Introduction

Intel’s Multi-OS Engine Technology Preview lets you use Java* capabilities to develop native mobile applications for Apple iOS* and Android* devices providing the native look, feel and performance. This technology provides a stand-alone plug-in that integrates into Android Studio* on Windows* and/or Apple macOS development machines.

An application starts as an Android project in Android Studio. The Multi-OS Engine configures the project to build and run as an iOS app on the iOS simulator that you can invoke from Android Studio or on a real device.

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The key features of Multi-OS Engine are:

  • Java support on iOS devices.

  • Developing iOS apps in Java instead of Apple Objective-C*.

  • Direct access to platform-specific UI components for either of the supported platforms.

  • Native multithreading support.

  • Debugging apps on real devices or the iOS simulator integrated with Android Studio.

  • Running/deploying apps from Apple App Store*.

To get started, follow the instructions in the Getting Started section.

Multi-OS Engine Architecture Overview

Multi-OS Engine Runtime is based on the modern Android ART*, which is the runtime component of Android that runs Java apps.

ART has a list of features that provide optimal performance for apps on iOS devices:

  • Ahead-of-time (AOT) compilation, which can improve app performance.

  • Use of the same Java runtime libraries as Android, which simplify cross-platform app development.

  • Enhanced memory management and garbage collection.

A compiled Multi-OS Engine app contains the following components:

  • Compiled Java sources.

  • Resources.

  • Standard (iOS) library bindings.

  • Third party native libraries and bindings.

  • Nat/J native library for the Java to native binding that enables the implementation of native classes and functions in pure Java and makes them available to the native side.

  • The specialized ART virtual machine (VM) with Multi-OS Engine ART enhancements.

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When an iOS app launches, it starts the ART VM and executes the pre-compiled code on it.

iOS* Development Workflow with the Multi-OS Engine

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  1. Create an Android project in Android Studio. To configure your iOS app, add a new configuration Multi-OS Engine Project. Other steps below explain only the creation of iOS* App with Multi-OS Engine, and assume you are aware of the build process of an Android app in Android Studio.

  2. Design a User Interface (UI) for iOS in Apple Xcode*.

  3. Bind UI to Java* using the NatJ runtime libraries.

  4. Android Studio is equipped with the Intellisense capabilities to bind the action handlers to the UI elements for iOS.

  5. A local build is supported on macOS development machines where iOS Simulators can be invoked. For Windows* development systems, cloud build is supported.

  6. iOS applications can be run on the Simulator integrated into Android Studio by the Multi-OS Engine configuration or directly on the device itself using USB debugging.

  7. Launch your app by publishing and downloading it from the Apple App Store* for iOS* devices or the Google Play Store* for Android devices.

  8. Reiterate the process. Your goal is to reuse as much code as possible between these two apps.