I want to build a mobile application for Vietnamese travellers that keeps every part of their trip in one tidy place. The interface and all copy will appear only in Tiếng Việt, so every label, hint and error message must load from a single-language resource file. Core flow • People create a day-by-day lịch trình, adding or re-ordering stops with simple drag-and-drop. • While they type a city or landmark, the app suggests địa điểm gợi ý pulled in real time from a public tourism API (you may propose the source). • Each stop opens straight into Bản đồ dẫn đường using the device’s native Maps or an embedded Google Maps view. The main screen that shows what the traveller has planned is a clean calendar grid; tapping any day expands the details underneath. Although I am open to Flutter, React Native or Kotlin/Swift, the finished product must run smoothly on current Android and iOS versions and be easy for me to localise further if I decide to add more languages later. Deliverables • Source code with clear project structure and comments in English or Vietnamese • Build-ready files (APK + iOS archive/testflight) • One-page setup guide so I can compile future releases myself I will test by planning a three-day trip, checking that suggestions appear promptly, calendar items sync in real time, and map navigation opens at the correct coordinates.