Cross-Platform Stats App Development in Flutter ( if you are working in android only then in java for android only)

I'm looking for an experienced mobile app developer to create a statistics application for both Android and iOS using Flutter. If iOS development presents any challenges, I would consider a pure Android app in Java as an alternative.

The app should provide the following features:
- Daily statistics on user interactions, including number of lock/unlock actions, taps, swipes (up, down, left, right), etc.
- Tracking of app usage, displaying which applications were opened and their frequency throughout the day.

The design of the app should be simple and minimalistic, avoiding unnecessary complexity while ensuring a user-friendly interface. The app should incorporate:
- Graphical charts to visually convey statistics
- Text-based stats for clear and straightforward information delivery

Upon completion, I will require sharing of all code and app files before the payment is released. Ideal candidates for this project should have:
- Proven experience in Flutter and/or Java for Android
- Strong understanding of cross-platform mobile development
- Capability to design simple, yet effective user interfaces
- Experience in implementing graphical data representations in apps.