I have expertise in many types of android applications, Mainly a software engineer and have working with a company for 4 years and provided my services as Project Manager, Mobile Developement Head and now offering my services as freelancer:
Barcode/Scanner based app (Hardware)
Paypal based app
Rental Cars app
In-App Purchases app
Barcode/QR code scanner app (Camera)
Email based app
SMS based app
Google Map app
Offline Map GPS tracking app
Offline Map routing app
Syncing of data
Chatting and location sharing, openfire, xmpp, ejabbered, xamp, FCM etc
Employee time tracking
Camera based apps
Information sharing social App
Picture gallery App
Tourist Guide App
PDF based App, Radea PDF, MuPDF,
Dropbox based App
Calendar based App
Task Management App
Alarm based App
MS Word/Excel/PDF Forms To App Conversion.
Create native app to display your website.
Publish application in Google PlayStore.
Push notification implementation
Flavours integration for multiple applications from same source code.
If you are looking for any solution regarding mobile applications do let me know.