Hello every one
Android developer (java-kotlin) has 3 years in android native field made a lot of projects depends on different techniques :-
-POS and thermal printer
-Barcode Reader application (QRcode-else...)
-Restfull apis (retrofit - volley )
-Bluetooth connection
-google maps and tracking
-Firebase Services (Realtime database - storage - FCM -authentication- firestore database )
-local databases (Sqlite-room-realm)
-ads integration (google -facebook)