Since I remember my needs back then, I know that hybrid apps were not an option, Also JNI is not used for making cross-platform apps but the best use is to drive hardware peripherals via native UNIX scripts for Android or run c++ code on Android. So if we omit PhoneGap, Appcelerator, Ionic etc we will be facing several cross-platform technologies that have attracted many developer attentions so far.
Xamarin:
The framework was founded by the same people who have created Mono, an Ecma standard-compliant, .NET Framework-compatible set of tools. Xamarin offers developers a single C# codebase that can be used to produce native apps for all major mobile operating systems.
Unlike many other frameworks, Xamarin has already been used by over 1.4 million developers from around the world. Thanks to Xamarin for Visual Studio, developers can take advantage of the power of Microsoft Visual Studio and all its advanced features, including code completion, IntelliSense, and debugging of apps on a simulator or a device. Xamarin Test Cloud makes it possible to instantly test apps on 2,000 real devices in the cloud. This is by far the best way how to deal with the heavy fragmentation of the Android ecosystem and released bug-free apps that work without any major issues.
But being honest I didn't enjoy my first time face-to-face meeting with Xamarin. There were so many bugs and also speed and performance problems were bothering.
React Native
React Native is developed by Facebook and used by Instagram, Airbnb, Walmart, Tesla, Baidu, and many other Fortune 500 companies. It is an open-source version of Facebook’s React JavaScript framework. Because React Native uses the same UI building blocks as regular iOS and Android apps, it’s impossible to distinguish a React Native app from an app built using Objective-C or Java. As soon as you update the source code, you can see the changes instantly manifest in an app preview window. Should you ever feel the urge to manually optimize certain parts of your application, React Native lets you combine native code with components written in Objective-C, Java, or Swift.
The ones I mentioned above are not the only options, but since now they are the most used frameworks between programmers. But beware that Flutter is being publicly announced by Google in Google IO and maybe it may be going to create a hit soon.