NewsGroup Reader is the usenet client for Android. It is powerful and it's free
（Paid version:https://play.google.com/store/apps/details?id=net.piaohong.NewsReader）

Functions and Features
Support multiple usenet servers
Subscribe groups
Support SSL connections
Support Tree View
Support yEnc Decode
Support Filter
Support Mobile Data Limit
Auto fetch latest headlines of all subscribed groups
Fetch latest full messages in group
Smart gesture navigation
Smart Reading optimization
multiple Reading Mode
Support multiple languages
Show All attachmentsFor example:jpeg GIF TXT APK
PostReply and Share
Support multiple Attach
Support Attach from Camera
Support Attach Image editing
Offline reading
Delete old articles and Cache