Flutter...

Flutter, a recent cross-platfrom toolkit from Google, has the potential to be the dominant way of building mobile apps: one codebase gets you both Android and iOS apps (and maybe Fuschia and other platforms later; it's all open source). Flutter features the Dart programming language, several libraries of UI widgets, hot reload that is somehow much faster than Android Studio's even on the same platform, and lots more. For now, see the Flutter Home Page.

Menu and Map in Flutter prototype app