Secure Native Android App Conversion

I need a developer to convert my web app into a secure native Android app. The web version of this app is ready with code just want to convert it. The app should fully integrate with OneSignal for push notifications.

Key Requirements:
- Native Android development
- Secure app architecture
- OneSignal integration for push notifications

Ideal Skills and Experience:
- Strong expertise in native Android development
- Experience in app security protocols
- Familiarity with OneSignal and push notification setups
- Prior experience in converting web apps to mobile apps is a plus

Please provide examples of similar work done and your approach to ensure security.