I am making an app that needs to open Google Maps by passing waypoints. But at some point the route may change, how can I send the new route and monitor it to perform functions based on the current position?

I am making an app that needs to open Google Maps by passing waypoints. But at some point the route may change, how can I send the new route and monitor it to perform functions based on the current position?

I am making an app that needs to open Google Maps by passing waypoints. But at some point the route may change, how can I send the new route and monitor it to perform functions based on the current position?

I am making an app that needs to open Google Maps by passing waypoints. But at some point the route may change, how can I send the new route and monitor it to perform functions based on the current position?

I am making an app that needs to open Google Maps by passing waypoints. But at some point the route may change, how can I send the new route and monitor it to perform functions based on the current position?

Video of problem

I have been trying adding circle over google map using following code