MobileUI is described as 'is the first Java-based native UI framework for iOS and Android. Get responsive UIs, fast native code, full native API access and the tooling you love' and is an app in the Development category. There are more than 10 alternatives to MobileUI for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Android. The best alternative is Flutter, which is both free and Open Source. Other great apps like MobileUI are Apache Cordova (Free, Open Source), React Native (Free, Open Source), Ionic Framework (Free, Open Source) and Haxe (Free, Open Source).
Haxe is an open source toolkit based on a modern high level strictly typed programming language, a state-of-the-art light-speed cross-compiler, a complete cross-platform standard library, and ways to access to each platform's native capabilities.
SwiftUI is an innovative, exceptionally simple way to build user interfaces across all Apple platforms with the power of Swift. Build user interfaces for any Apple device using just one set of tools and APIs.