source below

https://www.cybertechguide.com/2019/08/what-is-computer-virus