is there any api for calling notification when the user is near one point in the map?
Maybe this sample can get you on the right track - RuntimeQtSamples/offline_geofence at master · ldanzinger/RuntimeQtSamples · GitHub
However, actual push notifications are not supported by Qt itself at this point. You can either write your own in Java/Obj C, and expose through Qt, or you could look into a third party option, like v-play if you need actual push notifications - Notification Plugin | V-Play 2.8 | V-Play Engine