Mobile Registration Screen with Approval Workflow

I'm seeking a skilled developer to create a registration screen for an Android-based mobile application. This screen will incorporate a multi-tiered approval process with various user roles involved: Admin, Manager, and Employee.

Key Features:
- Approval/Reject options for each user
- Notifications sent to the approving authority at each level

Ideal Skills:
- Mobile App Development (Android)
- Experience with creating approval workflows
- Strong understanding of User Role Management
- Proficient in implementing notification systems

Please provide examples of similar projects you've completed.